Merge branch 'master' into display-title-additions

src/main/java/carpet/script/CarpetEventServer.java

@@ -5,6 +5,7 @@ import carpet.CarpetSettings;
 import carpet.helpers.TickSpeed;
 import carpet.script.exception.InternalExpressionException;
 import carpet.script.value.BlockValue;
+import carpet.script.value.BooleanValue;
 import carpet.script.value.EntityValue;
 import carpet.script.value.FunctionValue;
 import carpet.script.value.ListValue;
@@ -14,12 +15,16 @@ import carpet.script.value.StringValue;
 import carpet.script.value.Value;
 import carpet.script.value.ValueConversions;
 import carpet.settings.ParsedRule;
+import carpet.utils.CarpetProfiler;
 import carpet.utils.Messenger;
 import com.mojang.brigadier.exceptions.CommandSyntaxException;
 import net.minecraft.block.BlockState;
 import net.minecraft.entity.EntityType;
+import net.minecraft.entity.LivingEntity;
+import net.minecraft.entity.TntEntity;
 import net.minecraft.entity.damage.DamageSource;
 import net.minecraft.entity.passive.MerchantEntity;
+import net.minecraft.entity.projectile.ProjectileEntity;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.command.ServerCommandSource;
 import net.minecraft.entity.Entity;
@@ -41,6 +46,7 @@ import net.minecraft.village.Merchant;
 import net.minecraft.village.TradeOffer;
 import net.minecraft.world.World;
 import net.minecraft.world.chunk.Chunk;
+import net.minecraft.world.explosion.Explosion;
 import org.apache.commons.lang3.tuple.Pair;
 
 import java.util.ArrayList;
@@ -51,6 +57,7 @@ import java.util.HashSet;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
@@ -204,6 +211,7 @@ public class CarpetEventServer
         {
             if (callList.size() > 0)
             {
+                CarpetProfiler.ProfilerToken currentSection = CarpetProfiler.start_section(null, "Scarpet events", CarpetProfiler.TYPE.GENERAL);
                 List<Value> argv = argumentSupplier.get(); // empty for onTickDone
                 ServerCommandSource source;
                 try
@@ -225,6 +233,7 @@ public class CarpetEventServer
                     if (!call.execute(source, argv)) fails.add(call);
                 }
                 for (Callback call : fails) callList.remove(call);
+                CarpetProfiler.end_current_section(currentSection);
             }
         }
 
@@ -862,6 +871,59 @@ public class CarpetEventServer
                 );
             }
         };
+        //copy of Explosion.getCausingEntity() #TRACK#
+        private static LivingEntity getExplosionCausingEntity(Entity entity)
+        {
+            if (entity == null)  return null;
+            else if (entity instanceof TntEntity) return ((TntEntity)entity).getCausingEntity();
+            else if (entity instanceof LivingEntity) return (LivingEntity)entity;
+            else if (entity instanceof ProjectileEntity) {
+                Entity owner = ((ProjectileEntity)entity).getOwner();
+                if (owner instanceof LivingEntity) return (LivingEntity)owner;
+            }
+            return null;
+        }
+
+        public static final Event EXPLOSION_OUTCOME = new Event("explosion_outcome", 8, true)
+        {
+            @Override
+            public void onExplosion(ServerWorld world, Entity e,  Supplier<LivingEntity> attacker, double x, double y, double z, float power, boolean createFire, List<BlockPos> affectedBlocks, List<Entity> affectedEntities, Explosion.DestructionType type)
+            {
+                handler.call(
+                        () -> Arrays.asList(
+                                ListValue.fromTriple(x, y, z),
+                                NumericValue.of(power),
+                                EntityValue.of(e),
+                                EntityValue.of(attacker!= null?attacker.get():Event.getExplosionCausingEntity(e)),
+                                StringValue.of(type.name().toLowerCase(Locale.ROOT)),
+                                BooleanValue.of(createFire),
+                                new ListValue(affectedBlocks.stream().filter(b -> !world.isAir(b)). map( // da heck they send air blocks
+                                        b -> new BlockValue(world.getBlockState(b),world,b)
+                                ).collect(Collectors.toList())),
+                                new ListValue(affectedEntities.stream().map(EntityValue::of).collect(Collectors.toList()))
+                        ), () -> CarpetServer.minecraft_server.getCommandSource().withWorld(world)
+                );
+            }
+        };
+
+
+        public static final Event EXPLOSION = new Event("explosion", 6, true)
+        {
+            @Override
+            public void onExplosion(ServerWorld world, Entity e, Supplier<LivingEntity> attacker, double x, double y, double z, float power, boolean createFire, List<BlockPos> affectedBlocks, List<Entity> affectedEntities, Explosion.DestructionType type)
+            {
+                handler.call(
+                        () -> Arrays.asList(
+                                ListValue.fromTriple(x, y, z),
+                                NumericValue.of(power),
+                                EntityValue.of(e),
+                                EntityValue.of(attacker!= null?attacker.get():Event.getExplosionCausingEntity(e)),
+                                StringValue.of(type.name().toLowerCase(Locale.ROOT)),
+                                BooleanValue.of(createFire)
+                        ), () -> CarpetServer.minecraft_server.getCommandSource().withWorld(world)
+                );
+            }
+        };
 
         public static String getEntityLoadEventName(EntityType<? extends Entity> et)
         {
@@ -982,7 +1044,7 @@ public class CarpetEventServer
         public void onSlotSwitch(ServerPlayerEntity player, int from, int to) {}
         public void onTrade(ServerPlayerEntity player, Merchant merchant, TradeOffer tradeOffer) {}
 
-
+        public void onExplosion(ServerWorld world, Entity e,  Supplier<LivingEntity> attacker, double x, double y, double z, float power, boolean createFire, List<BlockPos> affectedBlocks, List<Entity> affectedEntities, Explosion.DestructionType type) { }
         public void onWorldEvent(ServerWorld world, BlockPos pos) { }
         public void onWorldEventFlag(ServerWorld world, BlockPos pos, int flag) { }
         public void onCarpetRuleChanges(ParsedRule<?> rule, ServerCommandSource source) { }

src/main/java/carpet/script/CarpetScriptHost.java

@@ -3,6 +3,7 @@ package carpet.script;
 import carpet.CarpetServer;
 import carpet.CarpetSettings;
 import carpet.script.api.Auxiliary;
+import carpet.script.argument.FileArgument;
 import carpet.script.argument.FunctionArgument;
 import carpet.script.bundled.Module;
 import carpet.script.command.CommandArgument;
@@ -17,9 +18,11 @@ import carpet.script.value.MapValue;
 import carpet.script.value.NumericValue;
 import carpet.script.value.StringValue;
 import carpet.script.value.Value;
+import carpet.utils.CarpetProfiler;
 import carpet.utils.Messenger;
 
 import com.google.gson.JsonElement;
+import com.mojang.brigadier.arguments.StringArgumentType;
 import com.mojang.brigadier.builder.ArgumentBuilder;
 import com.mojang.brigadier.builder.LiteralArgumentBuilder;
 import com.mojang.brigadier.context.CommandContext;
@@ -32,6 +35,7 @@ import net.minecraft.server.command.ServerCommandSource;
 import net.minecraft.server.network.ServerPlayerEntity;
 import net.minecraft.server.world.ServerWorld;
 import net.minecraft.text.LiteralText;
+import net.minecraft.text.Text;
 import net.minecraft.util.math.BlockPos;
 import org.apache.commons.lang3.tuple.Pair;
 
@@ -43,11 +47,13 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 import static java.lang.Math.max;
+import static net.minecraft.server.command.CommandManager.argument;
 import static net.minecraft.server.command.CommandManager.literal;
 
 public class CarpetScriptHost extends ScriptHost
@@ -122,6 +128,7 @@ public class CarpetScriptHost extends ScriptHost
 
     private static int execute(CommandContext<ServerCommandSource> ctx, String hostName, FunctionArgument<Value> funcSpec, List<String> paramNames) throws CommandSyntaxException
     {
+        CarpetProfiler.ProfilerToken currentSection = CarpetProfiler.start_section(null, "Scarpet command", CarpetProfiler.TYPE.GENERAL);
         CarpetScriptHost cHost = CarpetServer.scriptServer.modules.get(hostName).retrieveOwnForExecution(ctx.getSource());
         List<String> argNames = funcSpec.function.getArguments();
         if ((argNames.size()-funcSpec.args.size()) != paramNames.size())
@@ -135,7 +142,9 @@ public class CarpetScriptHost extends ScriptHost
         Value response = cHost.handleCommand(ctx.getSource(), funcSpec.function, args);
         // will skip prints for new
         //if (!response.isNull()) Messenger.m(ctx.getSource(), "gi " + response.getString());
-        return (int) response.readInteger();
+        int intres = (int) response.readInteger();
+        CarpetProfiler.end_current_section(currentSection);
+        return intres;
     }
 
     public LiteralArgumentBuilder<ServerCommandSource> addPathToCommand(
@@ -205,12 +214,15 @@ public class CarpetScriptHost extends ScriptHost
         return s -> {
             try
             {
+                CarpetProfiler.ProfilerToken currentSection = CarpetProfiler.start_section(null, "Scarpet command", CarpetProfiler.TYPE.GENERAL);
                 CarpetScriptHost cHost = null;
                 cHost = CarpetServer.scriptServer.modules.get(hostName).retrieveOwnForExecution(s);
                 Value response = cHost.handleCommand(s, fun, Collections.singletonList(
                         (s.getEntity() instanceof ServerPlayerEntity)?new EntityValue(s.getEntity()):Value.NULL)
                 );
-                return response.getBoolean();
+                boolean res = response.getBoolean();
+                CarpetProfiler.end_current_section(currentSection);
+                return res;
             }
             catch (CommandSyntaxException e)
             {
@@ -311,6 +323,107 @@ public class CarpetScriptHost extends ScriptHost
         }
     }
 
+    public Boolean addAppCommands(Consumer<Text> notifier)
+    {
+        if (appConfig.get(StringValue.of("commands")) != null)
+        {
+            try
+            {
+                LiteralArgumentBuilder<ServerCommandSource> command = readCommands(commandValidator);
+                if (command != null)
+                {
+                    scriptServer.server.getCommandManager().getDispatcher().register(command);
+                    return true;
+                }
+                else {
+                    return false;
+                }
+            }
+            catch (CommandSyntaxException cse)
+            {
+                // failed
+                notifier.accept(Messenger.c("r Failed to build command system for "+getName()+" thus failed to load the app ", cse.getRawMessage()));
+                return null;
+            }
+
+        }
+        return addLegacyCommand(notifier);
+    }
+
+    private Boolean addLegacyCommand(Consumer<Text> notifier)
+    {
+        if (main == null) return false;
+        if (getFunction("__command") == null) return false;
+
+        if (scriptServer.isInvalidCommandRoot(getName()))
+        {
+            notifier.accept(Messenger.c("gi Tried to mask vanilla command."));
+            return null;
+        }
+
+        Function<ServerCommandSource, Boolean> configValidator;
+        try
+        {
+            configValidator = getCommandConfigPermissions();
+        }
+        catch (CommandSyntaxException e)
+        {
+            notifier.accept(Messenger.c("rb "+e.getMessage()));
+            return null;
+        }
+        String hostName = getName();
+        LiteralArgumentBuilder<ServerCommandSource> command = literal(hostName).
+                requires((player) -> scriptServer.modules.containsKey(hostName) && commandValidator.apply(player) && configValidator.apply(player)).
+                executes( (c) ->
+                {
+                    CarpetScriptHost targetHost = scriptServer.modules.get(hostName).retrieveOwnForExecution(c.getSource());
+                    Value response = targetHost.handleCommandLegacy(c.getSource(),"__command", null, "");
+                    if (!response.isNull()) Messenger.m(c.getSource(), "gi "+response.getString());
+                    return (int)response.readInteger();
+                });
+
+        for (String function : globaFunctionNames(main, s ->  !s.startsWith("_")).sorted().collect(Collectors.toList()))
+        {
+            if (appConfig.getOrDefault(StringValue.of("legacy_command_type_support"), Value.FALSE).getBoolean())
+            {
+                try
+                {
+                    FunctionValue functionValue = getFunction(function);
+                    command = addPathToCommand(
+                            command,
+                            CommandToken.parseSpec(CommandToken.specFromSignature(functionValue), this),
+                            FunctionArgument.fromCommandSpec(this, functionValue)
+                    );
+                }
+                catch (CommandSyntaxException e)
+                {
+                    return false;
+                }
+            }
+            else
+            {
+                command = command.
+                        then(literal(function).
+                                requires((player) -> scriptServer.modules.containsKey(hostName) && scriptServer.modules.get(hostName).getFunction(function) != null).
+                                executes((c) -> {
+                                    CarpetScriptHost targetHost = scriptServer.modules.get(hostName).retrieveOwnForExecution(c.getSource());
+                                    Value response = targetHost.handleCommandLegacy(c.getSource(),function, null, "");
+                                    if (!response.isNull()) Messenger.m(c.getSource(), "gi " + response.getString());
+                                    return (int) response.readInteger();
+                                }).
+                                then(argument("args...", StringArgumentType.greedyString()).
+                                        executes( (c) -> {
+                                            CarpetScriptHost targetHost = scriptServer.modules.get(hostName).retrieveOwnForExecution(c.getSource());
+                                            Value response = targetHost.handleCommandLegacy(c.getSource(),function, null, StringArgumentType.getString(c, "args..."));
+                                            if (!response.isNull()) Messenger.m(c.getSource(), "gi "+response.getString());
+                                            return (int)response.readInteger();
+                                        })));
+            }
+        }
+        scriptServer.server.getCommandManager().getDispatcher().register(command);
+        return true;
+    }
+
     public LiteralArgumentBuilder<ServerCommandSource> readCommands(Function<ServerCommandSource, Boolean> useValidator) throws CommandSyntaxException
     {
         Value commands = appConfig.get(StringValue.of("commands"));
@@ -440,7 +553,10 @@ public class CarpetScriptHost extends ScriptHost
     {
         try
         {
-            return callLegacy(source, call, coords, arg);
+            CarpetProfiler.ProfilerToken currentSection = CarpetProfiler.start_section(null, "Scarpet command", CarpetProfiler.TYPE.GENERAL);
+            Value res = callLegacy(source, call, coords, arg);
+            CarpetProfiler.end_current_section(currentSection);
+            return res;
         }
         catch (CarpetExpressionException exc)
         {
@@ -680,31 +796,31 @@ public class CarpetScriptHost extends ScriptHost
 
     private void dumpState()
     {
-        Module.saveData(main, null, globalState, false);
+        Module.saveData(main, globalState);
     }
 
     private Tag loadState()
     {
-        return Module.getData(main, null, false);
+        return Module.getData(main);
     }
 
-    public Tag readFileTag(String file, boolean isShared)
+    public Tag readFileTag(FileArgument fdesc)
     {
-        if (getName() == null && !isShared) return null;
-        if (file != null)
-            return Module.getData(main, file, isShared);
+        if (getName() == null && !fdesc.isShared) return null;
+        if (fdesc.resource != null)
+            return fdesc.getNbtData(main);
         if (parent == null)
             return globalState;
         return ((CarpetScriptHost)parent).globalState;
     }
 
-    public boolean writeTagFile(Tag tag, String file, boolean isShared)
+    public boolean writeTagFile(Tag tag, FileArgument fdesc)
     {
-        if (getName() == null && !isShared) return false; // if belongs to an app, cannot be default host.
+        if (getName() == null && !fdesc.isShared) return false; // if belongs to an app, cannot be default host.
 
-        if (file!= null)
+        if (fdesc.resource != null)
         {
-            return Module.saveData(main, file, tag, isShared);
+            return fdesc.saveNbtData(main, tag);
         }
 
         CarpetScriptHost responsibleHost = (parent != null)?(CarpetScriptHost) parent:this;
@@ -717,34 +833,34 @@ public class CarpetScriptHost extends ScriptHost
         return true;
     }
 
-    public boolean removeResourceFile(String resource, boolean isShared, String type)
+    public boolean removeResourceFile(FileArgument fdesc)
     {
-        if (getName() == null && !isShared) return false; //
-        return Module.dropExistingFile(main, resource, type, isShared);
+        if (getName() == null && !fdesc.isShared) return false; //
+        return fdesc.dropExistingFile(main);
     }
 
-    public boolean appendLogFile(String resource, boolean isShared, String type, List<String> data)
+    public boolean appendLogFile(FileArgument fdesc, List<String> data)
     {
-        if (getName() == null && !isShared) return false; // if belongs to an app, cannot be default host.
-        return Module.appendToTextFile(main, resource, type, isShared, data);
+        if (getName() == null && !fdesc.isShared) return false; // if belongs to an app, cannot be default host.
+        return fdesc.appendToTextFile(main, data);
     }
 
-    public List<String> readTextResource(String resource, String type, boolean isShared)
+    public List<String> readTextResource(FileArgument fdesc)
     {
-        if (getName() == null && !isShared) return null;
-        return Module.listFile(main, resource, type, isShared);
+        if (getName() == null && !fdesc.isShared) return null;
+        return fdesc.listFile(main);
     }
     
-    public JsonElement readJsonFile(String resource, String type, boolean isShared)
+    public JsonElement readJsonFile(FileArgument fdesc)
     {
-        if (getName() == null && !isShared) return null;
-        return Module.readJsonFile(main, resource, type, isShared);
+        if (getName() == null && !fdesc.isShared) return null;
+        return fdesc.readJsonFile(main);
     }
 
-    public Stream<String> listFolder(String resource, String type, boolean isShared)
+    public Stream<String> listFolder(FileArgument fdesc)
     {
-        if (getName() == null && !isShared) return null; //
-        return Module.listFolder(main, resource, type, isShared);
+        if (getName() == null && !fdesc.isShared) return null; //
+        return fdesc.listFolder(main);
     }
 
 

src/main/java/carpet/script/CarpetScriptServer.java

@@ -1,19 +1,15 @@
 package carpet.script;
 
 import carpet.CarpetSettings;
-import carpet.script.argument.FunctionArgument;
 import carpet.script.bundled.BundledModule;
 import carpet.CarpetServer;
 import carpet.script.bundled.FileModule;
 import carpet.script.bundled.Module;
-import carpet.script.command.CommandToken;
 import carpet.script.exception.InvalidCallbackException;
 import carpet.script.value.FunctionValue;
-import carpet.script.value.StringValue;
 import carpet.script.value.Value;
+import carpet.utils.CarpetProfiler;
 import carpet.utils.Messenger;
-import com.mojang.brigadier.arguments.StringArgumentType;
-import com.mojang.brigadier.builder.LiteralArgumentBuilder;
 import com.mojang.brigadier.exceptions.CommandSyntaxException;
 import com.mojang.brigadier.tree.CommandNode;
 
@@ -26,6 +22,7 @@ import net.minecraft.util.WorldSavePath;
 import net.minecraft.util.math.BlockPos;
 
 import java.io.IOException;
+import java.nio.file.FileVisitOption;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
@@ -93,6 +90,7 @@ public class CarpetScriptServer
         registerBuiltInScript(BundledModule.carpetNative("chunk_display", false));
         registerBuiltInScript(BundledModule.carpetNative("ai_tracker", false));
         registerBuiltInScript(BundledModule.carpetNative("draw_beta", false));
+        registerBuiltInScript(BundledModule.carpetNative("shapes", true));
         registerBuiltInScript(BundledModule.carpetNative("distance_beta", false));
     }
 
@@ -136,7 +134,8 @@ public class CarpetScriptServer
     {
         try {
             Path folder = server.getSavePath(WorldSavePath.ROOT).resolve("scripts");
-            Files.createDirectories(folder);
+            if (!Files.exists(folder)) 
+                Files.createDirectories(folder);
             Optional<Path>
             scriptPath = Files.list(folder)
                 .filter(script -> 
@@ -149,7 +148,8 @@ public class CarpetScriptServer
             if (FabricLoader.getInstance().getEnvironmentType() == EnvType.CLIENT)
             {
                 Path globalFolder = FabricLoader.getInstance().getConfigDir().resolve("carpet/scripts");
-                Files.createDirectories(globalFolder);
+                if (!Files.exists(globalFolder)) 
+                    Files.createDirectories(globalFolder);
                 scriptPath = Files.walk(globalFolder)
                         .filter(script -> script.getFileName().toString().equalsIgnoreCase(name + ".sc") ||
                                 (allowLibraries && script.getFileName().toString().equalsIgnoreCase(name + ".scl")))
@@ -194,7 +194,8 @@ public class CarpetScriptServer
         }
         try {
             Path worldScripts = server.getSavePath(WorldSavePath.ROOT).resolve("scripts");
-            Files.createDirectories(worldScripts);
+            if (!Files.exists(worldScripts)) 
+                Files.createDirectories(worldScripts);
             Files.list(worldScripts)
                 .filter(f -> f.toString().endsWith(".sc"))
                 .forEach(f -> moduleNames.add(f.getFileName().toString().replaceFirst("\\.sc$","").toLowerCase(Locale.ROOT)));
@@ -202,8 +203,9 @@ public class CarpetScriptServer
             if (includeBuiltIns && (FabricLoader.getInstance().getEnvironmentType() == EnvType.CLIENT))
             {
                 Path globalScripts = FabricLoader.getInstance().getConfigDir().resolve("carpet/scripts");
-                Files.createDirectories(globalScripts);
-                Files.walk(globalScripts)
+                if (!Files.exists(globalScripts))
+                    Files.createDirectories(globalScripts);
+                Files.walk(globalScripts, FileVisitOption.FOLLOW_LINKS)
                     .filter(f -> f.toString().endsWith(".sc"))
                     .forEach(f -> moduleNames.add(f.getFileName().toString().replaceFirst("\\.sc$","").toLowerCase(Locale.ROOT)));
             }
@@ -223,6 +225,7 @@ public class CarpetScriptServer
     public boolean addScriptHost(ServerCommandSource source, String name, Function<ServerCommandSource, Boolean> commandValidator,
                                  boolean perPlayer, boolean autoload, boolean isRuleApp)
     {
+        CarpetProfiler.ProfilerToken currentSection = CarpetProfiler.start_section(null, "Scarpet load", CarpetProfiler.TYPE.GENERAL);
         if (commandValidator == null) commandValidator = p -> true;
         long start = System.nanoTime();
         name = name.toLowerCase(Locale.ROOT);
@@ -267,35 +270,23 @@ public class CarpetScriptServer
         }
         //addEvents(source, name);
         String action = reload?"reloaded":"loaded";
-        if (newHost.appConfig.get(StringValue.of("commands")) != null)
-        {
-            try
-            {
-                LiteralArgumentBuilder<ServerCommandSource> command = newHost.readCommands(commandValidator);
-                if (command != null)
-                {
-                    if (!isRuleApp) Messenger.m(source, "gi "+name+" app "+action+" with /"+name+" command");
-                    server.getCommandManager().getDispatcher().register(command);
-                    CarpetServer.settingsManager.notifyPlayersCommandsChanged();
-                }
-                else {
-                    if (!isRuleApp) Messenger.m(source, "gi "+name+" app "+action);
-                }
-            }
-            catch (CommandSyntaxException cse)
-            {
-                removeScriptHost(source, name, false, false);
-                Messenger.m(source, "r Failed to build command system for "+name+" thus failed to load the app ", cse.getRawMessage());
-                return false;
-            }
-
-        }
-        else if (!addLegacyCommand(source, name, reload, !isRuleApp, commandValidator)) // this needs to be moved to config reader, only supporting legacy command here
+        Boolean isCommandAdded = newHost.addAppCommands(s -> {
+            if (!isRuleApp) Messenger.m(source, s);
+        });
+        if (isCommandAdded == null) // error should be dispatched
         {
             removeScriptHost(source, name, false, false);
-            Messenger.m(source, "r Failed to build command system for "+name+" thus failed to load the app");
-            return false;
         }
+        else if (isCommandAdded)
+        {
+            CarpetServer.settingsManager.notifyPlayersCommandsChanged();
+            if (!isRuleApp) Messenger.m(source, "gi "+name+" app "+action+" with /"+name+" command");
+        }
+        else
+        {
+            if (!isRuleApp) Messenger.m(source, "gi "+name+" app "+action);
+        }
+
         if (newHost.isPerUser())
         {
             // that will provide player hosts right at the startup
@@ -307,94 +298,15 @@ public class CarpetScriptServer
             FunctionValue onStart = newHost.getFunction("__on_start");
             if (onStart != null) newHost.callNow(onStart, Collections.emptyList());
         }
+        CarpetProfiler.end_current_section(currentSection);
         long end = System.nanoTime();
         CarpetSettings.LOG.info("App "+name+" loaded in "+(end-start)/1000000+" ms");
         return true;
     }
 
-    private boolean addLegacyCommand(ServerCommandSource source, String hostName, boolean isReload, boolean notifySource, Function<ServerCommandSource, Boolean> useValidator)
+    public boolean isInvalidCommandRoot(String appName)
     {
-        CarpetScriptHost host = modules.get(hostName);
-        String loaded = isReload?"reloaded":"loaded";
-        if (host == null)
-        {
-            return true;
-        }
-        if (host.getFunction("__command") == null)
-        {
-            if (notifySource) Messenger.m(source, "gi "+hostName+" app "+loaded+".");
-            return true;
-        }
-        if (holyMoly.contains(hostName))
-        {
-            Messenger.m(source, "gi "+hostName+" app "+loaded+" with no command.");
-            Messenger.m(source, "gi Tried to mask vanilla command.");
-            return true;
-        }
-
-        Function<ServerCommandSource, Boolean> configValidator;
-        try
-        {
-            configValidator = host.getCommandConfigPermissions();
-        }
-        catch (CommandSyntaxException e)
-        {
-            Messenger.m(source, "rb "+e.getMessage());
-            return false;
-        }
-
-        LiteralArgumentBuilder<ServerCommandSource> command = literal(hostName).
-                requires((player) -> modules.containsKey(hostName) && useValidator.apply(player) && configValidator.apply(player)).
-                executes( (c) ->
-                {
-                    CarpetScriptHost targetHost = modules.get(hostName).retrieveOwnForExecution(c.getSource());
-                    Value response = targetHost.handleCommandLegacy(c.getSource(),"__command", null, "");
-                    if (!response.isNull()) Messenger.m(c.getSource(), "gi "+response.getString());
-                    return (int)response.readInteger();
-                });
-
-        for (String function : host.globaFunctionNames(host.main, s ->  !s.startsWith("_")).sorted().collect(Collectors.toList()))
-        {
-            if (host.appConfig.getOrDefault(StringValue.of("legacy_command_type_support"), Value.FALSE).getBoolean())
-            {
-                try
-                {
-                    FunctionValue functionValue = host.getFunction(function);
-                    command = host.addPathToCommand(
-                            command,
-                            CommandToken.parseSpec(CommandToken.specFromSignature(functionValue), host),
-                            FunctionArgument.fromCommandSpec(host, functionValue)
-                    );
-                }
-                catch (CommandSyntaxException e)
-                {
-                    return false;
-                }
-            }
-            else
-            {
-                command = command.
-                        then(literal(function).
-                                requires((player) -> modules.containsKey(hostName) && modules.get(hostName).getFunction(function) != null).
-                                executes((c) -> {
-                                    CarpetScriptHost targetHost = modules.get(hostName).retrieveOwnForExecution(c.getSource());
-                                    Value response = targetHost.handleCommandLegacy(c.getSource(),function, null, "");
-                                    if (!response.isNull()) Messenger.m(c.getSource(), "gi " + response.getString());
-                                    return (int) response.readInteger();
-                                }).
-                                then(argument("args...", StringArgumentType.greedyString()).
-                                        executes( (c) -> {
-                                            CarpetScriptHost targetHost = modules.get(hostName).retrieveOwnForExecution(c.getSource());
-                                            Value response = targetHost.handleCommandLegacy(c.getSource(),function, null, StringArgumentType.getString(c, "args..."));
-                                            if (!response.isNull()) Messenger.m(c.getSource(), "gi "+response.getString());
-                                            return (int)response.readInteger();
-                                        })));
-            }
-        }
-        if (notifySource) Messenger.m(source, "gi "+hostName+" app "+loaded+" with /"+hostName+" command");
-        server.getCommandManager().getDispatcher().register(command);
-        CarpetServer.settingsManager.notifyPlayersCommandsChanged();
-        return true;
+        return holyMoly.contains(appName);
     }
 
 
@@ -498,11 +410,16 @@ public class CarpetScriptServer
 
     public void tick()
     {
+        CarpetProfiler.ProfilerToken token;
+        token = CarpetProfiler.start_section(null, "Scarpet schedule", CarpetProfiler.TYPE.GENERAL);
         events.tick();
+        CarpetProfiler.end_current_section(token);
+        token = CarpetProfiler.start_section(null, "Scarpet app data", CarpetProfiler.TYPE.GENERAL);
         for (CarpetScriptHost host : modules.values())
         {
             host.tick();
         }
+        CarpetProfiler.end_current_section(token);
     }
 
     public void onClose()
@@ -553,4 +470,9 @@ public class CarpetScriptServer
         init();
         apps.forEach((s, data) -> addScriptHost(server.getCommandSource(), s,data.commandValidator, data.perUser,false, data.isRuleApp));
     }
+
+    public void reAddCommands()
+    {
+        modules.values().forEach(host -> host.addAppCommands(s -> {}));
+    }
 }

src/main/java/carpet/script/Expression.java

@@ -19,7 +19,6 @@ import carpet.script.exception.ExpressionException;
 import carpet.script.exception.InternalExpressionException;
 import carpet.script.exception.ResolvedException;
 import carpet.script.exception.ReturnStatement;
-import carpet.script.exception.ThrowStatement;
 import carpet.script.language.Arithmetic;
 import carpet.script.language.ControlFlow;
 import carpet.script.language.DataStructures;
@@ -232,7 +231,7 @@ public class Expression
         if (exc instanceof ExitStatement)
             return exc;
         if (exc instanceof InternalExpressionException)
-            return new ExpressionException(c, e, token, exc.getMessage(), ((InternalExpressionException) exc).stack);
+            return ((InternalExpressionException) exc).promote(c, e, token);
         if (exc instanceof ArithmeticException)
             return new ExpressionException(c, e, token, "Your math is wrong, "+exc.getMessage());
         if (exc instanceof ResolvedException)
@@ -314,6 +313,11 @@ public class Expression
         addUnaryFunction(name, (v) -> new NumericValue(fun.apply(NumericValue.asNumber(v).getDouble())));
     }
 
+    public void addMathematicalUnaryIntFunction(String name, Function<Double, Long> fun)
+    {
+        addUnaryFunction(name, (v) -> new NumericValue(fun.apply(NumericValue.asNumber(v).getDouble())));
+    }
+
     public void addMathematicalBinaryFunction(String name, BiFunction<Double, Double, Double> fun)
     {
         addBinaryFunction(name, (w, v) ->
@@ -624,9 +628,9 @@ public class Expression
         {
             return exprProvider.get().evalValue(c, expectedType);
         }
-        catch (ContinueStatement | BreakStatement | ReturnStatement | ThrowStatement exc)
+        catch (ContinueStatement | BreakStatement | ReturnStatement exc)
         {
-            throw new ExpressionException(c, this, "Control flow functions, like continue, break, throw or return, should only be used in loops, try blocks, and functions respectively.");
+            throw new ExpressionException(c, this, "Control flow functions, like continue, break or return, should only be used in loops, and functions respectively.");
         }
         catch (ExitStatement exit)
         {
@@ -761,7 +765,7 @@ public class Expression
                     {
                         if (token.surface.equals(";"))
                         {
-                            throw new ExpressionException(c, this, token, "Unnecessary semicolon");
+                            throw new ExpressionException(c, this, token, "Empty expression found for ';'");
                         }
                         throw new ExpressionException(c, this, token, "Missing parameter(s) for operator " + token);
                     }

src/main/java/carpet/script/ScriptHost.java

@@ -37,11 +37,15 @@ public abstract class ScriptHost
 
     public Random getRandom(long aLong)
     {
-        if (randomizers.size() > 1024)
+        if (randomizers.size() > 65536)
             randomizers.clear();
         return randomizers.computeIfAbsent(aLong, Random::new);
     }
 
+    public boolean resetRandom(long aLong) {
+        return randomizers.remove(aLong) != null;
+    }
+
     public static class ModuleData
     {
         Module parent;

src/main/java/carpet/script/Tokenizer.java

@@ -406,6 +406,7 @@ public class Tokenizer implements Iterator<Tokenizer.Token>
         public int pos;
         public int linepos;
         public int lineno;
+        public static final Token NONE = new Token();
         public Token morphedInto(TokenType newType, String newSurface)
         {
             Token created = new Token();

src/main/java/carpet/script/api/Auxiliary.java

@@ -3,11 +3,13 @@ package carpet.script.api;
 import carpet.CarpetServer;
 import carpet.CarpetSettings;
 import carpet.fakes.MinecraftServerInterface;
+import carpet.fakes.ServerWorldInterface;
 import carpet.fakes.StatTypeInterface;
 import carpet.fakes.ThreadedAnvilChunkStorageInterface;
 import carpet.helpers.FeatureGenerator;
 import carpet.mixins.PlayerListHeaderS2CPacketMixin;
 import carpet.script.bundled.Module;
+import carpet.script.argument.FileArgument;
 import carpet.script.CarpetContext;
 import carpet.script.CarpetEventServer;
 import carpet.script.CarpetScriptHost;
@@ -20,7 +22,10 @@ import carpet.script.argument.FunctionArgument;
 import carpet.script.argument.Vector3Argument;
 import carpet.script.exception.ExitStatement;
 import carpet.script.exception.InternalExpressionException;
+import carpet.script.exception.ThrowStatement;
+import carpet.script.exception.Throwables;
 import carpet.script.utils.FixedCommandSource;
+import carpet.script.utils.InputValidator;
 import carpet.script.utils.ScarpetJsonDeserializer;
 import carpet.script.utils.ShapeDispatcher;
 import carpet.script.utils.WorldTools;
@@ -36,6 +41,10 @@ import carpet.script.value.StringValue;
 import carpet.script.value.Value;
 import carpet.script.value.ValueConversions;
 import carpet.utils.Messenger;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
+import net.minecraft.SharedConstants;
 import net.minecraft.block.BlockState;
 import net.minecraft.command.DataCommandStorage;
 import net.minecraft.entity.Entity;
@@ -46,6 +55,7 @@ import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.item.ItemStack;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.nbt.NbtHelper;
+import net.minecraft.nbt.NbtOps;
 import net.minecraft.nbt.StringTag;
 import net.minecraft.nbt.Tag;
 import net.minecraft.network.packet.s2c.play.PlaySoundIdS2CPacket;
@@ -53,6 +63,11 @@ import net.minecraft.network.packet.s2c.play.PlayerListHeaderS2CPacket;
 import net.minecraft.network.packet.s2c.play.TitleS2CPacket;
 import net.minecraft.network.packet.s2c.play.TitleS2CPacket.Action;
 import net.minecraft.particle.ParticleEffect;
+import net.minecraft.resource.DataPackSettings;
+import net.minecraft.resource.ReloadableResourceManagerImpl;
+import net.minecraft.resource.ResourcePackManager;
+import net.minecraft.resource.ResourcePackProfile;
+import net.minecraft.resource.ServerResourceManager;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.command.ServerCommandSource;
 import net.minecraft.server.network.ServerPlayerEntity;
@@ -64,21 +79,42 @@ import net.minecraft.text.LiteralText;
 import net.minecraft.text.Text;
 import net.minecraft.util.Identifier;
 import net.minecraft.util.InvalidIdentifierException;
+import net.minecraft.util.crash.CrashException;
+import net.minecraft.util.Util;
+import net.minecraft.util.WorldSavePath;
+import net.minecraft.util.dynamic.RegistryOps;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.ChunkPos;
 import net.minecraft.util.math.EulerAngle;
 import net.minecraft.util.math.Vec3d;
 import net.minecraft.util.registry.DynamicRegistryManager;
 import net.minecraft.util.registry.Registry;
+import net.minecraft.util.registry.RegistryKey;
+import net.minecraft.world.SaveProperties;
 import net.minecraft.world.World;
+import net.minecraft.world.biome.source.BiomeAccess;
+import net.minecraft.world.border.WorldBorderListener;
+import net.minecraft.world.dimension.DimensionOptions;
+import net.minecraft.world.dimension.DimensionType;
+import net.minecraft.world.gen.GeneratorOptions;
+import net.minecraft.world.gen.chunk.ChunkGenerator;
+import net.minecraft.world.level.UnmodifiableLevelProperties;
+import net.minecraft.world.level.storage.LevelStorage;
+import org.apache.commons.io.FileUtils;
 import org.apache.commons.lang3.tuple.Pair;
-import org.apache.commons.lang3.tuple.Triple;
 
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonParseException;
 
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.net.URI;
+import java.nio.file.FileSystem;
+import java.nio.file.FileSystems;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -97,8 +133,9 @@ import static java.lang.Math.min;
 public class Auxiliary {
     public static final String MARKER_STRING = "__scarpet_marker";
     private static final Map<String, SoundCategory> mixerMap = Arrays.stream(SoundCategory.values()).collect(Collectors.toMap(SoundCategory::getName, k -> k));
-    public static final Gson gson = new GsonBuilder().setPrettyPrinting().disableHtmlEscaping().registerTypeAdapter(Value.class, new ScarpetJsonDeserializer()).create();
+    public static final Gson GSON = new GsonBuilder().setPrettyPrinting().disableHtmlEscaping().registerTypeAdapter(Value.class, new ScarpetJsonDeserializer()).create();
 
+    @Deprecated
     public static String recognizeResource(Value value, boolean isFloder)
     {
         String origfile = value.getString();
@@ -111,28 +148,20 @@ public class Auxiliary {
         return file;
     }
 
-    public static Triple<String, String, Boolean> getFileDescriptor(List<LazyValue> lv, Context c, boolean isFloder)
-    {
-        if (lv.size() < 2) throw new InternalExpressionException("File functions require path and type as first two arguments");
-        String resource = recognizeResource(lv.get(0).evalValue(c), isFloder);
-        String origtype = lv.get(1).evalValue(c).getString().toLowerCase(Locale.ROOT);
-        boolean shared = origtype.startsWith("shared_");
-        String type = shared ? origtype.substring(7) : origtype; //len(shared_)
-        if (!Module.supportedTypes.containsKey(type))
-            throw new InternalExpressionException("Unsupported file type: "+origtype);
-        if (type.equals("folder") && !isFloder)
-            throw new InternalExpressionException("Folder types are no supported for this IO function");
-        return Triple.of(resource, type, shared);
-    }
-
     public static void apply(Expression expression)
     {
         expression.addLazyFunction("sound", -1, (c, t, lv) -> {
             CarpetContext cc = (CarpetContext)c;
-            Identifier soundName = new Identifier(lv.get(0).evalValue(c).getString());
+            if (lv.size() == 0)
+            {
+                Value ret = ListValue.wrap(Registry.SOUND_EVENT.getIds().stream().map(ValueConversions::of));
+                return (_c, _t) -> ret;
+            }
+            String rawString = lv.get(0).evalValue(c).getString();
+            Identifier soundName = new Identifier(rawString);
             Vector3Argument locator = Vector3Argument.findIn(cc, lv, 1);
             if (Registry.SOUND_EVENT.get(soundName) == null)
-                throw new InternalExpressionException("No such sound: "+soundName.getPath());
+                throw new ThrowStatement(rawString, Throwables.UNKNOWN_SOUND);
             float volume = 1.0F;
             float pitch = 1.0F;
             SoundCategory mixer = SoundCategory.MASTER;
@@ -165,6 +194,12 @@ public class Auxiliary {
         expression.addLazyFunction("particle", -1, (c, t, lv) ->
         {
             CarpetContext cc = (CarpetContext)c;
+            if (lv.size() == 0)
+            {
+                Value ret = ListValue.wrap(Registry.PARTICLE_TYPE.getIds().stream().map(ValueConversions::of));
+                return (_c, _t) -> ret;
+            }
+
             MinecraftServer ms = cc.s.getMinecraftServer();
             ServerWorld world = cc.s.getWorld();
             Vector3Argument locator = Vector3Argument.findIn(cc, lv, 1);
@@ -847,39 +882,28 @@ public class Auxiliary {
 
         expression.addLazyFunction("list_files", 2, (c, t, lv) ->
         {
-            Triple<String, String, Boolean> fdesc = getFileDescriptor(lv, c, true);
-            Stream<String> files = ((CarpetScriptHost) c.host).listFolder(fdesc.getLeft(), fdesc.getMiddle(), fdesc.getRight());
+            FileArgument fdesc = FileArgument.from(lv, c, true, FileArgument.Reason.READ);
+            Stream<String> files = ((CarpetScriptHost) c.host).listFolder(fdesc);
             if (files == null) return LazyValue.NULL;
             Value ret = ListValue.wrap(files.map(StringValue::of).collect(Collectors.toList()));
             return (cc, tt) -> ret;
         });
 
-
         expression.addLazyFunction("read_file", 2, (c, t, lv) ->
         {
-            Triple<String, String, Boolean> fdesc = getFileDescriptor(lv, c, false);
+            FileArgument fdesc = FileArgument.from(lv, c, false, FileArgument.Reason.READ);
             Value retVal;
-            if (fdesc.getMiddle().equals("nbt"))
+            if (fdesc.type == FileArgument.Type.NBT)
             {
-                Tag state = ((CarpetScriptHost) c.host).readFileTag(fdesc.getLeft(), fdesc.getRight());
+                Tag state = ((CarpetScriptHost) c.host).readFileTag(fdesc);
                 if (state == null) return LazyValue.NULL;
                 retVal = new NBTSerializableValue(state);
             }
-            else if (fdesc.getMiddle().equals("json"))
+            else if (fdesc.type == FileArgument.Type.JSON)
             {
                 JsonElement json;
-                try
-                {
-                    json = ((CarpetScriptHost) c.host).readJsonFile(fdesc.getLeft(), fdesc.getMiddle(), fdesc.getRight());
-                }
-                catch (JsonParseException e)
-                {
-                    Throwable exception = e;
-                    if(e.getCause() != null)
-                        exception = e.getCause();
-                    throw new InternalExpressionException("Failed to read JSON file: "+exception.getMessage());
-                }
-                Value parsedJson = gson.fromJson(json, Value.class);
+                json = ((CarpetScriptHost) c.host).readJsonFile(fdesc);
+                Value parsedJson = GSON.fromJson(json, Value.class);
                 if (parsedJson == null)
                     retVal = Value.NULL;
                 else
@@ -887,7 +911,7 @@ public class Auxiliary {
             }
             else
             {
-                List<String> content = ((CarpetScriptHost) c.host).readTextResource(fdesc.getLeft(), fdesc.getMiddle(), fdesc.getRight());
+                List<String> content = ((CarpetScriptHost) c.host).readTextResource(fdesc);
                 if (content == null) return LazyValue.NULL;
                 retVal = ListValue.wrap(content.stream().map(StringValue::new).collect(Collectors.toList()));
             }
@@ -895,32 +919,29 @@ public class Auxiliary {
         });
 
         expression.addLazyFunction("delete_file", 2, (c, t, lv) -> {
-            Triple<String, String, Boolean> fdesc = getFileDescriptor(lv, c, false);
-            return ((CarpetScriptHost) c.host).removeResourceFile(fdesc.getLeft(), fdesc.getRight(), fdesc.getMiddle())
-                    ? LazyValue.TRUE
-                    : LazyValue.FALSE;
+            FileArgument fdesc = FileArgument.from(lv, c, false, FileArgument.Reason.DELETE);
+            return ((CarpetScriptHost) c.host).removeResourceFile(fdesc) ? LazyValue.TRUE : LazyValue.FALSE;
         });
 
         expression.addLazyFunction("write_file", -1, (c, t, lv) -> {
             if (lv.size() < 3) throw new InternalExpressionException("'write_file' requires three or more arguments");
-            Triple<String, String, Boolean> fdesc = getFileDescriptor(lv, c, false);
-
+            FileArgument fdesc = FileArgument.from(lv, c, false, FileArgument.Reason.CREATE);
 
             boolean success;
-            if (fdesc.getMiddle().equals("nbt"))
+            if (fdesc.type == FileArgument.Type.NBT)
             {
                 Value val = lv.get(2).evalValue(c);
                 NBTSerializableValue tagValue =  (val instanceof NBTSerializableValue)
                         ? (NBTSerializableValue) val
                         : new NBTSerializableValue(val.getString());
                 Tag tag = tagValue.getTag();
-                success = ((CarpetScriptHost) c.host).writeTagFile(tag, fdesc.getLeft(), fdesc.getRight());
+                success = ((CarpetScriptHost) c.host).writeTagFile(tag, fdesc);
             }
-            else if (fdesc.getMiddle().equals("json"))
+            else if (fdesc.type == FileArgument.Type.JSON)
             {
-                List<String> data = Collections.singletonList(gson.toJson(lv.get(2).evalValue(c).toJson()));
-                ((CarpetScriptHost) c.host).removeResourceFile(fdesc.getLeft(), fdesc.getRight(), fdesc.getMiddle());
-                success = ((CarpetScriptHost) c.host).appendLogFile(fdesc.getLeft(), fdesc.getRight(), fdesc.getMiddle(), data);
+                List<String> data = Collections.singletonList(GSON.toJson(lv.get(2).evalValue(c).toJson()));
+                ((CarpetScriptHost) c.host).removeResourceFile(fdesc);
+                success = ((CarpetScriptHost) c.host).appendLogFile(fdesc, data);
             }
             else
             {
@@ -945,27 +966,22 @@ public class Auxiliary {
                         data.add(lv.get(i).evalValue(c).getString());
                     }
                 }
-                success = ((CarpetScriptHost) c.host).appendLogFile(fdesc.getLeft(), fdesc.getRight(), fdesc.getMiddle(), data);
+                success = ((CarpetScriptHost) c.host).appendLogFile(fdesc, data);
             }
             return success?LazyValue.TRUE:LazyValue.FALSE;
         });
 
-        //write_file
-
         expression.addLazyFunction("load_app_data", -1, (c, t, lv) ->
         {
-            String file = null;
-            boolean shared = false;
+            FileArgument fdesc = new FileArgument(null, FileArgument.Type.NBT, null, false, false, FileArgument.Reason.READ);
             if (lv.size()>0)
             {
                 c.host.issueDeprecation("load_app_data(...) with arguments");
-                file = recognizeResource(lv.get(0).evalValue(c), false);
-                if (lv.size() > 1)
-                {
-                    shared = lv.get(1).evalValue(c).getBoolean();
-                }
+                String resource = recognizeResource(lv.get(0).evalValue(c), false);
+                boolean shared = lv.size() > 1 && lv.get(1).evalValue(c).getBoolean();
+                fdesc = new FileArgument(resource, FileArgument.Type.NBT, null, false, shared, FileArgument.Reason.READ);
             }
-            Tag state = ((CarpetScriptHost)((CarpetContext)c).host).readFileTag(file, shared);
+            Tag state = ((CarpetScriptHost) c.host).readFileTag(fdesc);
             if (state == null)
                 return (cc, tt) -> Value.NULL;
             Value retVal = new NBTSerializableValue(state);
@@ -977,22 +993,19 @@ public class Auxiliary {
             if (lv.size() == 0)
                 throw new InternalExpressionException("'store_app_data' needs NBT tag and an optional file");
             Value val = lv.get(0).evalValue(c);
-            String file = null;
-            boolean shared = false;
+            FileArgument fdesc = new FileArgument(null, FileArgument.Type.NBT, null, false, false, FileArgument.Reason.CREATE);
             if (lv.size()>1)
             {
                 c.host.issueDeprecation("store_app_data(...) with more than one argument");
-                file = recognizeResource(lv.get(1).evalValue(c), false);
-                if (lv.size() > 2)
-                {
-                    shared = lv.get(2).evalValue(c).getBoolean();
-                }
+                String resource = recognizeResource(lv.get(1).evalValue(c), false);
+                boolean shared = lv.size() > 2 && lv.get(2).evalValue(c).getBoolean();
+                fdesc = new FileArgument(resource, FileArgument.Type.NBT, null, false, shared, FileArgument.Reason.CREATE);
             }
             NBTSerializableValue tagValue =  (val instanceof NBTSerializableValue)
                     ? (NBTSerializableValue) val
                     : new NBTSerializableValue(val.getString());
             Tag tag = tagValue.getTag();
-            boolean success = ((CarpetScriptHost)((CarpetContext)c).host).writeTagFile(tag, file, shared);
+            boolean success = ((CarpetScriptHost) c.host).writeTagFile(tag, fdesc);
             return success?LazyValue.TRUE:LazyValue.FALSE;
         });
 
@@ -1089,8 +1102,179 @@ public class Auxiliary {
             if (old_nbt == null) return LazyValue.NULL;
             return (_c, _t) -> new NBTSerializableValue(old_nbt);
         });
+
+        // script run create_datapack('foo', {'foo' -> {'bar.json' -> {'c' -> true,'d' -> false,'e' -> {'foo' -> [1,2,3]},'a' -> 'foobar','b' -> 5}}})
+        expression.addLazyFunction("create_datapack", 2, (c, t, lv) -> {
+            CarpetContext cc = (CarpetContext)c;
+            String origName = lv.get(0).evalValue(c).getString();
+            String name = InputValidator.validateSimpleString(origName, true);
+            MinecraftServer server = cc.s.getMinecraftServer();
+            for (String dpName : server.getDataPackManager().getNames())
+            {
+                if (dpName.equalsIgnoreCase("file/"+name+".zip") ||
+                        dpName.equalsIgnoreCase("file/"+name))
+                    return LazyValue.NULL;
+
+            }
+            Value dpdata = lv.get(1).evalValue(c);
+            if (!(dpdata instanceof MapValue))
+                throw new InternalExpressionException("datapack data needs to be a valid map type");
+            ResourcePackManager packManager = server.getDataPackManager();
+            Path dbFloder = server.getSavePath(WorldSavePath.DATAPACKS);
+            Path packFloder = dbFloder.resolve(name+".zip");
+            if (Files.exists(packFloder) || Files.exists(dbFloder.resolve(name))) return LazyValue.NULL;
+            Boolean [] successful = new Boolean[]{true};
+            server.submitAndJoin( () ->
+            {
+                try {
+                    //Files.createDirectory(packFloder);
+                    try (FileSystem zipfs = FileSystems.newFileSystem(URI.create("jar:" + packFloder.toUri().toString()), ImmutableMap.of("create", "true"))) {
+                        Path zipRoot = zipfs.getPath("/");
+                        zipValueToJson(zipRoot.resolve("pack.mcmeta"), MapValue.wrap(
+                                ImmutableMap.of(StringValue.of("pack"), MapValue.wrap(ImmutableMap.of(
+                                        StringValue.of("pack_format"), new NumericValue(SharedConstants.getGameVersion().getPackVersion()),
+                                        StringValue.of("description"), StringValue.of(name),
+                                        StringValue.of("source"), StringValue.of("scarpet")
+                                )))
+                        ));
+                        walkTheDPMap((MapValue) dpdata, zipRoot);
+                    }
+                    packManager.scanPacks();
+                    ResourcePackProfile resourcePackProfile = packManager.getProfile("file/" + name + ".zip");
+                    if (resourcePackProfile == null || packManager.getEnabledProfiles().contains(resourcePackProfile)) {
+                        throw new IOException();
+                    }
+                    List<ResourcePackProfile> list = Lists.newArrayList(packManager.getEnabledProfiles());
+                    resourcePackProfile.getInitialPosition().insert(list, resourcePackProfile, p -> p, false);
+
+
+                    server.reloadResources(list.stream().map(ResourcePackProfile::getName).collect(Collectors.toList())).
+                            exceptionally(exc -> {
+                                successful[0] = false;
+                                return null;
+                            }).join();
+                    if (!successful[0]) {
+                        throw new IOException();
+                    }
+                } catch (IOException e)
+                {
+                    successful[0] = false;
+                    try {
+                        FileUtils.forceDelete(packFloder.toFile());
+                    } catch (IOException ignored) {
+                        throw new InternalExpressionException("Failed to install a datapack and failed to clean up after it");
+                    }
+
+                }
+            });
+            return successful[0]?LazyValue.TRUE:LazyValue.FALSE;
+        });
+
+        expression.addLazyFunction("enable_hidden_dimensions", 0, (c, t, lv) -> {
+            CarpetContext cc = (CarpetContext)c;
+            // from minecraft.server.Main.main
+            MinecraftServer server = cc.s.getMinecraftServer();
+            LevelStorage.Session session = ((MinecraftServerInterface)server).getCMSession();
+            DataPackSettings dataPackSettings = session.getDataPackSettings();
+            ResourcePackManager resourcePackManager = server.getDataPackManager();
+            DataPackSettings dataPackSettings2 = MinecraftServer.loadDataPacks(resourcePackManager, dataPackSettings == null ? DataPackSettings.SAFE_MODE : dataPackSettings, false);
+            ServerResourceManager serverRM = ((MinecraftServerInterface)server).getResourceManager();
+            ReloadableResourceManagerImpl resourceManager = (ReloadableResourceManagerImpl) serverRM.getResourceManager();
+
+            //believe the other one will fillup based on the datapacks only.
+            resourceManager.close();
+            resourcePackManager.createResourcePacks().forEach(resourceManager::addPack);
+
+            //not sure its needed, but doesn't seem to have a negative effect and might be used in some custom shtuff
+            serverRM.loadRegistryTags();
+
+            RegistryOps<Tag> registryOps = RegistryOps.of(NbtOps.INSTANCE, serverRM.getResourceManager(), (DynamicRegistryManager.Impl) server.getRegistryManager());
+            SaveProperties saveProperties = session.readLevelProperties(registryOps, dataPackSettings2);
+            if (saveProperties == null) return LazyValue.NULL;
+            //session.backupLevelDataFile(server.getRegistryManager(), saveProperties); // no need
+
+            // MinecraftServer.createWorlds
+            // save properties should now contain dimension settings
+            GeneratorOptions generatorOptions = saveProperties.getGeneratorOptions();
+            boolean bl = generatorOptions.isDebugWorld();
+            long l = generatorOptions.getSeed();
+            long m = BiomeAccess.hashSeed(l);
+            Map<RegistryKey<World>, ServerWorld> existing_worlds = ((MinecraftServerInterface)server).getCMWorlds();
+            List<Value> addeds = new ArrayList<>();
+            for (Map.Entry<RegistryKey<DimensionOptions>, DimensionOptions> entry : generatorOptions.getDimensions().getEntries()) {
+                RegistryKey<DimensionOptions> registryKey = entry.getKey();
+                if (!existing_worlds.containsKey(registryKey))
+                {
+                    addeds.add(ValueConversions.of(registryKey.getValue()));
+                    RegistryKey<World> registryKey2 = RegistryKey.of(Registry.DIMENSION, registryKey.getValue());
+                    DimensionType dimensionType3 = entry.getValue().getDimensionType();
+                    ChunkGenerator chunkGenerator3 = entry.getValue().getChunkGenerator();
+                    UnmodifiableLevelProperties unmodifiableLevelProperties = new UnmodifiableLevelProperties(saveProperties, ((ServerWorldInterface) server.getOverworld()).getWorldPropertiesCM());
+                    ServerWorld serverWorld2 = new ServerWorld(server, Util.getMainWorkerExecutor(), session, unmodifiableLevelProperties, registryKey2, dimensionType3, WorldTools.NOOP_LISTENER, chunkGenerator3, bl, m, ImmutableList.of(), false);
+                    server.getOverworld().getWorldBorder().addListener(new WorldBorderListener.WorldBorderSyncer(serverWorld2.getWorldBorder()));
+                    existing_worlds.put(registryKey2, serverWorld2);
+                }
+            }
+            Value ret = ListValue.wrap(addeds);
+            return (_c, _t) -> ret;
+        });
     }
 
+    private static void zipValueToJson(Path path, Value output) throws IOException
+    {
+        JsonElement element = output.toJson();
+        if (element == null)
+            throw new InternalExpressionException("Cannot interpret "+output.getPrettyString()+" as a json object");
+        String string = GSON.toJson(element);
+        Files.createDirectories(path.getParent());
+        BufferedWriter bufferedWriter = Files.newBufferedWriter(path);
+        Throwable incident = null;
+        try
+        {
+            bufferedWriter.write(string);
+        }
+        catch (Throwable shitHappened)
+        {
+            incident = shitHappened;
+            throw shitHappened;
+        }
+        finally
+        {
+            if (incident != null) {
+                try {
+                    bufferedWriter.close();
+                } catch (Throwable otherShitHappened) {
+                    incident.addSuppressed(otherShitHappened);
+                }
+            } else {
+                bufferedWriter.close();
+            }
+        }
+    }
+
+    private static void walkTheDPMap(MapValue node, Path path) throws IOException
+    {
+        Map<Value,Value> items = node.getMap();
+        for (Map.Entry<Value, Value> entry : items.entrySet())
+        {
+            Value val = entry.getValue();
+            String strkey = entry.getKey().getString();
+            Path child = path.resolve(strkey);
+            if (strkey.endsWith(".json"))
+            {
+                zipValueToJson(child, val);
+            }
+            else
+            {
+                if (!(val instanceof MapValue)) throw new InternalExpressionException("Value of "+strkey+" should be a map");
+                Files.createDirectory(child);
+                walkTheDPMap((MapValue) val, child);
+            }
+        }
+    }
+
+
+
     private static <T> Stat<T> getStat(StatType<T> type, Identifier id)
     {
         T key = type.getRegistry().get(id);

src/main/java/carpet/script/api/Inventories.java

@@ -6,6 +6,8 @@ import carpet.script.CarpetContext;
 import carpet.script.Expression;
 import carpet.script.LazyValue;
 import carpet.script.exception.InternalExpressionException;
+import carpet.script.exception.ThrowStatement;
+import carpet.script.exception.Throwables;
 import carpet.script.value.ListValue;
 import carpet.script.value.NBTSerializableValue;
 import carpet.script.value.NullValue;
@@ -91,7 +93,7 @@ public class Inventories {
             Item item = NBTSerializableValue.parseItem(lv.get(0).evalValue(c).getString()).getItem();
             if (lv.size() == 1)
             {
-                Value ret = ListValue.wrap(tagManager.getItems().getTagsFor(item).stream().map(ValueConversions::of).collect(Collectors.toList()));
+                Value ret = ListValue.wrap(tagManager.getItems().getTags().entrySet().stream().filter(e -> e.getValue().contains(item)).map(e -> ValueConversions.of(e.getKey())).collect(Collectors.toList()));
                 return (_c, _t) -> ret;
             }
             String tag = lv.get(1).evalValue(c).getString();
@@ -119,14 +121,7 @@ public class Inventories {
                 }
             }
             List<Recipe<?>> recipes;
-            try
-            {
-                recipes = ((RecipeManagerInterface) cc.s.getMinecraftServer().getRecipeManager()).getAllMatching(type, new Identifier(recipeName));
-            }
-            catch (InvalidIdentifierException ignored)
-            {
-                return LazyValue.NULL;
-            }
+            recipes = ((RecipeManagerInterface) cc.s.getMinecraftServer().getRecipeManager()).getAllMatching(type, new Identifier(recipeName));
             if (recipes.isEmpty())
                 return LazyValue.NULL;
             List<Value> recipesOutput = new ArrayList<>();
@@ -197,17 +192,9 @@ public class Inventories {
         {
             String itemStr = lv.get(0).evalValue(c).getString();
             Item item;
-            try
-            {
-                Identifier id = new Identifier(itemStr);
-                item = Registry.ITEM.get(id);
-                if (item == Items.AIR && !id.getPath().equalsIgnoreCase("air"))
-                    throw new InvalidIdentifierException("boo");
-            }
-            catch (InvalidIdentifierException ignored)
-            {
-                throw new InternalExpressionException("Incorrect item: "+itemStr);
-            }
+            Identifier id = new Identifier(itemStr);
+            item = Registry.ITEM.getOrEmpty(id).orElseThrow(() -> new ThrowStatement(itemStr, Throwables.UNKNOWN_ITEM));
+
             if (!item.hasRecipeRemainder()) return LazyValue.NULL;
             Value ret = new StringValue(NBTSerializableValue.nameFromRegistryId(Registry.ITEM.getId(item.getRecipeRemainder())));
             return (_c, _t ) -> ret;

src/main/java/carpet/script/api/Scoreboards.java

@@ -6,6 +6,8 @@ import carpet.script.CarpetContext;
 import carpet.script.Expression;
 import carpet.script.LazyValue;
 import carpet.script.exception.InternalExpressionException;
+import carpet.script.exception.ThrowStatement;
+import carpet.script.exception.Throwables;
 import carpet.script.value.EntityValue;
 import carpet.script.value.ListValue;
 import carpet.script.value.NullValue;
@@ -33,6 +35,8 @@ import net.minecraft.util.Formatting;
 import net.minecraft.util.Identifier;
 import net.minecraft.util.InvalidIdentifierException;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.stream.Collectors;
 
 public class Scoreboards {
@@ -77,16 +81,27 @@ public class Scoreboards {
                 Value ret = ListValue.wrap(scoreboard.getAllPlayerScores(objective).stream().map(s -> new StringValue(s.getPlayerName())).collect(Collectors.toList()));
                 return (_c, _t) -> ret;
             }
+
             String key = getScoreboardKeyFromValue(lv.get(1).evalValue(c));
-            if (!scoreboard.playerHasObjective(key, objective) && lv.size()==2)
+            if(lv.size()==2) {
+                if(scoreboard.playerHasObjective(key, objective)) {
+                    return (_c,_t) -> NumericValue.of(scoreboard.getPlayerScore(key,objective).getScore());
+                }
                 return LazyValue.NULL;
-            ScoreboardPlayerScore scoreboardPlayerScore = scoreboard.getPlayerScore(key, objective);
-            Value retval = new NumericValue(scoreboardPlayerScore.getScore());
-            if (lv.size() > 2)
-            {
-                scoreboardPlayerScore.setScore(NumericValue.asNumber(lv.get(2).evalValue(c)).getInt());
             }
-            return (_c, _t) -> retval;
+
+            Value value = lv.get(2).evalValue(c);
+            if(value.isNull()) {
+                ScoreboardPlayerScore score = scoreboard.getPlayerScore(key, objective);
+                scoreboard.resetPlayerScore(key,objective);
+                return (_c,_t) -> NumericValue.of(score.getScore());
+            }
+            if (value instanceof NumericValue) {
+                ScoreboardPlayerScore score = scoreboard.getPlayerScore(key, objective);
+                score.setScore(NumericValue.asNumber(value).getInt());
+                return (_c,_t) -> NumericValue.of(score.getScore());
+            }
+            throw new InternalExpressionException("'scoreboard' requires a number or null as the third parameter");
         });
 
         expression.addLazyFunction("scoreboard_remove", -1, (c, t, lv)->
@@ -131,12 +146,13 @@ public class Scoreboards {
                 criterion = ScoreboardCriterion.createStatCriterion(critetionName).orElse(null);
                 if (criterion==null)
                 {
-                    throw new InternalExpressionException("Unknown scoreboard criterion: "+critetionName);
+                    throw new ThrowStatement(critetionName, Throwables.UNKNOWN_CRITERION);
                 }
             }
 
             ScoreboardObjective objective = scoreboard.getObjective(objectiveName);
             if (objective != null) {
+                c.host.issueDeprecation("reading or modifying an objective's criterion with scoreboard_add");
                 if(lv.size() == 1) return (_c, _t) -> StringValue.of(objective.getCriterion().getName());
                 if(objective.getCriterion().equals(criterion) || lv.size() == 1) return LazyValue.NULL;
                 ((Scoreboard_scarpetMixin)scoreboard).getObjectivesByCriterion().get(objective.getCriterion()).remove(objective);
@@ -150,6 +166,72 @@ public class Scoreboards {
             return LazyValue.TRUE;
         });
 
+        expression.addLazyFunction("scoreboard_property", -1, (c, t, lv) ->
+        {
+            if(lv.size() < 2) throw new InternalExpressionException("'scoreboard_property' requires at least two parameters");
+            CarpetContext cc = (CarpetContext)c;
+            Scoreboard scoreboard =  cc.s.getMinecraftServer().getScoreboard();
+            ScoreboardObjective objective = scoreboard.getObjective(lv.get(0).evalValue(c).getString());
+            if(objective == null) return LazyValue.NULL;
+
+            boolean modify = lv.size() > 2;
+            Value setValue = null;
+            if(modify) {
+                setValue = lv.get(2).evalValue(c);
+            }
+            String property = lv.get(1).evalValue(c).getString();
+            switch (property) {
+                case "criterion":
+                    if(modify) {
+                        ScoreboardCriterion criterion = ScoreboardCriterion.createStatCriterion(setValue.getString()).orElse(null);
+                        if (criterion==null) throw new InternalExpressionException("Unknown scoreboard criterion: "+ setValue.getString());
+                        if(objective.getCriterion().equals(criterion) || lv.size() == 1) return LazyValue.FALSE;
+                        ((Scoreboard_scarpetMixin)scoreboard).getObjectivesByCriterion().get(objective.getCriterion()).remove(objective);
+                        ((ScoreboardObjective_scarpetMixin) objective).setCriterion(criterion);
+                        (((Scoreboard_scarpetMixin)scoreboard).getObjectivesByCriterion().computeIfAbsent(criterion, (criterion1) -> Lists.newArrayList())).add(objective);
+                        scoreboard.updateObjective(objective);
+                        return LazyValue.TRUE;
+                    }
+                    return (_c, _t) -> StringValue.of(objective.getCriterion().getName());
+                case "display_name":
+                    if(modify) {
+                        Text text = (setValue instanceof FormattedTextValue)?((FormattedTextValue) setValue).getText():new LiteralText(setValue.getString());
+                        objective.setDisplayName(text);
+                        return LazyValue.TRUE;
+                    }
+                    return (_c, _t) -> new FormattedTextValue(objective.getDisplayName());
+                case "display_slot":
+                    if(modify) {
+                        int slotId = Scoreboard.getDisplaySlotId(setValue.getString());
+                        if(slotId == -1) throw new InternalExpressionException("Unknown scoreboard display slot: " + setValue.getString());
+                        if(objective.equals(scoreboard.getObjectiveForSlot(slotId))) {
+                            return LazyValue.FALSE;
+                        }
+                        scoreboard.setObjectiveSlot(slotId,objective);
+                        return LazyValue.TRUE;
+                    }
+
+                    List<Value> slots = new ArrayList<>();
+                    for(int i = 0; i < 19; i++) {
+                        if (scoreboard.getObjectiveForSlot(i) == objective) {
+                            String slotName = Scoreboard.getDisplaySlotName(i);
+                            slots.add(StringValue.of(slotName));
+                        }
+                    }
+                    return (_c, _t) -> ListValue.wrap(slots);
+                case "render_type":
+                    if(modify) {
+                        ScoreboardCriterion.RenderType renderType = ScoreboardCriterion.RenderType.getType(setValue.getString().toLowerCase());
+                        if(objective.getRenderType().equals(renderType)) return LazyValue.FALSE;
+                        objective.setRenderType(renderType);
+                        return LazyValue.TRUE;
+                    }
+                    return (_c, _t) -> StringValue.of(objective.getRenderType().getName());
+                default:
+                    throw new InternalExpressionException("scoreboard property '" + property + "' is not a valid property");
+            }
+        });
+
         expression.addLazyFunction("scoreboard_display", 2, (c, t, lv) ->
         {
             CarpetContext cc = (CarpetContext)c;
@@ -408,7 +490,7 @@ public class Scoreboards {
                     team.setSuffix(suffix);
                     break;
                 default:
-                    throw new InternalExpressionException("team property " + propertyVal.getString() + " is not a valid property");
+                    throw new InternalExpressionException("team property '" + propertyVal.getString() + "' is not a valid property");
             }
             return LazyValue.TRUE;
         });

src/main/java/carpet/script/api/WorldAccess.java

@@ -19,6 +19,8 @@ import carpet.script.LazyValue;
 import carpet.script.argument.BlockArgument;
 import carpet.script.argument.Vector3Argument;
 import carpet.script.exception.InternalExpressionException;
+import carpet.script.exception.ThrowStatement;
+import carpet.script.exception.Throwables;
 import carpet.script.utils.BiomeInfo;
 import carpet.script.utils.WorldTools;
 import carpet.script.value.BlockValue;
@@ -48,6 +50,7 @@ import net.minecraft.enchantment.Enchantments;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.EntityType;
 import net.minecraft.entity.FallingBlockEntity;
+import net.minecraft.entity.LivingEntity;
 import net.minecraft.entity.ai.pathing.NavigationType;
 import net.minecraft.item.BlockItem;
 import net.minecraft.item.Item;
@@ -59,7 +62,7 @@ import net.minecraft.item.SwordItem;
 import net.minecraft.item.TridentItem;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.nbt.Tag;
-import net.minecraft.server.MinecraftServer;
+import net.minecraft.network.packet.s2c.play.ExplosionS2CPacket;
 import net.minecraft.server.network.ServerPlayerEntity;
 import net.minecraft.server.world.ChunkTicket;
 import net.minecraft.server.world.ChunkTicketType;
@@ -78,6 +81,7 @@ import net.minecraft.util.math.BlockBox;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.ChunkPos;
 import net.minecraft.util.math.Direction;
+import net.minecraft.util.math.Vec3d;
 import net.minecraft.util.registry.Registry;
 import net.minecraft.world.Heightmap;
 import net.minecraft.world.LightType;
@@ -87,6 +91,7 @@ import net.minecraft.world.biome.Biome;
 import net.minecraft.world.chunk.Chunk;
 import net.minecraft.world.chunk.ChunkStatus;
 import net.minecraft.world.chunk.WorldChunk;
+import net.minecraft.world.explosion.Explosion;
 import net.minecraft.world.gen.ChunkRandom;
 import net.minecraft.world.gen.chunk.ChunkGenerator;
 import net.minecraft.world.gen.feature.ConfiguredStructureFeature;
@@ -95,6 +100,7 @@ import net.minecraft.world.level.ServerWorldProperties;
 import net.minecraft.world.poi.PointOfInterest;
 import net.minecraft.world.poi.PointOfInterestStorage;
 import net.minecraft.world.poi.PointOfInterestType;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -106,7 +112,6 @@ import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 import java.util.function.BiFunction;
-import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -121,8 +126,7 @@ public class WorldAccess {
         put("unknown", ChunkTicketType.UNKNOWN);  // unknown
     }};
     // dummy entity for dummy requirements in the loot tables (see snowball)
-    private static FallingBlockEntity DUMMY_ENTITY = new FallingBlockEntity(EntityType.FALLING_BLOCK, null);
-
+    private static FallingBlockEntity DUMMY_ENTITY = null;
     private static LazyValue booleanStateTest(
             Context c,
             String name,
@@ -336,8 +340,8 @@ public class WorldAccess {
                 String poiType = lv.get(locator.offset+1).evalValue(c).getString().toLowerCase(Locale.ROOT);
                 if (!"any".equals(poiType))
                 {
-                    PointOfInterestType type =  Registry.POINT_OF_INTEREST_TYPE.get(new Identifier(poiType));
-                    if (type == PointOfInterestType.UNEMPLOYED && !"unemployed".equals(poiType)) return LazyValue.NULL;
+                    PointOfInterestType type =  Registry.POINT_OF_INTEREST_TYPE.getOrEmpty(new Identifier(poiType))
+                            .orElseThrow(() -> new ThrowStatement(poiType, Throwables.UNKNOWN_POI));
                     condition = (tt) -> tt == type;
                 }
                 if (locator.offset + 2 < lv.size())
@@ -391,9 +395,8 @@ public class WorldAccess {
                 return LazyValue.FALSE;
             }
             String poiTypeString = poi.getString().toLowerCase(Locale.ROOT);
-            PointOfInterestType type =  Registry.POINT_OF_INTEREST_TYPE.get(new Identifier(poiTypeString));
-            // solving lack of null with defaulted registries
-            if (type == PointOfInterestType.UNEMPLOYED && !"unemployed".equals(poiTypeString)) throw new InternalExpressionException("Unknown POI type: "+poiTypeString);
+            PointOfInterestType type =  Registry.POINT_OF_INTEREST_TYPE.getOrEmpty(new Identifier(poiTypeString))
+            		.orElseThrow(() -> new ThrowStatement(poiTypeString, Throwables.UNKNOWN_POI));
             int occupancy = 0;
             if (locator.offset + 1 < lv.size())
             {
@@ -872,9 +875,8 @@ public class WorldAccess {
                 {
                     playerBreak = true;
                     String itemString = val.getString();
-                    item = Registry.ITEM.get(new Identifier(itemString));
-                    if (item == Items.AIR && !itemString.equals("air"))
-                        throw new InternalExpressionException("Incorrect item: " + itemString);
+                    item = Registry.ITEM.getOrEmpty(new Identifier(itemString))
+                            .orElseThrow(() -> new ThrowStatement(itemString, Throwables.UNKNOWN_ITEM));
                 }
             }
             CompoundTag tag = null;
@@ -932,6 +934,7 @@ public class WorldAccess {
                 {
                     if (how > 0)
                         tool.addEnchantment(Enchantments.FORTUNE, (int) how);
+                    if (DUMMY_ENTITY == null) DUMMY_ENTITY = new FallingBlockEntity(EntityType.FALLING_BLOCK, null);
                     Block.dropStacks(state, world, where, be, DUMMY_ENTITY, tool);
                 }
             }
@@ -972,6 +975,88 @@ public class WorldAccess {
             return success ? LazyValue.TRUE : LazyValue.FALSE;
         });
 
+        expression.addLazyFunction("create_explosion", -1, (c, t, lv) ->
+        {
+            if (lv.isEmpty())
+                throw new InternalExpressionException("'create_explosion' requires at least a position to explode");
+            CarpetContext cc = (CarpetContext)c;
+            float powah = 4.0f;
+            Explosion.DestructionType mode = Explosion.DestructionType.BREAK;
+            boolean createFire = false;
+            Entity source = null;
+            LivingEntity attacker = null;
+            Vector3Argument location = Vector3Argument.findIn(cc, lv, 0, false, true);
+            Vec3d pos = location.vec;
+            if (lv.size() > location.offset)
+            {
+                powah = NumericValue.asNumber(lv.get(location.offset).evalValue(c), "explosion power").getFloat();
+                if (powah < 0) throw new InternalExpressionException("Explosion power cannot be negative");
+                if (lv.size() > location.offset+1)
+                {
+                    String strval = lv.get(location.offset+1).evalValue(c).getString();
+                    try {
+                        mode = Explosion.DestructionType.valueOf(strval.toUpperCase(Locale.ROOT));
+                    }
+                    catch (IllegalArgumentException ile) { throw new InternalExpressionException("Illegal explosions block behaviour: "+strval); }
+                    if (lv.size() > location.offset+2)
+                    {
+                        createFire = lv.get(location.offset+2).evalValue(c, Context.BOOLEAN).getBoolean();
+                        if (lv.size() > location.offset+3)
+                        {
+                            Value enVal= lv.get(location.offset+3).evalValue(c);
+                            if (enVal.isNull()) {} // is null already
+                            else if (enVal instanceof EntityValue)
+                            {
+                                source = ((EntityValue) enVal).getEntity();
+                            }
+                            else
+                            {
+                                throw new InternalExpressionException("Fourth parameter of the explosion has to be an entity, not "+enVal.getTypeString());
+                            }
+                            if (lv.size() > location.offset+4)
+                            {
+                                enVal = lv.get(location.offset+4).evalValue(c);
+                                if (enVal.isNull()) {} // is null already
+                                else if (enVal instanceof EntityValue)
+                                {
+                                    Entity attackingEntity =  ((EntityValue) enVal).getEntity();
+                                    if (attackingEntity instanceof LivingEntity)
+                                    {
+                                        attacker = (LivingEntity) attackingEntity;
+                                    }
+                                    else throw new InternalExpressionException("Attacking entity needs to be a living thing, "+
+                                            ValueConversions.of(Registry.ENTITY_TYPE.getId(attackingEntity.getType())).getString() +" ain't it.");
+
+                                }
+                                else
+                                {
+                                    throw new InternalExpressionException("Fifth parameter of the explosion has to be a living entity, not "+enVal.getTypeString());
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+            LivingEntity theAttacker = attacker;
+            float thePowah = powah;
+
+            // copy of ServerWorld.createExplosion #TRACK#
+            Explosion explosion = new Explosion(cc.s.getWorld(), source, null, null, pos.x, pos.y, pos.z, powah, createFire, mode){
+                @Override
+                public @Nullable LivingEntity getCausingEntity() {
+                    return theAttacker;
+                }
+            };
+            explosion.collectBlocksAndDamageEntities();
+            explosion.affectWorld(false);
+            if (mode == Explosion.DestructionType.NONE) explosion.clearAffectedBlocks();
+            cc.s.getWorld().getPlayers().forEach(spe -> {
+                if (spe.squaredDistanceTo(pos) < 4096.0D)
+                    spe.networkHandler.sendPacket(new ExplosionS2CPacket(pos.x, pos.y, pos.z, thePowah, explosion.getAffectedBlocks(), explosion.getAffectedPlayers().get(spe)));
+            });
+            return LazyValue.TRUE;
+        });
+
         // TODO rename to use_item
         expression.addLazyFunction("place_item", -1, (c, t, lv) ->
         {
@@ -1127,7 +1212,8 @@ public class WorldAccess {
             BlockArgument blockLocator = BlockArgument.findIn(cc, lv, 0, true);
             if (blockLocator.offset == lv.size())
             {
-                Value ret = ListValue.wrap(tagManager.getBlocks().getTagsFor(blockLocator.block.getBlockState().getBlock()).stream().map(ValueConversions::of).collect(Collectors.toList()));
+                Block target = blockLocator.block.getBlockState().getBlock();
+                Value ret = ListValue.wrap(tagManager.getBlocks().getTags().entrySet().stream().filter(e -> e.getValue().contains(target)).map(e -> ValueConversions.of(e.getKey())).collect(Collectors.toList()));
                 return (_c, _t) -> ret;
             }
             String tag = lv.get(blockLocator.offset).evalValue(c).getString();
@@ -1151,7 +1237,7 @@ public class WorldAccess {
             if (locator.replacement != null)
             {
                 biome = world.getRegistryManager().get(Registry.BIOME_KEY).get(new Identifier(locator.replacement));
-                if (biome == null) return LazyValue.NULL;
+                if (biome == null) throw new ThrowStatement(locator.replacement, Throwables.UNKNOWN_BIOME) ;
             }
             else
             {
@@ -1180,9 +1266,8 @@ public class WorldAccess {
                 throw new InternalExpressionException("'set_biome' needs a biome name as an argument");
             String biomeName = lv.get(locator.offset+0).evalValue(c).getString();
             // from locatebiome command code
-            Biome biome = cc.s.getMinecraftServer().getRegistryManager().get(Registry.BIOME_KEY).get(new Identifier(biomeName));
-            if (biome == null)
-                throw new InternalExpressionException("Unknown biome: "+biomeName);
+            Biome biome = cc.s.getMinecraftServer().getRegistryManager().get(Registry.BIOME_KEY).getOrEmpty(new Identifier(biomeName))
+                .orElseThrow(() -> new ThrowStatement(biomeName, Throwables.UNKNOWN_BIOME));
             boolean doImmediateUpdate = true;
             if (lv.size() > locator.offset+1)
             {
@@ -1251,8 +1336,8 @@ public class WorldAccess {
                 if (!(requested instanceof NullValue))
                 {
                     String reqString = requested.getString();
-                    structure = Registry.STRUCTURE_FEATURE.get(new Identifier(reqString));
-                    if (structure == null) throw new InternalExpressionException("Unknown structure: " + reqString);
+                    structure = Registry.STRUCTURE_FEATURE.getOrEmpty(new Identifier(reqString))
+                            .orElseThrow(() -> new ThrowStatement(reqString, Throwables.UNKNOWN_STRUCTURE));
                 }
                 if (lv.size() > locator.offset+1)
                 {
@@ -1332,7 +1417,7 @@ public class WorldAccess {
                 throw new InternalExpressionException("'set_structure requires at least position and a structure name");
             String structureName = lv.get(locator.offset).evalValue(c).getString().toLowerCase(Locale.ROOT);
             ConfiguredStructureFeature<?, ?> configuredStructure = FeatureGenerator.resolveConfiguredStructure(structureName, world, pos);
-            if (configuredStructure == null) throw new InternalExpressionException("Unknown structure: "+structureName);
+            if (configuredStructure == null) throw new ThrowStatement(structureName, Throwables.UNKNOWN_STRUCTURE);
             // good 'ol pointer
             Value[] result = new Value[]{Value.NULL};
             // technically a world modification. Even if we could let it slide, we will still park it
@@ -1382,6 +1467,7 @@ public class WorldAccess {
         {
             if (lv.size() == 0) throw new InternalExpressionException("'custom_dimension' requires at least one argument");
             CarpetContext cc = (CarpetContext)c;
+            cc.host.issueDeprecation("custom_dimension()");
             String worldKey = lv.get(0).evalValue(c).getString();
 
             Long seed = null;

src/main/java/carpet/script/argument/FileArgument.java

@@ -0,0 +1,502 @@
+package carpet.script.argument;
+
+import carpet.CarpetServer;
+import carpet.script.Context;
+import carpet.script.LazyValue;
+import carpet.script.bundled.Module;
+import carpet.script.exception.InternalExpressionException;
+import carpet.script.exception.ThrowStatement;
+import carpet.script.exception.Throwables;
+import carpet.script.value.MapValue;
+import carpet.script.value.StringValue;
+import carpet.script.value.Value;
+import com.google.common.collect.ImmutableMap;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonParser;
+import com.google.gson.stream.JsonReader;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.NbtIo;
+import net.minecraft.nbt.PositionTracker;
+import net.minecraft.nbt.Tag;
+import net.minecraft.nbt.TagReaders;
+import net.minecraft.util.WorldSavePath;
+import net.minecraft.util.crash.CrashException;
+import org.apache.commons.io.FilenameUtils;
+import org.apache.commons.lang3.tuple.Pair;
+
+import java.io.BufferedInputStream;
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.net.URI;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.FileSystem;
+import java.nio.file.FileSystemNotFoundException;
+import java.nio.file.FileSystems;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class FileArgument
+{
+    public String resource;
+    public Type type;
+    public String zipContainer;
+    public boolean isFolder;
+    public boolean isShared;
+    public Reason reason;
+    private FileSystem zfs;
+    private Path zipPath;
+
+    public final static Object writeIOSync = new Object();
+
+    public void close() {
+        if (zfs != null && zfs.isOpen()) {
+            try {
+                zfs.close();
+            } catch (IOException e) {
+                throw new InternalExpressionException("Unable to close zip container: "+zipContainer);
+            }
+            zfs = null;
+        }
+    }
+
+    public enum Type
+    {
+        RAW("raw", ".txt"),
+        TEXT("text", ".txt"),
+        NBT("nbt", ".nbt"),
+        JSON("json", ".json"),
+        FOLDER("folder", "");
+
+        private final String id;
+        private final String extension;
+
+        public static Map<String, Type> of = Arrays.stream(values()).collect(Collectors.toMap(t -> t.id, t -> t));
+
+        Type(String id, String extension)
+        {
+             this.id = id;
+             this.extension = extension;
+        }
+    }
+
+    public enum Reason
+    {
+        READ, CREATE, DELETE
+    }
+
+    public FileArgument(String resource, Type type, String zipContainer, boolean isFolder, boolean isShared, Reason reason)
+    {
+        this.resource = resource;
+        this.type = type;
+        this.zipContainer = zipContainer;
+        this.isFolder = isFolder;
+        this.isShared = isShared;
+        this.reason = reason;
+        this.zfs = null;
+        this.zipPath = null;
+    }
+
+    @Override
+    public String toString() {
+        return "path: "+resource+" zip: "+zipContainer+" type: "+type.id+" folder: "+isFolder+" shared: "+isShared+" reason: "+reason.toString();
+    }
+
+    public static FileArgument from(List<LazyValue> lv, Context c, boolean isFolder, Reason reason)
+    {
+        if (lv.size() < 2) throw new InternalExpressionException("File functions require path and type as first two arguments");
+        Pair<String, String> resource = recognizeResource(lv.get(0).evalValue(c), isFolder);
+        String origtype = lv.get(1).evalValue(c).getString().toLowerCase(Locale.ROOT);
+        boolean shared = origtype.startsWith("shared_");
+        String typeString = shared ? origtype.substring(7) : origtype; //len(shared_)
+        Type type = Type.of.get(typeString);
+        if (type==null)
+            throw new InternalExpressionException("Unsupported file type: "+origtype);
+        if (type==Type.FOLDER && !isFolder)
+            throw new InternalExpressionException("Folder types are no supported for this IO function");
+        return  new FileArgument(resource.getLeft(), type,resource.getRight(), isFolder, shared, reason);
+
+    }
+
+    public static Pair<String,String> recognizeResource(Value value, boolean isFolder)
+    {
+        String origfile = value.getString();
+        String[] pathElements = origfile.toLowerCase(Locale.ROOT).split("[/\\\\]+");
+        List<String> path = new ArrayList<>();
+        String zipPath = null;
+        for (String token : pathElements)
+        {
+            boolean isZip = token.endsWith(".zip");
+            if (zipPath != null && isZip) throw new InternalExpressionException(token+" indicates zip access in an already zipped location "+zipPath);
+            if (isZip) token = token.substring(0, token.length()-4);
+            token = token.replaceAll("[^A-Za-z0-9\\-+_]", "");
+            if (token.isEmpty()) continue;
+            if (isZip) token = token + ".zip";
+            path.add(token);
+            if (isZip)
+            {
+                zipPath = String.join("/", path);
+                path.clear();
+            }
+        }
+        if (path.isEmpty() && !isFolder)
+            throw new InternalExpressionException(
+                    "Cannot use "+origfile+" as resource name: indicated path is empty"+((zipPath==null)?"":" in zip container "+zipPath)
+            );
+        return Pair.of(String.join("/", path), zipPath);
+    }
+
+    private Path resolve(String suffix)
+    {
+        if (CarpetServer.minecraft_server == null)
+            throw new InternalExpressionException("Accessing world files without server running");
+        return CarpetServer.minecraft_server.getSavePath(WorldSavePath.ROOT).resolve("scripts/"+suffix);
+    }
+
+    private Path toPath(Module module)
+    {
+        if (!isShared && (module == null || module.getName() == null)) return null;
+        if (zipContainer == null)
+            return resolve(getDescriptor(module, resource)+(isFolder?"":type.extension));
+        else
+        {
+            if (zfs == null)
+            {
+                Map<String, String> env = new HashMap<>();
+                if (reason == Reason.CREATE) env.put("create", "true");
+                zipPath = resolve(getDescriptor(module, zipContainer));
+                try {
+                    zfs = FileSystems.newFileSystem(URI.create("jar:"+ zipPath.toUri().toString()), env);
+                }
+                catch (FileSystemNotFoundException fsnfe)
+                {
+                    return null;
+                }
+                catch (IOException e)
+                {
+                    throw new ThrowStatement("Unable to open zip file: "+zipContainer, Throwables.IO_EXCEPTION);
+                }
+            }
+            return zfs.getPath(resource+(isFolder?"/":type.extension));
+        }
+    }
+
+    private Path moduleRootPath(Module module)
+    {
+        if (!isShared && (module == null || module.getName() == null)) return null;
+        return resolve(isShared?"shared":module.getName()+".data");
+    }
+
+    public String getDisplayPath()
+    {
+        return (isShared?"shared/":"")+(zipContainer!=null?zipContainer+"/":"")+resource+type.extension;
+    }
+
+    private String getDescriptor(Module module, String res)
+    {
+        if (isShared)
+        {
+            return res.isEmpty()?"shared":"shared/"+res;
+        }
+        if (module != null && module.getName() != null) // appdata
+        {
+            return module.getName()+".data"+(res==null || res.isEmpty()?"":"/"+res);
+        }
+        throw new InternalExpressionException("Invalid file descriptor: "+res);
+    }
+
+    public Stream<Path> listFiles(Module module)
+    {
+        Path dir = toPath(module);
+        if (dir == null || !Files.exists(dir)) return null;
+        String ext = type.extension;
+        try
+        {
+            return Files.list(dir).filter(path -> (type==Type.FOLDER)?path.toString().endsWith("/"):path.toString().endsWith(ext));
+        }
+        catch (IOException ignored)
+        {
+            return null;
+        }
+    }
+
+    public Stream<String> listFolder(Module module)
+    {
+        Stream<String> strings;
+        try { synchronized (writeIOSync)
+        {
+            Stream<Path> result;
+            result = listFiles(module);
+            if (result == null) return null;
+            Path rootPath = moduleRootPath(module);
+            if (rootPath == null) return null;
+            String zipComponent = (zipContainer != null) ? rootPath.relativize(zipPath).toString() : null;
+            strings = result.map(p -> {
+                if (zipContainer == null)
+                    return rootPath.relativize(p).toString().replaceAll("[\\\\/]+", "/");
+                return (zipComponent + '/'+ p.toString()).replaceAll("[\\\\/]+", "/");
+            });
+        } }
+        finally
+        {
+            close();
+        }
+        if (type == Type.FOLDER)
+            return strings.map(s -> s.endsWith("/")?s.substring(0, s.length()-1):s);
+        return strings.map(FilenameUtils::removeExtension);
+    }
+
+    private void createPaths(Path file)
+    {
+        try {
+            if ((zipContainer == null || file.getParent() != null) &&
+                    !Files.exists(file.getParent()) &&
+                    Files.createDirectories(file.getParent()) == null
+            ) throw new IOException();
+        } catch (IOException e) {
+            throw new ThrowStatement("Unable to create paths for "+file.toString(), Throwables.IO_EXCEPTION);
+        }
+
+    }
+
+    public boolean appendToTextFile(Module module, List<String> message)
+    {
+        try { synchronized (writeIOSync)
+        {
+            Path dataFile = toPath(module);//, resourceName, supportedTypes.get(type), isShared);
+            if (dataFile == null) return false;
+            createPaths(dataFile);
+            OutputStream out = Files.newOutputStream(dataFile, StandardOpenOption.APPEND, StandardOpenOption.CREATE);
+            try (BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(out, StandardCharsets.UTF_8)))
+            {
+                for (String line: message)
+                {
+                    writer.append(line);
+                    if (type == Type.TEXT) writer.newLine();
+                }
+            }
+        } }
+        catch (IOException e)
+        {
+            throw new ThrowStatement("Error when writing to the file: "+e, Throwables.IO_EXCEPTION);
+        }
+        finally
+        {
+            close();
+        }
+        return true;
+    }
+
+    public Tag getNbtData(Module module) // aka getData
+    {
+        try { synchronized (writeIOSync) {
+            Path dataFile = toPath(module);
+            if (dataFile == null || !Files.exists(dataFile)) return null;
+            return readTag(dataFile);
+        } }
+        finally {
+            close();
+        }
+    }
+
+    //copied private method from net.minecraft.nbt.NbtIo.read()
+    // to read non-compound tags - these won't be compressed
+    public static Tag readTag(Path path)
+    {
+        try
+        {
+            return NbtIo.readCompressed(Files.newInputStream(path));
+        }
+        catch (IOException e)
+        {
+            // Copy of NbtIo.read(File) because that's now client-side only
+            if (!Files.exists(path))
+            {
+                return null;
+            }
+            try (DataInputStream in = new DataInputStream(new BufferedInputStream(Files.newInputStream(path))))
+            {
+                return NbtIo.read(in);
+            }
+            catch (IOException ioException)
+            {
+                // not compressed compound tag neither uncompressed compound tag - trying any type of a tag
+                try (DataInputStream dataInput_1 = new DataInputStream(new BufferedInputStream(Files.newInputStream(path))))
+                {
+                    byte byte_1 = dataInput_1.readByte();
+                    if (byte_1 == 0)
+                    {
+                        return null;
+                    }
+                    else
+                    {
+                        dataInput_1.readUTF();
+                        return TagReaders.of(byte_1).read(dataInput_1, 0, PositionTracker.DEFAULT);
+                    }
+                }
+                catch (IOException ignored)
+                {
+                    throw new ThrowStatement("Not a valid NBT tag in "+path.toString(), Throwables.NBT_ERROR);
+                }
+            }
+        }
+        catch (CrashException e)
+        {
+            throw new ThrowStatement("Error when reading NBT file "+path.toString(), Throwables.NBT_ERROR);
+        }
+    }
+
+    public boolean saveNbtData(Module module, Tag tag) // aka saveData
+    {
+        try { synchronized (writeIOSync) {
+            Path dataFile = toPath(module);
+            if (dataFile == null) return false;
+            createPaths(dataFile);
+            return writeTagDisk(tag, dataFile, zipContainer != null);
+        } }
+        finally
+        {
+            close();
+        }
+    }
+
+    //copied private method from net.minecraft.nbt.NbtIo.write() and client method safe_write
+    public static boolean writeTagDisk(Tag tag_1, Path path, boolean zipped)
+    {
+        Path original = path;
+        try
+        {
+            if (!zipped)
+            {
+                path = new File(path.toFile().getAbsolutePath() + "_tmp").toPath();
+                Files.deleteIfExists(path);
+            }
+
+            if (tag_1 instanceof CompoundTag)
+            {
+                NbtIo.writeCompressed((CompoundTag) tag_1, Files.newOutputStream(path));
+            }
+            else
+            {
+                try (DataOutputStream dataOutputStream_1 = new DataOutputStream(Files.newOutputStream(path)))
+                {
+                    dataOutputStream_1.writeByte(tag_1.getType());
+                    if (tag_1.getType() != 0)
+                    {
+                        dataOutputStream_1.writeUTF("");
+                        tag_1.write(dataOutputStream_1);
+                    }
+                }
+            }
+            if (!zipped)
+            {
+                Files.deleteIfExists(original);
+                Files.move(path, original);
+            }
+            return true;
+        }
+        catch (IOException e)
+        {
+            throw new ThrowStatement("Unable to write tag to "+original.toString(), Throwables.IO_EXCEPTION);
+        }
+    }
+
+    public boolean dropExistingFile(Module module)
+    {
+
+        try { synchronized (writeIOSync)
+        {
+            Path dataFile = toPath(module);
+            if (dataFile == null) return false;
+            return Files.deleteIfExists(dataFile);
+        } }
+        catch (IOException e)
+        {
+            throw new ThrowStatement("Error while removing file: "+getDisplayPath(), Throwables.IO_EXCEPTION);
+        }
+        finally
+        {
+            close();
+        }
+    }
+
+    public List<String> listFile(Module module)
+    {
+        try { synchronized (writeIOSync) {
+            Path dataFile = toPath(module);
+            if (dataFile == null) return null;
+            if (!Files.exists(dataFile)) return null;
+            return listFileContent(dataFile);
+        } }
+        finally {
+            close();
+        }
+    }
+
+    public static List<String> listFileContent(Path filePath)
+    {
+        try (BufferedReader reader = Files.newBufferedReader(filePath, StandardCharsets.UTF_8)) {
+            List<String> result = new ArrayList<>();
+            for (;;) {
+                String line = reader.readLine();
+                if (line == null)
+                    break;
+                result.add(line.replaceAll("[\n\r]+",""));
+            }
+            return result;
+        }
+        catch (IOException e)
+        {
+            throw new ThrowStatement("Failed to read text file "+filePath.toString(), Throwables.IO_EXCEPTION);
+        }
+    }
+
+    public JsonElement readJsonFile(Module module) {
+        try { synchronized (writeIOSync) {
+            Path dataFile = toPath(module);
+            if (dataFile == null || !Files.exists(dataFile)) return null;
+            return readJsonContent(dataFile);
+        } }
+        finally {
+            close();
+        }
+    }
+
+    public static JsonElement readJsonContent(Path filePath)
+    {
+        try (BufferedReader reader = Files.newBufferedReader(filePath, StandardCharsets.UTF_8))
+        {
+            return new JsonParser().parse(new JsonReader(reader));
+        }
+        catch (JsonParseException e)
+        {
+            Throwable exc = e;
+            if(e.getCause() != null)
+                exc = e.getCause();
+            throw new ThrowStatement(MapValue.wrap(ImmutableMap.of(
+                    StringValue.of("error"), StringValue.of(exc.getMessage()),
+                    StringValue.of("path"), StringValue.of(filePath.toString())
+            )), Throwables.JSON_ERROR);
+        }
+        catch (IOException e)
+        {
+            throw new ThrowStatement("Failed to read json file content "+filePath.toString(), Throwables.IO_EXCEPTION);
+        }
+    }
+
+}

src/main/java/carpet/script/bundled/FileModule.java

@@ -1,33 +1,10 @@
 package carpet.script.bundled;
 
-import net.minecraft.nbt.CompoundTag;
-import net.minecraft.nbt.NbtIo;
-import net.minecraft.nbt.PositionTracker;
-import net.minecraft.nbt.Tag;
-import net.minecraft.nbt.TagReaders;
-
-import java.io.BufferedReader;
-import java.io.BufferedWriter;
-import java.io.DataInputStream;
-import java.io.DataOutputStream;
-import java.io.File;
-import java.io.FileInputStream;
-import java.io.FileOutputStream;
 import java.io.IOException;
-import java.io.OutputStream;
-import java.io.OutputStreamWriter;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.nio.file.StandardOpenOption;
-import java.util.ArrayList;
-import java.util.List;
 import java.util.Locale;
-import java.util.stream.Stream;
-
-import com.google.gson.JsonElement;
-import com.google.gson.JsonParser;
-import com.google.gson.stream.JsonReader;
 
 public class FileModule extends Module
 {
@@ -66,149 +43,4 @@ public class FileModule extends Module
         return library;
     }
 
-    //copied private method from net.minecraft.nbt.NbtIo.read()
-    // to read non-compound tags - these won't be compressed
-    public static Tag read(File file)
-    {
-        try
-        {
-            return NbtIo.readCompressed(file);
-        }
-        catch (IOException e)
-        {
-            // Copy of NbtIo.read(File) because that's now client-side only
-            if (!file.exists())
-            {
-                return null;
-            }
-            try (DataInputStream in = new DataInputStream(new FileInputStream(file)))
-            {
-                return NbtIo.read(in);
-            }
-            catch (IOException ioException)
-            {
-                try (DataInputStream dataInput_1 = new DataInputStream(new FileInputStream(file)))
-                {
-                    byte byte_1 = dataInput_1.readByte();
-                    if (byte_1 == 0)
-                    {
-                        return null;
-                    }
-                    else
-                    {
-                        dataInput_1.readUTF();
-                        return TagReaders.of(byte_1).read(dataInput_1, 0, PositionTracker.DEFAULT);
-                    }
-                }
-                catch (IOException ignored)
-                {
-                }
-                return null;
-            }
-        }
-    }
-
-    //copied private method from net.minecraft.nbt.NbtIo.write() and client method safe_write
-    public static boolean write(Tag tag_1, File file)
-    {
-        File file_2 = new File(file.getAbsolutePath() + "_tmp");
-        if (file_2.exists()) file_2.delete();
-
-        if (tag_1 instanceof CompoundTag)
-        {
-            try
-            {
-                NbtIo.writeCompressed((CompoundTag) tag_1, file_2);
-            }
-            catch (IOException e)
-            {
-                return false;
-            }
-        }
-        else
-        {
-            try (DataOutputStream dataOutputStream_1 = new DataOutputStream(new FileOutputStream(file_2)))
-            {
-                dataOutputStream_1.writeByte(tag_1.getType());
-                if (tag_1.getType() != 0)
-                {
-                    dataOutputStream_1.writeUTF("");
-                    tag_1.write(dataOutputStream_1);
-                }
-            }
-            catch (IOException e)
-            {
-                return false;
-            }
-        }
-        if (file.exists()) file.delete();
-        if (!file.exists()) file_2.renameTo(file);
-        return true;
-    }
-
-    public static boolean appendText(Path filePath, boolean addNewLines, List<String> data)
-    {
-        try
-        {
-            OutputStream out = Files.newOutputStream(filePath, StandardOpenOption.APPEND, StandardOpenOption.CREATE);
-            try (BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(out, StandardCharsets.UTF_8)))
-            {
-                for (String line: data)
-                {
-                    writer.append(line);
-                    if (addNewLines) writer.newLine();
-                }
-            }
-        }
-        catch (IOException e)
-        {
-            return false;
-        }
-        return true;
-    }
-
-
-    public static List<String> listFileContent(Path filePath)
-    {
-        try (BufferedReader reader = Files.newBufferedReader(filePath, StandardCharsets.UTF_8)) {
-            List<String> result = new ArrayList<>();
-            for (;;) {
-                String line = reader.readLine();
-                if (line == null)
-                    break;
-                result.add(line.replaceAll("[\n\r]+",""));
-            }
-            return result;
-        }
-        catch (IOException e)
-        {
-            return null;
-        }
-    }
-    
-    public static JsonElement readJsonContent(Path filePath)
-    {
-    	try (BufferedReader reader = Files.newBufferedReader(filePath, StandardCharsets.UTF_8))
-        {
-            return new JsonParser().parse(new JsonReader(reader));
-        }
-        catch (IOException e)
-        {
-            return null;
-        }
-    }
-
-    public static Stream<Path> listFiles(Path dir, String ext)
-    {
-        boolean folderListing = ext.equals("folder");
-        try
-        {
-            return Files.list(dir).
-                    filter(path -> folderListing?Files.isDirectory(path):path.toString().endsWith(ext));
-        }
-        catch (IOException ignored)
-        {
-            return null;
-        }
-    }
 }

src/main/java/carpet/script/bundled/Module.java

@@ -1,112 +1,39 @@
 package carpet.script.bundled;
 
 import carpet.CarpetServer;
+import carpet.script.argument.FileArgument;
 import net.minecraft.nbt.Tag;
 import net.minecraft.util.WorldSavePath;
-import org.apache.commons.io.FilenameUtils;
-
-import com.google.common.collect.ImmutableMap;
-import com.google.gson.JsonElement;
 
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.util.List;
-import java.util.Map;
-import java.util.stream.Stream;
 
 public abstract class Module
 {
     public abstract String getName();
     public abstract String getCode();
     public abstract boolean isLibrary();
-    public final static Object writeIOSync = new Object();
-    public final static Map<String, String> supportedTypes = ImmutableMap.of(
-            "raw", ".txt",
-            "text", ".txt",
-            "nbt", ".nbt",
-            "json", ".json",
-            "folder", "folder"
-    );
 
-    private static String getDescriptor(Module module, String file, boolean isShared)
+    public static Tag getData(Module module)
     {
-        if (isShared)
-        {
-            return file.isEmpty()?"shared":"shared/"+file;
-        }
-        if (module != null && module.getName() != null) // appdata
-        {
-            return module.getName()+".data"+(file==null || file.isEmpty()?"":"/"+file);
-        }
-        throw  new RuntimeException("Invalid file descriptor: "+file);
-    }
-
-    public static Tag getData(Module module, String file, boolean isShared)
-    {
-        Path dataFile = resolveResource(module, file, ".nbt", isShared);
+        Path dataFile = resolveResource(module);
         if (dataFile == null) return null;
         if (!Files.exists(dataFile) || !(dataFile.toFile().isFile())) return null;
-        synchronized (writeIOSync) { return FileModule.read(dataFile.toFile()); }
+        synchronized (FileArgument.writeIOSync) { return FileArgument.readTag(dataFile); }
     }
 
-    public static boolean saveData(Module module, String file, Tag globalState, boolean isShared)
+    public static void saveData(Module module, Tag globalState)
     {
-        Path dataFile = resolveResource(module, file, ".nbt", isShared);
-        if (dataFile == null) return false;
-        if (!Files.exists(dataFile.getParent()) && !dataFile.toFile().getParentFile().mkdirs()) return false;
-        synchronized (writeIOSync) { return FileModule.write(globalState, dataFile.toFile()); }
+        Path dataFile = resolveResource(module);
+        if (dataFile == null) return;
+        if (!Files.exists(dataFile.getParent()) && !dataFile.toFile().getParentFile().mkdirs()) return;
+        synchronized (FileArgument.writeIOSync) { FileArgument.writeTagDisk(globalState, dataFile, false); }
     }
 
-    public static boolean appendToTextFile(Module module, String resourceName, String type, boolean isShared, List<String> message)
+    private static Path resolveResource(Module module)
     {
-        Path dataFile = resolveResource(module, resourceName, supportedTypes.get(type), isShared);
-        if (dataFile == null) return false;
-        if (!Files.exists(dataFile.getParent()) && !dataFile.toFile().getParentFile().mkdirs()) return false;
-        synchronized (writeIOSync) { return FileModule.appendText(dataFile, type.equals("text"), message); }
-    }
-
-    public static boolean dropExistingFile(Module module, String resourceName, String type, boolean isShared)
-    {
-        Path dataFile = resolveResource(module, resourceName, supportedTypes.get(type), isShared);
-        if (dataFile == null) return false;
-        synchronized (writeIOSync) { return dataFile.toFile().delete(); }
-    }
-
-    public static List<String> listFile(Module module, String resourceName, String type, boolean isShared)
-    {
-        Path dataFile = resolveResource(module, resourceName, supportedTypes.get(type), isShared);
-        if (dataFile == null) return null;
-        if (!dataFile.toFile().exists()) return null;
-        synchronized (writeIOSync) { return FileModule.listFileContent(dataFile); }
-    }
-    
-    public static JsonElement readJsonFile(Module module, String resourceName, String type, boolean isShared) {
-        Path dataFile = resolveResource(module, resourceName, supportedTypes.get(type), isShared);
-        if (dataFile == null) return null;
-        if (!dataFile.toFile().exists()) return null;
-        synchronized (writeIOSync) { return FileModule.readJsonContent(dataFile); }
-    }
-
-    public static Stream<String> listFolder(Module module, String resourceName, String type, boolean isShared)
-    {
-        Path dir = resolveResource(module, resourceName, null, isShared);
-        String ext = supportedTypes.get(type);
-        if (dir == null) return null;
-        if (!Files.exists(dir)) return null;
-        Stream<Path> result;
-        synchronized (writeIOSync) { result = FileModule.listFiles(dir, ext); }
-        if (result == null) return null;
-        Path rootPath = resolveResource(module, "", null, isShared);
-        Stream<String> strings = result.map(p -> rootPath.relativize(p).toString().replaceAll("[\\\\/]","/"));
-        if (!ext.equals("folder"))
-            return strings.map(FilenameUtils::removeExtension);
-        return strings;
-    }
-
-    private static Path resolveResource(Module module, String resourceName, String ext, boolean isShared)
-    {
-        if (!isShared && (module == null || module.getName() == null)) return null;
-        return CarpetServer.minecraft_server.getSavePath(WorldSavePath.ROOT).resolve("scripts/"+getDescriptor(module, resourceName, isShared)+(ext==null?"":ext));
+        if (module == null || module.getName() == null) return null; // commandline app
+        return CarpetServer.minecraft_server.getSavePath(WorldSavePath.ROOT).resolve("scripts/"+module.getName()+".data.nbt");
     }
 
     @Override

src/main/java/carpet/script/command/CommandArgument.java

@@ -1,5 +1,6 @@
 package carpet.script.command;
 
+import carpet.CarpetServer;
 import carpet.fakes.BlockStateArgumentInterface;
 import carpet.script.CarpetScriptHost;
 import carpet.script.argument.FunctionArgument;
@@ -14,6 +15,7 @@ import carpet.script.value.NumericValue;
 import carpet.script.value.StringValue;
 import carpet.script.value.Value;
 import carpet.script.value.ValueConversions;
+import carpet.utils.CarpetProfiler;
 import com.google.common.collect.Lists;
 import com.mojang.authlib.GameProfile;
 import com.mojang.brigadier.arguments.ArgumentType;
@@ -276,7 +278,12 @@ public abstract class CommandArgument
     {
         CommandArgument arg = getTypeForArgument(param, host);
         if (arg.suggestionProvider != null) return argument(param, arg.getArgumentType()).suggests(arg.suggestionProvider);
-        return arg.needsMatching? argument(param, arg.getArgumentType()).suggests((c, b) -> arg.suggest(c, b, host)) : argument(param, arg.getArgumentType());
+        if (!arg.needsMatching) return argument(param, arg.getArgumentType());
+        String hostName = host.getName();
+        return argument(param, arg.getArgumentType()).suggests((ctx, b) -> {
+            CarpetScriptHost cHost = CarpetServer.scriptServer.modules.get(hostName).retrieveOwnForExecution(ctx.getSource());
+            return arg.suggest(ctx, b, cHost);
+        });
     }
 
     protected String suffix;
@@ -365,6 +372,7 @@ public abstract class CommandArgument
     {
         if (customSuggester != null)
         {
+            CarpetProfiler.ProfilerToken currentSection = CarpetProfiler.start_section(null, "Scarpet command", CarpetProfiler.TYPE.GENERAL);
             Map<Value, Value> params = new HashMap<>();
             for(ParsedCommandNode<ServerCommandSource> pnode : context.getNodes())
             {
@@ -379,7 +387,9 @@ public abstract class CommandArgument
             args.addAll(customSuggester.args);
             Value response = host.handleCommand(context.getSource(), customSuggester.function, args);
             if (!(response instanceof ListValue)) throw error("Custom suggester should return a list of options"+" for custom type "+suffix);
-            return ((ListValue) response).getItems().stream().map(Value::getString).collect(Collectors.toList());
+            Collection<String> res = ((ListValue) response).getItems().stream().map(Value::getString).collect(Collectors.toList());
+            CarpetProfiler.end_current_section(currentSection);
+            return res;
         }
         if (needsMatching) return examples;
         //return Lists.newArrayList("");

src/main/java/carpet/script/exception/ExpressionException.java

@@ -7,29 +7,43 @@ import carpet.script.Tokenizer;
 import carpet.script.value.FunctionValue;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
+import java.util.function.Supplier;
 
 /* The expression evaluators exception class. */
 public class ExpressionException extends RuntimeException implements ResolvedException
 {
     public final Context context;
+    public final Tokenizer.Token token;
     public final List<FunctionValue> stack = new ArrayList<>();
+    private final Supplier<String> lazyMessage;
+    private String cachedMessage = null;
 
     public ExpressionException(Context c, Expression e, String message)
     {
-        super(makeMessage(c, e, null, message));
-        context = c;
+        this(c, e, Tokenizer.Token.NONE, message);
     }
 
     public ExpressionException(Context c, Expression e, Tokenizer.Token t, String message)
     {
-        super(makeMessage(c, e, t, message));
-        context = c;
+        this(c, e, t, message, Collections.emptyList());
     }
     public ExpressionException(Context c, Expression e, Tokenizer.Token t, String message, List<FunctionValue> stack)
     {
-        super(makeMessage(c, e, t, message));
+        super("Error");
         this.stack.addAll(stack);
+        lazyMessage = () -> makeMessage(c, e, t, message);
+        token = t;
+        context = c;
+    }
+
+    public ExpressionException(Context c, Expression e, Tokenizer.Token t, Supplier<String> messageSupplier, List<FunctionValue> stack)
+    {
+        super("Error");
+        this.stack.addAll(stack);
+        lazyMessage = () -> makeMessage(c, e, t, messageSupplier.get());
+        token = t;
         context = c;
     }
 
@@ -68,4 +82,13 @@ public class ExpressionException extends RuntimeException implements ResolvedExc
         }
         return String.join("\n", errorMaker.apply(e, t, message));
     }
+    
+    @Override
+    public String getMessage() {
+        if (cachedMessage == null)
+        {
+        	cachedMessage = lazyMessage.get();
+        }
+        return cachedMessage;
+    }
 }

src/main/java/carpet/script/exception/InternalExpressionException.java

@@ -1,5 +1,8 @@
 package carpet.script.exception;
 
+import carpet.script.Context;
+import carpet.script.Expression;
+import carpet.script.Tokenizer;
 import carpet.script.value.FunctionValue;
 
 import java.util.ArrayList;
@@ -13,4 +16,20 @@ public class InternalExpressionException extends RuntimeException
     {
         super(message);
     }
+    
+    /**
+     * <p>Promotes this simple exception into one with context and extra information.
+     * 
+     * <p>Provides a cleaner way of handling similar exceptions, in this case
+     * {@link InternalExpressionException} and {@link ThrowStatement} 
+     * @param c Context
+     * @param e Expression
+     * @param token Token
+     * @return The new {@link ExpressionException} (or {@link ProcessedThrowStatement}),
+     *         depending on the implementation.
+     */
+    public ExpressionException promote(Context c, Expression e, Tokenizer.Token token)
+    {
+        return new ExpressionException(c, e, token, getMessage(), stack);
+    }
 }

src/main/java/carpet/script/exception/ProcessedThrowStatement.java

@@ -0,0 +1,20 @@
+package carpet.script.exception;
+
+import java.util.List;
+
+import carpet.script.Context;
+import carpet.script.Expression;
+import carpet.script.Tokenizer.Token;
+import carpet.script.value.FunctionValue;
+import carpet.script.value.Value;
+
+public class ProcessedThrowStatement extends ExpressionException {
+    public final Throwables thrownExceptionType;
+    public final Value data;
+    
+    public ProcessedThrowStatement(Context c, Expression e, Token token, List<FunctionValue> stack, Throwables thrownExceptionType, Value data) {
+        super(c, e, token, ()  -> "Unhandled "+thrownExceptionType.getId()+" exception: "+data.getString(), stack);
+        this.thrownExceptionType = thrownExceptionType;
+        this.data = data;
+    }
+}

src/main/java/carpet/script/exception/ThrowStatement.java

@@ -1,11 +1,54 @@
 package carpet.script.exception;
 
+import carpet.script.Context;
+import carpet.script.Expression;
+import carpet.script.Tokenizer.Token;
+import carpet.script.value.StringValue;
 import carpet.script.value.Value;
 
-public class ThrowStatement extends ExitStatement
+public class ThrowStatement extends InternalExpressionException
 {
-    public ThrowStatement(Value value)
+    private final Throwables type;
+    private final Value data;
+    
+    /**
+     * Creates a throw exception from a value, and assigns it a specified message.
+     * <p>To be used when throwing from Scarpet's {@code throw} function
+     * @param data The value to pass
+     * @param type Exception type
+     */
+    public ThrowStatement(Value data, Throwables type)
     {
-        super(value);
+        super(type.getId());
+        this.data = data;
+        this.type = type;
+    }
+
+    public ThrowStatement(Value data, Throwables parent, String subtype)
+    {
+        super(subtype);
+        this.data = data;
+        this.type = new Throwables(subtype, parent);
+    }
+
+    /**
+     * Creates a throw exception.<br>
+     * Conveniently creates a value from the {@code value} String
+     * to be used easily in Java code
+     * @param message The message to display when not handled
+     * @param type An {@link Throwables} containing the inheritance data
+     *                  for this exception. When throwing from Java,
+     *                  those exceptions should be pre-registered.
+     */
+    public ThrowStatement(String message, Throwables type)
+    {
+        super(type.getId());
+        this.data = StringValue.of(message);
+        this.type = type;
+    }
+    
+    @Override
+    public ExpressionException promote(Context c, Expression e, Token token) {
+        return new ProcessedThrowStatement(c, e, token, stack, type, data);
     }
 }

src/main/java/carpet/script/exception/Throwables.java

@@ -0,0 +1,89 @@
+package carpet.script.exception;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * This class contains default Scarpet catchable types, as well as their inheritance and
+ * methods to check whether filters are compatible with those.
+ */
+public class Throwables {
+    private final String id;
+    private final Throwables parent;
+
+    private static final Map<String, Throwables> byId = new HashMap<>();
+
+    public static final Throwables THROWN_EXCEPTION_TYPE = register("exception", null);
+    public static final Throwables VALUE_EXCEPTION       = register("value_exception", THROWN_EXCEPTION_TYPE);
+    public static final Throwables UNKNOWN_ITEM          = register("unknown_item", VALUE_EXCEPTION);
+    public static final Throwables UNKNOWN_BLOCK         = register("unknown_block", VALUE_EXCEPTION);
+    public static final Throwables UNKNOWN_BIOME         = register("unknown_biome", VALUE_EXCEPTION);
+    public static final Throwables UNKNOWN_SOUND         = register("unknown_sound", VALUE_EXCEPTION);
+    public static final Throwables UNKNOWN_PARTICLE      = register("unknown_particle", VALUE_EXCEPTION);
+    public static final Throwables UNKNOWN_POI           = register("unknown_poi", VALUE_EXCEPTION);
+    public static final Throwables UNKNOWN_DIMENSION     = register("unknown_dimension", VALUE_EXCEPTION);
+    public static final Throwables UNKNOWN_STRUCTURE     = register("unknown_structure", VALUE_EXCEPTION);
+    public static final Throwables UNKNOWN_CRITERION     = register("unknown_criterion", VALUE_EXCEPTION);
+    public static final Throwables IO_EXCEPTION          = register("io_exception", THROWN_EXCEPTION_TYPE);
+    public static final Throwables NBT_ERROR             = register("nbt_error", IO_EXCEPTION);
+    public static final Throwables JSON_ERROR            = register("json_error", IO_EXCEPTION);
+    public static final Throwables USER_DEFINED          = register("user_exception", THROWN_EXCEPTION_TYPE);
+
+    /**
+     * Creates an exception and registers it to be used as parent for
+     * user defined exceptions in Scarpet's throw function.
+     * <p>Scarpet exceptions should have a top-level parent being {@link Throwables#THROWN_EXCEPTION_TYPE}
+     * @param id The value for the exception as a {@link String}.
+     * @param parent The parent of the exception being created, or <code>null</code> if top-level
+     * @return The created exception
+     */
+    public static Throwables register(String id, Throwables parent)
+    {
+        Throwables exc = new Throwables(id, parent);
+        byId.put(id, exc);
+        return exc;
+    }
+
+    /**
+     * Creates a new exception.
+     * <p>Not suitable for creating exceptions that can't be caught.
+     * Use an {@link InternalExpressionException} for that
+     * @param id The exception's value as a {@link String}
+     */
+    public Throwables(String id, Throwables parent)
+    {
+        this.id = id;
+        this.parent = parent;
+    }
+
+    public static Throwables getTypeForException(String type)
+    {
+        Throwables properType = byId.get(type);
+        if (properType == null) throw new InternalExpressionException("Unknown exception type: "+type);
+        return properType;
+    }
+
+    /**
+     * Checks whether the given filter matches an instance of this exception, by checking equality
+     * with itself and possible parents.
+     * @param filter The type to check against
+     * @return Whether or not the given value matches this exception's hierarchy
+     */
+    public boolean isRelevantFor(String filter)
+    {
+        return (id.equals(filter) || (parent != null && parent.isRelevantFor(filter)));
+    }
+
+    public boolean isUserException()
+    {
+        return this == USER_DEFINED || parent == USER_DEFINED;
+    }
+
+    /**
+     * Returns the throwable type
+     * @return The type of this exception
+     */
+    public String getId() {
+        return id;
+    }
+}

src/main/java/carpet/script/language/Arithmetic.java

@@ -60,9 +60,9 @@ public class Arithmetic {
         expression.addMathematicalUnaryFunction("log1p", x -> Math.log1p(x)/Math.log(2));
         expression.addMathematicalUnaryFunction("sqrt", Math::sqrt);
         expression.addMathematicalUnaryFunction("abs", Math::abs);
-        expression.addMathematicalUnaryFunction("round", (d) -> (double)Math.round(d));
-        expression.addMathematicalUnaryFunction("floor", Math::floor);
-        expression.addMathematicalUnaryFunction("ceil", Math::ceil);
+        expression.addMathematicalUnaryIntFunction("round", Math::round);
+        expression.addMathematicalUnaryIntFunction("floor", n -> (long)Math.floor(n));
+        expression.addMathematicalUnaryIntFunction("ceil",  n -> (long)Math.ceil(n));
 
         expression.addLazyFunction("mandelbrot", 3, (c, t, lv) -> {
             double a0 = NumericValue.asNumber(lv.get(0).evalValue(c)).getDouble();

src/main/java/carpet/script/language/ControlFlow.java

@@ -5,8 +5,17 @@ import carpet.script.Expression;
 import carpet.script.LazyValue;
 import carpet.script.exception.ExitStatement;
 import carpet.script.exception.InternalExpressionException;
+import carpet.script.exception.ProcessedThrowStatement;
 import carpet.script.exception.ThrowStatement;
+import carpet.script.exception.Throwables;
+import carpet.script.value.ListValue;
+import carpet.script.value.MapValue;
+import carpet.script.value.NumericValue;
+import carpet.script.value.StringValue;
 import carpet.script.value.Value;
+import com.google.common.collect.ImmutableMap;
+
+import java.util.stream.Collectors;
 
 public class ControlFlow {
     public static void apply(Expression expression) // public just to get the javadoc right
@@ -42,26 +51,98 @@ public class ControlFlow {
 
         expression.addFunction("exit", (lv) -> { throw new ExitStatement(lv.size()==0?Value.NULL:lv.get(0)); });
 
-        expression.addFunction("throw", (lv)-> {throw new ThrowStatement(lv.size()==0?Value.NULL:lv.get(0)); });
+        expression.addLazyFunction("throw", -1, (c, t, lv)-> 
+        {
+            switch (lv.size()) 
+            {
+                case 0:
+                    throw new ThrowStatement(Value.NULL, Throwables.USER_DEFINED);
+                case 1:
+                    throw new ThrowStatement(lv.get(0).evalValue(c), Throwables.USER_DEFINED );
+                case 2:
+                    throw new ThrowStatement(lv.get(1).evalValue(c), Throwables.getTypeForException(lv.get(0).evalValue(c).getString()));
+                case 3:
+                    throw new ThrowStatement(lv.get(2).evalValue(c), Throwables.getTypeForException(lv.get(1).evalValue(c).getString()), lv.get(0).evalValue(c).getString());
+                default:
+                    throw new InternalExpressionException("throw() can't accept more than 3 parameters");
+            }
+        });
 
         expression.addLazyFunction("try", -1, (c, t, lv) ->
         {
             if (lv.size()==0)
-                throw new InternalExpressionException("'try' needs at least an expression block");
+                throw new InternalExpressionException("'try' needs at least an expression block, and either a catch_epr, or a number of pairs of filters and catch_expr");
             try
             {
                 Value retval = lv.get(0).evalValue(c, t);
                 return (c_, t_) -> retval;
             }
-            catch (ThrowStatement ret)
+            catch (ProcessedThrowStatement ret)
             {
                 if (lv.size() == 1)
+                {
+                    if (!ret.thrownExceptionType.isUserException())
+                        throw ret;
                     return (c_, t_) -> Value.NULL;
+                }
+                if (lv.size() > 3 && lv.size() % 2 == 0)
+                {
+                    throw new InternalExpressionException("Try-catch block needs the code to run, and either a catch expression for user thrown exceptions, or a number of pairs of filters and catch expressions");
+                }
+                
+                Value val = null; // This is always assigned at some point, just the compiler doesn't know
+                
                 LazyValue __ = c.getVariable("_");
-                c.setVariable("_", (__c, __t) -> ret.retval.reboundedTo("_"));
-                Value val = lv.get(1).evalValue(c, t);
-                c.setVariable("_",__);
-                return (c_, t_) -> val;
+                c.setVariable("_", (__c, __t) -> ret.data.reboundedTo("_"));
+                LazyValue _trace = c.getVariable("_trace");
+                c.setVariable("_trace", (__c, __t) -> MapValue.wrap(ImmutableMap.of(
+                        StringValue.of("stack"), ListValue.wrap(ret.stack.stream().map(f -> ListValue.of(
+                                StringValue.of(f.getModule().getName()),
+                                StringValue.of(f.getString()),
+                                NumericValue.of(f.getToken().lineno+1),
+                                NumericValue.of(f.getToken().linepos+1)
+                        )).collect(Collectors.toList())),
+
+                        StringValue.of("locals"), MapValue.wrap(ret.context.variables.entrySet().stream().filter(e -> !e.getKey().equals("_trace")).collect(Collectors.toMap(
+                                e -> StringValue.of(e.getKey()),
+                                e -> e.getValue().evalValue(ret.context)
+                        ))),
+                        StringValue.of("token"), ListValue.of(
+                                StringValue.of(ret.token.surface),
+                                NumericValue.of(ret.token.lineno+1),
+                                NumericValue.of(ret.token.linepos+1)
+                        )
+                )));
+
+                if (lv.size() == 2)
+                {
+                    if (ret.thrownExceptionType.isUserException())
+                        val = lv.get(1).evalValue(c, t);
+                }
+                else
+                {
+                    int pointer = 1;
+                    while (pointer < lv.size() -1)
+                    {
+                        if (ret.thrownExceptionType.isRelevantFor(lv.get(pointer).evalValue(c).getString()))
+                        {
+                            val = lv.get(pointer + 1).evalValue(c, t);
+                            break;
+                        }
+                        pointer += 2;
+                    }
+                }
+                c.setVariable("_", __);
+                if (_trace != null)
+                    c.setVariable("_trace", _trace);
+                else
+                    c.delVariable("_trace");
+                if (val == null)  // not handled
+                {
+                    throw ret;
+                }
+                Value retval = val;
+                return (c_, t_) -> retval;
             }
         });
     }

src/main/java/carpet/script/language/Loops.java

@@ -119,7 +119,7 @@ public class Loops {
                 c.setVariable("_i", (cc, tt) -> new NumericValue(doYouReally).bindTo("_i"));
                 try
                 {
-                    result.add(expr.evalValue(c));
+                    result.add(expr.evalValue(c, t));
                 }
                 catch (BreakStatement | ContinueStatement stmt)
                 {

src/main/java/carpet/script/language/Sys.java

@@ -48,7 +48,7 @@ public class Sys {
                     return (cc, tt) -> Value.FALSE;
                 }
             }
-            Value retval = new NumericValue(v.getBoolean());
+            Value retval = v.getBoolean()?Value.TRUE:Value.FALSE;
             return (cc, tt) -> retval;
         });
 
@@ -56,7 +56,9 @@ public class Sys {
         {
             if (v instanceof NumericValue)
             {
-                return v;
+                NumericValue num = (NumericValue)v;
+                if (num.isInteger()) return new NumericValue(num.getLong());
+                return new NumericValue(num.getDouble());
             }
             try
             {
@@ -208,6 +210,10 @@ public class Sys {
             Value retval = new NumericValue(NumericValue.asNumber(argument).getDouble()*randomizer.nextDouble());
             return (cc, tt) -> retval;
         });
+        expression.addLazyFunction("reset_seed", 1, (c, t, lv) -> {
+            boolean gotIt = c.host.resetRandom(NumericValue.asNumber(lv.get(0).evalValue(c)).getLong());
+            return gotIt?LazyValue.TRUE:LazyValue.FALSE;
+        });
 
         expression.addLazyFunction("perlin", -1, (c, t, lv) ->
         {

src/main/java/carpet/script/utils/InputValidator.java

@@ -0,0 +1,16 @@
+package carpet.script.utils;
+
+import carpet.script.exception.InternalExpressionException;
+
+import java.util.Locale;
+
+public class InputValidator {
+    public static String validateSimpleString(String input, boolean strict)
+    {
+        String simplified = input.toLowerCase(Locale.ROOT).replaceAll("[^A-Za-z0-9+_]", "");
+        if (simplified.isEmpty() || (strict && !simplified.equals(input)))
+            throw new InternalExpressionException("simple name can only contain numbers, letter and _");
+        return simplified;
+    }
+
+}

src/main/java/carpet/script/utils/ShapeDispatcher.java

@@ -4,6 +4,8 @@ import carpet.CarpetSettings;
 import carpet.network.ServerNetworkHandler;
 import carpet.script.CarpetContext;
 import carpet.script.exception.InternalExpressionException;
+import carpet.script.exception.ThrowStatement;
+import carpet.script.exception.Throwables;
 import carpet.script.language.Sys;
 import carpet.script.value.BlockValue;
 import carpet.script.value.EntityValue;
@@ -156,7 +158,7 @@ public class ShapeDispatcher
         }
         catch (CommandSyntaxException e)
         {
-            throw new InternalExpressionException("No such particle: "+name);
+            throw new ThrowStatement(name, Throwables.UNKNOWN_PARTICLE);
         }
         particleCache.put(name, particle);
         return particle;
@@ -416,6 +418,8 @@ public class ShapeDispatcher
                 put("facing", new StringValue("player")).
                 put("raise", new NumericValue(0)).
                 put("tilt", new NumericValue(0)).
+                put("lean", new NumericValue(0)).
+                put("turn", new NumericValue(0)).
                 put("indent", new NumericValue(0)).
                 put("height", new NumericValue(0)).
                 put("align", new StringValue("center")).
@@ -437,6 +441,8 @@ public class ShapeDispatcher
         Direction facing;
         float raise;
         float tilt;
+        float lean;
+        float turn;
         float size;
         float indent;
         int align;
@@ -485,6 +491,8 @@ public class ShapeDispatcher
 
             raise = NumericValue.asNumber(options.getOrDefault("raise", optional.get("raise"))).getFloat();
             tilt = NumericValue.asNumber(options.getOrDefault("tilt", optional.get("tilt"))).getFloat();
+            lean = NumericValue.asNumber(options.getOrDefault("lean", optional.get("lean"))).getFloat();
+            turn = NumericValue.asNumber(options.getOrDefault("turn", optional.get("turn"))).getFloat();
             indent = NumericValue.asNumber(options.getOrDefault("indent", optional.get("indent"))).getFloat();
             height = NumericValue.asNumber(options.getOrDefault("height", optional.get("height"))).getFloat();
 
@@ -517,6 +525,8 @@ public class ShapeDispatcher
             if (facing!= null) hash ^= facing.hashCode(); hash *= 1099511628211L;
             hash ^= Float.hashCode(raise); hash *= 1099511628211L;
             hash ^= Float.hashCode(tilt); hash *= 1099511628211L;
+            hash ^= Float.hashCode(lean); hash *= 1099511628211L;
+            hash ^= Float.hashCode(turn); hash *= 1099511628211L;
             hash ^= Float.hashCode(indent); hash *= 1099511628211L;
             hash ^= Float.hashCode(height); hash *= 1099511628211L;
             hash ^= Float.hashCode(size); hash *= 1099511628211L;

src/main/java/carpet/script/utils/ShapesRenderer.java

@@ -1,6 +1,7 @@
 package carpet.script.utils;
 
 import carpet.CarpetSettings;
+import carpet.utils.CarpetProfiler;
 import com.mojang.blaze3d.systems.RenderSystem;
 import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
 import net.minecraft.client.MinecraftClient;
@@ -49,6 +50,7 @@ public class ShapesRenderer
 
     public void render(Camera camera, float partialTick)
     {
+        CarpetProfiler.ProfilerToken token = CarpetProfiler.start_section(null, "Scarpet client", CarpetProfiler.TYPE.GENERAL);
         //Camera camera = this.client.gameRenderer.getCamera();
         ClientWorld iWorld = this.client.world;
         RegistryKey<World> dimensionType = iWorld.getRegistryKey();
@@ -120,14 +122,17 @@ public class ShapesRenderer
         RenderSystem.defaultBlendFunc();
         RenderSystem.enableTexture();
         RenderSystem.shadeModel(7424);
+        CarpetProfiler.end_current_section(token);
     }
 
     public void addShapes(ListTag tag)
     {
+        CarpetProfiler.ProfilerToken token = CarpetProfiler.start_section(null, "Scarpet client", CarpetProfiler.TYPE.GENERAL);
         for (int i=0, count = tag.size(); i < count; i++)
         {
             addShape(tag.getCompound(i));
         }
+        CarpetProfiler.end_current_section(token);
     }
 
     public void addShape(CompoundTag tag)
@@ -169,12 +174,14 @@ public class ShapesRenderer
 
     public void renewShapes()
     {
+        CarpetProfiler.ProfilerToken token = CarpetProfiler.start_section(null, "Scarpet client", CarpetProfiler.TYPE.GENERAL);
         synchronized (shapes)
         {
             shapes.values().forEach(el -> el.values().forEach(shape -> {
                 shape.expiryTick++;
             }));
         }
+        CarpetProfiler.end_current_section(token);
     }
 
     public abstract static class RenderedShape<T extends ShapeDispatcher.ExpiringShape>
@@ -278,6 +285,14 @@ public class ShapesRenderer
             {
                 RenderSystem.rotatef(shape.tilt, 0.0f, 0.0f, 1.0f);
             }
+            if (shape.lean!=0.0f)
+            {
+                RenderSystem.rotatef(shape.lean, 1.0f, 0.0f, 0.0f);
+            }
+            if (shape.turn!=0.0f)
+            {
+                RenderSystem.rotatef(shape.turn, 0.0f, 1.0f, 0.0f);
+            }
             RenderSystem.translatef(-10*shape.indent, -10*shape.height-9, (float) (-10*renderEpsilon)-10*shape.raise);
             //if (visibleThroughWalls) RenderSystem.disableDepthTest();
             RenderSystem.scalef(-1.0F, 1.0F, 1.0F);

src/main/java/carpet/script/utils/SystemInfo.java

@@ -4,11 +4,13 @@ import carpet.CarpetServer;
 import carpet.CarpetSettings;
 import carpet.script.CarpetContext;
 import carpet.script.CarpetScriptHost;
+import carpet.script.value.BooleanValue;
 import carpet.script.value.ListValue;
 import carpet.script.value.MapValue;
 import carpet.script.value.NumericValue;
 import carpet.script.value.StringValue;
 import carpet.script.value.Value;
+import carpet.script.value.ValueConversions;
 import carpet.settings.ParsedRule;
 import carpet.settings.SettingsManager;
 import com.sun.management.OperatingSystemMXBean;
@@ -16,6 +18,7 @@ import net.fabricmc.loader.api.FabricLoader;
 import net.minecraft.SharedConstants;
 import net.minecraft.util.WorldSavePath;
 import net.minecraft.world.GameRules;
+import net.minecraft.world.WorldProperties;
 
 import java.lang.management.ManagementFactory;
 import java.nio.file.Path;
@@ -49,6 +52,12 @@ public class SystemInfo {
             String tlf = serverPath.getName(nodeCount-2).toString();
             return StringValue.of(tlf);
         });
+        put("world_dimensions", c -> ListValue.wrap(c.s.getMinecraftServer().getWorldRegistryKeys().stream().map(k -> ValueConversions.of(k.getValue())).collect(Collectors.toList())));
+        put("world_spawn_point", c -> {
+            WorldProperties prop = c.s.getMinecraftServer().getOverworld().getLevelProperties();
+            return ListValue.of(NumericValue.of(prop.getSpawnX()), NumericValue.of(prop.getSpawnY()), NumericValue.of(prop.getSpawnZ()));
+        });
+
         put("game_difficulty", c -> StringValue.of(c.s.getMinecraftServer().getSaveProperties().getDifficulty().getName()));
         put("game_hardcore", c -> new NumericValue(c.s.getMinecraftServer().getSaveProperties().isHardcore()));
         put("game_storage_format", c -> StringValue.of(c.s.getMinecraftServer().getSaveProperties().getFormatName(c.s.getMinecraftServer().getSaveProperties().getVersion())));
@@ -57,7 +66,19 @@ public class SystemInfo {
         put("game_view_distance", c -> new NumericValue(c.s.getMinecraftServer().getPlayerManager().getViewDistance()));
         put("game_mod_name", c -> StringValue.of(c.s.getMinecraftServer().getServerModName()));
         put("game_version", c -> StringValue.of(c.s.getMinecraftServer().getVersion()));
+        put("game_target", c -> StringValue.of(SharedConstants.getGameVersion().getReleaseTarget()));
+        put("game_protocol", c -> NumericValue.of(SharedConstants.method_31372()));
+        put("game_major_target", c -> {
+            String [] vers = SharedConstants.getGameVersion().getReleaseTarget().split("\\.");
+            return NumericValue.of((vers.length > 1)?Integer.parseInt(vers[1]):0);
+        });
+        put("game_minor_target", c -> {
+            String [] vers = SharedConstants.getGameVersion().getReleaseTarget().split("\\.");
+            return NumericValue.of((vers.length > 2)?Integer.parseInt(vers[2]):0);
+        });
+        put("game_stable", c -> BooleanValue.of(SharedConstants.getGameVersion().isStable()));
         put("game_data_version", c->NumericValue.of(SharedConstants.getGameVersion().getWorldVersion()));
+        put("game_pack_version", c->NumericValue.of(SharedConstants.getGameVersion().getPackVersion()));
 
         put("server_ip", c -> StringValue.of(c.s.getMinecraftServer().getServerIp()));
         put("server_whitelisted", c -> new NumericValue(c.s.getMinecraftServer().isEnforceWhitelist()));

src/main/java/carpet/script/utils/WorldTools.java

@@ -157,5 +157,5 @@ public class WorldTools
         @Override public void stop() { }
     }
 
-    private static final WorldGenerationProgressListener NOOP_LISTENER = new NoopWorldGenerationProgressListener();
+    public static final WorldGenerationProgressListener NOOP_LISTENER = new NoopWorldGenerationProgressListener();
 }

src/main/java/carpet/script/value/BlockValue.java

@@ -2,6 +2,9 @@ package carpet.script.value;
 
 import carpet.script.CarpetContext;
 import carpet.script.exception.InternalExpressionException;
+import carpet.script.exception.ThrowStatement;
+import carpet.script.exception.Throwables;
+
 import com.mojang.brigadier.StringReader;
 import com.mojang.brigadier.exceptions.CommandSyntaxException;
 import net.minecraft.block.BlockState;
@@ -73,7 +76,7 @@ public class BlockValue extends Value
         catch (CommandSyntaxException ignored)
         {
         }
-        throw new InternalExpressionException("Cannot parse block: "+str);
+        throw new ThrowStatement(str, Throwables.UNKNOWN_BLOCK);
     }
 
     public static BlockPos locateBlockPos(CarpetContext c, int xpos, int ypos, int zpos)

src/main/java/carpet/script/value/BooleanValue.java

@@ -0,0 +1,63 @@
+package carpet.script.value;
+
+import com.google.gson.JsonElement;
+import com.google.gson.JsonPrimitive;
+import net.minecraft.nbt.ByteTag;
+import net.minecraft.nbt.Tag;
+
+public class BooleanValue extends NumericValue
+{
+    public static final BooleanValue FALSE = new BooleanValue(false);
+    public static final BooleanValue TRUE = new BooleanValue(true);
+
+    boolean boolValue;
+    private BooleanValue(boolean boolval) {
+        super(boolval);
+        boolValue = boolval;
+    }
+
+    public static BooleanValue of(boolean value)
+    {
+        return value?TRUE:FALSE;
+    }
+
+    @Override
+    public String getString() {
+        return boolValue?"true":"false";
+    }
+
+    @Override
+    public String getPrettyString() {
+        return getString();
+    }
+
+    @Override
+    public String getTypeString() {
+        return "bool";
+    }
+
+    @Override
+    public Value clone() {
+        return new BooleanValue(boolValue);
+    }
+
+    @Override
+    public int hashCode() {
+        return Boolean.hashCode(boolValue);
+    }
+
+    @Override
+    public Tag toTag(boolean force) {
+        return ByteTag.of(boolValue);
+    }
+
+    @Override
+    public JsonElement toJson() {
+        return new JsonPrimitive(boolValue);
+    }
+
+    @Override
+    public boolean isInteger() {
+        return true;
+    }
+}

src/main/java/carpet/script/value/EntityValue.java

@@ -56,6 +56,7 @@ import net.minecraft.server.command.ServerCommandSource;
 import net.minecraft.server.network.ServerPlayerEntity;
 import net.minecraft.server.world.ServerWorld;
 import net.minecraft.text.LiteralText;
+import net.minecraft.util.Hand;
 import net.minecraft.util.Identifier;
 import net.minecraft.util.hit.BlockHitResult;
 import net.minecraft.util.hit.EntityHitResult;
@@ -98,6 +99,12 @@ public class EntityValue extends Value
         entity = e;
     }
 
+    public static Value of(Entity e)
+    {
+        if (e == null) return Value.NULL;
+        return new EntityValue(e);
+    }
+
     private static final Map<String, EntitySelector> selectorCache = new HashMap<>();
     public static Collection<? extends Entity > getEntitiesFromSelector(ServerCommandSource source, String selector)
     {
@@ -416,7 +423,7 @@ public class EntityValue extends Value
         put("motion_z", (e, a) -> new NumericValue(e.getVelocity().z));
         put("on_ground", (e, a) -> new NumericValue(e.isOnGround()));
         put("name", (e, a) -> new StringValue(e.getName().getString()));
-        put("display_name", (e, a) -> new StringValue(e.getDisplayName().getString()));
+        put("display_name", (e, a) -> new FormattedTextValue(e.getDisplayName()));
         put("command_name", (e, a) -> new StringValue(e.getEntityName()));
         put("custom_name", (e, a) -> e.hasCustomName()?new StringValue(e.getCustomName().getString()):Value.NULL);
         put("type", (e, a) -> new StringValue(nameFromRegistryId(Registry.ENTITY_TYPE.getId(e.getType()))));
@@ -429,7 +436,7 @@ public class EntityValue extends Value
         put("tags", (e, a) -> ListValue.wrap(e.getScoreboardTags().stream().map(StringValue::new).collect(Collectors.toList())));
 
         put("scoreboard_tags", (e, a) -> ListValue.wrap(e.getScoreboardTags().stream().map(StringValue::new).collect(Collectors.toList())));
-        put("entity_tags", (e, a) -> ListValue.wrap(e.getServer().getTagManager().getEntityTypes().getTagsFor(e.getType()).stream().map(ValueConversions::of).collect(Collectors.toList())));
+        put("entity_tags", (e, a) -> ListValue.wrap(e.getServer().getTagManager().getEntityTypes().getTags().entrySet().stream().filter(entry -> entry.getValue().contains(e.getType())).map(entry -> ValueConversions.of(entry.getKey())).collect(Collectors.toList())));
         // deprecated
         put("has_tag", (e, a) -> new NumericValue(e.getScoreboardTags().contains(a.getString())));
 
@@ -1307,7 +1314,7 @@ public class EntityValue extends Value
             else if (v instanceof ListValue)
             {
                 List<Value> lv = ((ListValue) v).getItems();
-                if (lv.size() >= 1 && lv.size() <= 5)
+                if (lv.size() >= 1 && lv.size() <= 6)
                 {
                     String effectName = lv.get(0).getString();
                     StatusEffect effect = Registry.STATUS_EFFECT.get(new Identifier(effectName));
@@ -1376,6 +1383,19 @@ public class EntityValue extends Value
             }
         });
 
+        put("swing", (e, v) -> {
+            if (e instanceof LivingEntity)
+            {
+                Hand hand = Hand.MAIN_HAND;
+                if (v != null)
+                {
+                    String handString = v.getString().toLowerCase(Locale.ROOT);
+                    if (handString.equals("offhand") || handString.equals("off_hand")) hand = Hand.OFF_HAND;
+                }
+                ((LivingEntity)e).swingHand(hand, true);
+            }
+        });
+
         put("silent",(e,v)-> e.setSilent(v.getBoolean()));
 
         put("gravity",(e,v)-> e.setNoGravity(!v.getBoolean()));

src/main/java/carpet/script/value/FunctionValue.java

@@ -215,7 +215,6 @@ public class FunctionValue extends Value implements Fluff.ILazyFunction
 
         }
         Value retVal;
-        boolean rethrow = false;
         try
         {
             retVal = body.evalValue(newFrame, type); // todo not sure if we need to propagete type / consider boolean context in defined functions - answer seems ye
@@ -228,15 +227,6 @@ public class FunctionValue extends Value implements Fluff.ILazyFunction
         {
             retVal = returnStatement.retval;
         }
-        catch (ThrowStatement throwStatement) // might not be really necessary
-        {
-            retVal = throwStatement.retval;
-            rethrow = true;
-        }
-        if (rethrow)
-        {
-            throw new ThrowStatement(retVal);
-        }
         Value otherRetVal = retVal;
         return (cc, tt) -> otherRetVal;
     }

src/main/java/carpet/script/value/ListValue.java

@@ -341,7 +341,7 @@ public class ListValue extends AbstractListValue implements ContainerValueInterf
         int from = normalizeIndex(fromDesc, size);
         if (toDesc == null)
             return new ListValue((Collection<? extends Value>) getItems().subList(from, size));
-        int to = normalizeIndex(toDesc, size);
+        int to = normalizeIndex(toDesc, size+1);
         if (from > to)
             return ListValue.of();
         return new ListValue((Collection<? extends Value>) getItems().subList(from, to));

src/main/java/carpet/script/value/MapValue.java

@@ -7,6 +7,7 @@ import net.minecraft.nbt.CompoundTag;
 import net.minecraft.nbt.Tag;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
@@ -16,7 +17,7 @@ import java.util.stream.Collectors;
 
 public class MapValue extends AbstractListValue implements ContainerValueInterface
 {
-    private Map<Value, Value> map;
+    private final Map<Value, Value> map;
 
     private MapValue()
     {
@@ -268,7 +269,9 @@ public class MapValue extends AbstractListValue implements ContainerValueInterfa
     public JsonElement toJson()
     {
         JsonObject jsonMap = new JsonObject();
-        map.forEach((k, v) -> jsonMap.add(k.getString(), v.toJson()));
+        List<Value> keys = new ArrayList<>(map.keySet());
+        Collections.sort(keys);
+        keys.forEach( k -> jsonMap.add(k.getString(), map.get(k).toJson()));
         return jsonMap;
     }
 }

src/main/java/carpet/script/value/NBTSerializableValue.java

@@ -4,6 +4,8 @@ import carpet.fakes.InventoryBearerInterface;
 import carpet.script.CarpetContext;
 import carpet.script.LazyValue;
 import carpet.script.exception.InternalExpressionException;
+import carpet.script.exception.ThrowStatement;
+import carpet.script.exception.Throwables;
 import carpet.script.utils.EquipmentInventory;
 import com.mojang.brigadier.StringReader;
 import com.mojang.brigadier.exceptions.CommandSyntaxException;
@@ -297,7 +299,7 @@ public class NBTSerializableValue extends Value implements ContainerValueInterfa
         }
         catch (CommandSyntaxException e)
         {
-            throw new InternalExpressionException("Incorrect item: "+itemString);
+            throw new ThrowStatement(itemString, Throwables.UNKNOWN_ITEM);
         }
     }
 

src/main/java/carpet/script/value/NullValue.java

@@ -9,6 +9,7 @@ import net.minecraft.nbt.Tag;
 
 public class NullValue extends NumericValue // TODO check nonsingleton code
 {
+    public static final NullValue NULL = new NullValue();
     @Override
     public String getString()
     {
@@ -32,7 +33,7 @@ public class NullValue extends NumericValue // TODO check nonsingleton code
     {
         return new NullValue();
     }
-    public NullValue() {super(0.0D);}
+    private NullValue() {super(false);}
 
     @Override
     public boolean equals(final Object o)

src/main/java/carpet/script/value/Value.java

@@ -15,12 +15,12 @@ import java.util.stream.Collectors;
 
 public abstract class Value implements Comparable<Value>, Cloneable
 {
-    public static NumericValue FALSE = new NumericValue(0);
-    public static NumericValue TRUE = new NumericValue(1);
-    public static NumericValue ZERO = FALSE;
-    public static NumericValue ONE = TRUE;
+    public static NumericValue FALSE = BooleanValue.FALSE;
+    public static NumericValue TRUE = BooleanValue.TRUE;
+    public static NumericValue ZERO = new NumericValue(0);
+    public static NumericValue ONE = new NumericValue(1);
 
-    public static NullValue NULL = new NullValue();
+    public static NullValue NULL = NullValue.NULL;
 
     public String boundVariable;
 
@@ -141,12 +141,12 @@ public abstract class Value implements Comparable<Value>, Cloneable
 
     public void assertAssignable()
     {
-        if (boundVariable == null || boundVariable.startsWith("_"))
+        if (boundVariable == null)// || boundVariable.startsWith("_"))
         {
-            if (boundVariable != null)
+            /*if (boundVariable != null)
             {
                 throw new InternalExpressionException(boundVariable+ " cannot be assigned a new value");
-            }
+            }*/
             throw new InternalExpressionException(getString()+ " is not a variable");
 
         }
@@ -186,7 +186,7 @@ public abstract class Value implements Comparable<Value>, Cloneable
         int size = value.length();
         int from = ListValue.normalizeIndex(fromDesc, size);
         if (toDesc == null) return new StringValue(value.substring(from));
-        int to = ListValue.normalizeIndex(toDesc, size);
+        int to = ListValue.normalizeIndex(toDesc, size+1);
         if (from > to) return StringValue.EMPTY;
         return new StringValue(value.substring(from, to));
     }

src/main/java/carpet/script/value/ValueConversions.java

@@ -2,6 +2,8 @@ package carpet.script.value;
 
 import carpet.fakes.BlockPredicateInterface;
 import carpet.script.exception.InternalExpressionException;
+import carpet.script.exception.ThrowStatement;
+import carpet.script.exception.Throwables;
 import carpet.utils.BlockInfo;
 import net.minecraft.block.BlockState;
 import net.minecraft.block.MaterialColor;
@@ -158,7 +160,7 @@ public class ValueConversions
                         }
                     }
                     if (dim == null)
-                        throw new InternalExpressionException("Incorrect dimension string: "+dimString);
+                        throw new ThrowStatement(dimString, Throwables.UNKNOWN_DIMENSION);
                     return server.getWorld(dim);
             }
         }