added parse_nbt and ability for set to submit params in list, and block data.

docs/scarpet/api/BlocksAndWorldAccess.md

@@ -36,11 +36,14 @@ print(b); // 'stone', block was evaluated 'eagerly' but call to `block`
 All the functions below can be used with block value, queried with coord triple, or 3-long list. All `pos` in the 
 functions referenced below refer to either method of passing block position.
 
-### `set(pos, block, property?, value?, ...)`
+### `set(pos, block, property?, value?, ..., block_data?)`, `set(pos, block, l(property?, value?, ...), block_data?)`
 
 First part of the `set` function is either a coord triple, list of three numbers, or other block with coordinates. 
 Second part, `block` is either block value as a result of `block()` function string value indicating the block name, 
-and optional `property - value` pairs for extra block properties. If `block` is specified only by name, then if a 
+and optional `property - value` pairs for extra block properties. Optional `block_data` include the block data to 
+be set for the target block.
+
+If `block` is specified only by name, then if a 
 destination block is the same the `set` operation is skipped, otherwise is executed, for other potential extra
 properties.
 
@@ -64,6 +67,7 @@ set(x,y,z,'iron_trapdoor[half=top]')  // Incorrect. sets bottom iron trapdoor -
 set(x,y,z,'iron_trapdoor','half','top') // correct - top trapdoor
 set(x,y,z, block('iron_trapdoor[half=top]')) // also correct, block() provides extra parsing
 set(x,y,z,'hopper[facing=north]{Items:[{Slot:1b,id:"minecraft:slime_ball",Count:16b}]}') // extra block data
+set(x,y,z,'hopper', l('facing', 'north'), nbt('{Items:[{Slot:1b,id:"minecraft:slime_ball",Count:16b}]}') ) // same
 </pre>
 
 ### `without_updates(expr)`

src/main/java/carpet/script/CarpetExpression.java

@@ -764,27 +764,55 @@ public class CarpetExpression
         {
             CarpetContext cc = (CarpetContext)c;
             ServerWorld world = cc.s.getWorld();
-            if (lv.size() < 2 || lv.size() % 2 == 1)
-                throw new InternalExpressionException("'set' should have at least 2 params and odd attributes");
             BlockArgument targetLocator = BlockArgument.findIn(cc, lv, 0);
             BlockArgument sourceLocator = BlockArgument.findIn(cc, lv, targetLocator.offset, true);
             BlockState sourceBlockState = sourceLocator.block.getBlockState();
             BlockState targetBlockState = world.getBlockState(targetLocator.block.getPos());
-            if (sourceLocator.offset < lv.size())
+            List<Value> args = new ArrayList<>();
+            for (int i = sourceLocator.offset, m = lv.size(); i < m; i++)
             {
+                args.add(lv.get(i).evalValue(c));
+            }
+            CompoundTag data = null;
+            if (!args.isEmpty())
+            {
+                if (args.get(0) instanceof ListValue)
+                {
+                    if (args.size() == 2)
+                    {
+                        Value dataValue = NBTSerializableValue.fromValue( args.get(1));
+                        if (dataValue instanceof NBTSerializableValue)
+                        {
+                            data = ((NBTSerializableValue) dataValue).getCompoundTag();
+                        }
+                    }
+                    args = ((ListValue) args.get(0)).getItems();
+                }
+                else
+                {
+                    if ((args.size() & 1) == 1)
+                    {
+                        Value dataValue = NBTSerializableValue.fromValue( args.get(args.size()-1));
+                        if (dataValue instanceof NBTSerializableValue)
+                        {
+                            data = ((NBTSerializableValue) dataValue).getCompoundTag();
+                        }
+                    }
+                }
                 StateManager<Block, BlockState> states = sourceBlockState.getBlock().getStateManager();
-                for (int i = sourceLocator.offset; i < lv.size(); i += 2)
+                for (int i = 0; i < args.size()-1; i += 2)
                 {
-                    String paramString = lv.get(i).evalValue(c).getString();
+                    String paramString = args.get(i).getString();
                     Property<?> property = states.getProperty(paramString);
                     if (property == null)
                         throw new InternalExpressionException("Property " + paramString + " doesn't apply to " + sourceLocator.block.getString());
-                    String paramValue = lv.get(i + 1).evalValue(c).getString();
+                    String paramValue = args.get(i + 1).getString();
                     sourceBlockState = setProperty(property, paramString, paramValue, sourceBlockState);
                 }
             }
 
-            CompoundTag data = sourceLocator.block.getData();
+            if (data == null) data = sourceLocator.block.getData();
+            CompoundTag finalData = data;
 
             if (sourceBlockState == targetBlockState && data == null)
                 return (c_, t_) -> Value.FALSE;
@@ -794,12 +822,12 @@ public class CarpetExpression
             {
                 Clearable.clear(world.getBlockEntity(targetPos));
                 world.setBlockState(targetPos, finalSourceBlockState, 2);
-                if (data != null)
+                if (finalData != null)
                 {
                     BlockEntity be = world.getBlockEntity(targetPos);
                     if (be != null)
                     {
-                        CompoundTag destTag = data.copy();
+                        CompoundTag destTag = finalData.copy();
                         destTag.putInt("x", targetPos.getX());
                         destTag.putInt("y", targetPos.getY());
                         destTag.putInt("z", targetPos.getZ());
@@ -908,7 +936,7 @@ public class CarpetExpression
             Tag outtag = tool.getTag();
             if (outtag == null)
                 return LazyValue.TRUE;
-            Value ret = new NBTSerializableValue(outtag);
+            Value ret = new NBTSerializableValue(() -> outtag);
             return (_c, _t) -> ret;
 
         });
@@ -1951,11 +1979,9 @@ public class CarpetExpression
                 Value nbt = lv.get(position.offset).evalValue(c);
                 NBTSerializableValue v = (nbt instanceof NBTSerializableValue) ? (NBTSerializableValue) nbt
                         : NBTSerializableValue.parseString(nbt.getString());
-                if (v != null)
-                {
                 hasTag = true;
                 tag = v.getCompoundTag();
-                }
+
             }
             tag.putString("id", entityId.toString());
             Vec3d vec3d = position.vec;
@@ -2898,12 +2924,7 @@ public class CarpetExpression
         });
 
         this.expr.addLazyFunction("nbt", 1, (c, t, lv) -> {
-            Value v = lv.get(0).evalValue(c);
+            Value ret = NBTSerializableValue.fromValue(lv.get(0).evalValue(c));
-            if (v instanceof NBTSerializableValue)
-                return (cc, tt) -> v;
-            Value ret = NBTSerializableValue.parseString(v.getString());
-            if (ret == null)
-                return LazyValue.NULL;
             return (cc, tt) -> ret;
         });
 
@@ -2914,6 +2935,20 @@ public class CarpetExpression
             return (cc, tt) -> ret;
         });
 
+        this.expr.addLazyFunction("parse_nbt", 1, (c, t, lv) -> {
+            Value v = lv.get(0).evalValue(c);
+            if (v instanceof NBTSerializableValue)
+            {
+                Value parsed = ((NBTSerializableValue) v).toValue();
+                return (cc, tt) -> parsed;
+            }
+            NBTSerializableValue ret = NBTSerializableValue.parseString(v.getString());
+            if (ret == null)
+                return LazyValue.NULL;
+            Value parsed = ret.toValue();
+            return (cc, tt) -> parsed;
+        });
+
         //"overridden" native call that prints to stderr
         this.expr.addLazyFunction("print", -1, (c, t, lv) ->
         {

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

@@ -109,7 +109,7 @@ public class NBTSerializableValue extends Value implements ContainerValueInterfa
         }
         catch (CommandSyntaxException e)
         {
-            return null;
+           throw new InternalExpressionException("Incorrect NBT tag: nbtString");
         }
         NBTSerializableValue value = new NBTSerializableValue(tag);
         value.nbtString = nbtString;
@@ -317,10 +317,7 @@ public class NBTSerializableValue extends Value implements ContainerValueInterfa
             return v;
         if (v instanceof NullValue)
             return Value.NULL;
-        Value ret = NBTSerializableValue.parseString(v.getString());
+        return NBTSerializableValue.parseString(v.getString());
-        if (ret == null)
-            return Value.NULL;
-        return ret;
     }