imports and better error reporting and stacktraces

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

@@ -1,9 +1,28 @@
 package carpet.script.exception;
 
-public class CarpetExpressionException extends ExpressionException
+import carpet.script.value.FunctionValue;
+import carpet.utils.Messenger;
+import net.minecraft.server.command.ServerCommandSource;
+
+import java.util.List;
+
+public class CarpetExpressionException extends RuntimeException
 {
-    public CarpetExpressionException(String message)
+    public List<FunctionValue> stack;
+
+    public CarpetExpressionException(String message, List<FunctionValue> stack)
     {
         super(message);
+        this.stack = stack;
+    }
+    public void printStack(ServerCommandSource source)
+    {
+        if (stack != null && !stack.isEmpty())
+        {
+            for (FunctionValue fun : stack)
+            {
+                Messenger.m(source, "e  ... in "+fun.fullName(), "e /"+(fun.getToken().lineno+1)+":"+(fun.getToken().linepos+1));
+            }
+        }
     }
 }