entity load handler and rework of handling of events.

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

@@ -21,9 +21,34 @@ public class FunctionArgument extends Argument
         this.function = function;
         this.args = args;
     }
-    public static FunctionArgument findIn(Context c, Module module, List<LazyValue> params, int offset, boolean prematureEvaluation, boolean allowNone)
+
+    /**
+     * @param c context
+     * @param module module
+     * @param params list of lazy params
+     * @param offset offset where to start looking for functional argument
+     * @param prematureEvaluation evaluates eagerly arguments in current context before returning
+     * @param allowNone none indicates no function present, otherwise it will croak
+     * @param checkArgs whether the caller expects trailing parameters to fully resolve function argument list
+     *                  if not - argument count check will not be performed and its up to the caller to verify
+     *                  if the number of supplied arguments is right
+     * @return argument data
+     */
+    public static FunctionArgument findIn(
+            Context c,
+            Module module,
+            List<LazyValue> params,
+            int offset,
+            boolean prematureEvaluation,
+            boolean allowNone,
+            boolean checkArgs)
     {
         Value functionValue = params.get(offset).evalValue(c);
+        if (functionValue.isNull())
+        {
+            if (allowNone) return new FunctionArgument(null, offset+1, null);
+            throw new InternalExpressionException("function argument cannot be null");
+        }
         if (!(functionValue instanceof FunctionValue))
         {
             String name = functionValue.getString();
@@ -31,11 +56,14 @@ public class FunctionArgument extends Argument
         }
         FunctionValue fun = (FunctionValue)functionValue;
         int argsize = fun.getArguments().size();
-        int extraargs = params.size() - argsize - offset - 1;
-        if (extraargs < 0)
-            throw new InternalExpressionException("Function "+fun.getPrettyString()+" requires at least "+fun.getArguments().size()+" arguments");
-        if (extraargs > 0 && fun.getVarArgs()==null)
-            throw new InternalExpressionException("Function "+fun.getPrettyString()+" requires "+fun.getArguments().size()+" arguments");
+        if (checkArgs)
+        {
+            int extraargs = params.size() - argsize - offset - 1;
+            if (extraargs < 0)
+                throw new InternalExpressionException("Function " + fun.getPrettyString() + " requires at least " + fun.getArguments().size() + " arguments");
+            if (extraargs > 0 && fun.getVarArgs() == null)
+                throw new InternalExpressionException("Function " + fun.getPrettyString() + " requires " + fun.getArguments().size() + " arguments");
+        }
         List<LazyValue> lvargs = new ArrayList<>();
         if (prematureEvaluation)
         {