function definition now borrows variables from the defined context, not used context - so much more useful.

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

@@ -710,6 +710,21 @@ public class Expression implements Cloneable
             throw new ExpressionException(expr, token, "Problems in allocating global function "+name);
         }
 
+        Map<String, LazyValue> contextValues = new HashMap<>();
+        for (String global : globals)
+        {
+            LazyValue  lv = context.getVariable(global);
+            if (lv == null)
+            {
+                Value zero = Value.ZERO.reboundedTo(global);
+                contextValues.put(global, (cc, tt) -> zero);
+            }
+            else
+            {
+                contextValues.put(global, lv);
+            }
+        }
+
         context.host.globalFunctions.put(name, new UserDefinedFunction(arguments, function_context, token)
         {
             @Override
@@ -724,19 +739,7 @@ public class Expression implements Cloneable
                 }
                 Context newFrame = c.recreate();
 
-                for (String global : globals)
+                contextValues.forEach(newFrame::setVariable);
-                {
-                    LazyValue  lv = c.getVariable(global);
-                    if (lv == null)
-                    {
-                        Value zero = Value.ZERO.reboundedTo(global);
-                        newFrame.setVariable(global, (cc, tt) -> zero);
-                    }
-                    else
-                    {
-                        newFrame.setVariable(global, lv);
-                    }
-                }
                 for (int i=0; i<arguments.size(); i++)
                 {
                     String arg = arguments.get(i);
@@ -774,14 +777,6 @@ public class Expression implements Cloneable
                 {
                     throw new ExpressionException(e, t, "Error while evaluating expression: "+exc.getMessage());
                 }
-                for (String global: globals)
-                {
-                    LazyValue lv = newFrame.getVariable(global);
-                    if (lv != null)
-                    {
-                        c.setVariable(global, lv);
-                    }
-                }
                 if (rethrow)
                 {
                     throw new ThrowStatement(retVal);