Added scope package

src/build/core/ExecuteLeaf.go

@@ -13,7 +13,7 @@ func (f *Function) ExecuteLeaf(operation token.Token, register cpu.Register, ope
 	switch operand.Kind {
 	case token.Identifier:
 		name := operand.Text()
-		variable := f.Variable(name)
+		variable := f.VariableByName(name)
 
 		if variable == nil {
 			return errors.New(&errors.UnknownIdentifier{Name: name}, f.File, operand.Position)