Answer to BTW: But what about debugging and stepping through the grammar execution? I assume that in the case you are describing EVAL is performed on text gene

Answer to BTW: But what about debugging and stepping through the grammar execution? I assume that in the case you are describing EVAL is performed on text generated "in memory". If you want to debug your code snippets (grammar actions) or just the grammar flow itself you still can't escape the generated code, even if you can escape generating an actual file. Answer to BTW2: Could you describe such a use case? what would be the motivation for it?