|
|
|
|
|
|
by leifaffles
4598 days ago
|
|
|
Can you clarify what you mean about "real" macros vs AST macros? The only obvious extension to normal AST-style macros I can think of is fexprs, which re-run the macro procedure on every invocation (rather than once at read/build/macroexpansion/whatever time). |
|
|
Firstly, AST visitors in Python (or whatever) are clunky and lots of code to do what you say. Hell, I think that it's borderline unpythonic.
You have to consider lots of things, such as whether or not you can put an stmt where you're inserting code, and write a lot of, frankly ugly, Python code to do it.
Hy macros (and really Lisp macros) that are first-class members of the language are nice, because they're a lot more clean to write.
In addition, since Hy does some nasty stuff under the hood to generate clean Python AST, you can do stuff like:
(Ok, that's a lie, since it'll do "print True if True else False", but if that had a (do) around everything, it'd still work by mangling the expression - just too tired to write that example right now :) )Fundamentally, a Hy macro IS an AST macro, just on the parsed and tokenized Hy code (which turns into AST), rather then fiddling with Python AST (which isn't even a stable interface).
That answer the question? :)