Sent from Mail for Windows
From: spacecadet
Sent: Wednesday, 24 July 2024 19:11
To: Taylan Kammer; guile-devel@gnu.org
Subject: Re: Lexically bound macro, with lexically bound transformer
> I think the guile-user list might be more appropriate.
Noted
> (let-syntax ((outer (lambda (x) #'(+ 1 2))))
> (let-syntax ((inner (lambda (x) (outer x))))
> (inner)))
That works, but I guess this isn't possible then
(lambda* (#:key outer)
(let-syntax ((inner outer))
(inner ...)))
Since that would require evaluating run-time code at compile-time
>Is there a way to write a macro that's expanded at run-time?
With (local-eval #'(insert expression to be done at run-time)
(the-environment)), yes.
Caveat (from manual):
>Note that the current implementation of (the-environment) only captures
>“normal” lexical bindings, and pattern variables bound by syntax-case. It does
>not currently capture local syntax transformers bound by let-syntax,
>letrec-syntax or non-top-level define-syntax forms. Any attempt to reference
>such captured syntactic keywords via local-eval or local-compile produces an
>error.
The question is: why would you do that?
Best regards,
Maxime Devos
