so how would I wrote a macro that reverses an expression using sysntax rules only in #guile ?
@AbbieNormal
Can you provide an example of what you are looking for?
I'm considering of porting to guile this paragraph (Transform!)
https://www.greghendershott.com/fear-of-macros/Transform_.html
ans when I reach 3.3 I can't reproduce the reversion of an expression
@AbbieNormal
Maybe I can try something tonight.
(If only I had Guile on my Android phone...)
@AbbieNormal
The eval call smells bad to me haha
(define-syntax reverse-me
(syntax-rules ()
((reverse-me args args* ...)
(eval (reverse (list args args* ... values)) (interaction-environment)))))
mmmh
this solutions does work, I guess, but I'm afraid it's not idiomatic Guile or Scheme
Do you really need to involve environments and eval to reverse an expression ?
@AbbieNormal
Haha there are surely other ways. I don't really know what idiomatic means.
I just hacked in the REPL for 10 minutes. Trying to get the same output as the exercise example 👍
in fact I think I got it 👀
I'm not sure this is what I wanted, as I'm a bit confused now
But this seems to do the job
(define-syntax-rule
(reverse-me stx)
(reverse (syntax stx))
the thing is I'm reading that Racket tutorial and parallely also the Guile manual
But the mismatches are more and wider than I thought
I've almost only done Racket, but I thought Racket and Guile are both basically R5RS with a dash of R6RS except Racket and Guile do packages differently, Racket has the hash-lang system and Racket has immutable cons cells by default. And then of course both add some libs and syntax on top of base Scheme.
there were some misunderstandings on my side
Now, I think I mapped most of the Racket tutorial on Guile things
Notably, the Racket tutorial doesn't treat syntax-rules because Racket hasn't them
It jumps durectly to syntax-case
And the define-syntax-rule in Racket is for syntax-case, in Guile is for syntax-rules, as far as I understand
Any use other than "syntax-rules inside a define-syntax" will be implementation-specific.
syntax-rules is from R5RS and define-syntax-rule is a shortcut for define-syntax + syntax-rules when there is only one rule.
ah, it's 2 different chapters in the official documentation, good to know
But I was referring to this tutorial
> It’s called syntax-case, and has a shorthand for simple situations called define-syntax-rule.
Oh, I see. The author forgot the intermediate step: syntax-rules is a shorthand of syntax-case for simple (the vast majority of) situations, and define-syntax-rule is for the simplest case of syntax-rules.
@jeko
I call i tlike this
(reverse-me ("mom!" "hi"))
it's a bit naive, admittedly 😐