Hello Maxime!
On 7/28/22 02:55, Maxime Devos wrote:
These macros all sound more complicated than necessary -- on the first one,
I've sent you a message with sneek:
;; By: Maxime Devos
;; This does not recurse into #(...).
;; Also, such a construct does not nest well, you can't put a
replace-result-placeholder inside a replace-result-placeholder meaningfully,
;; so I'm wondering why you're doing this, maybe your goal can be accomplished
more robustly with a different method.
(eval-when (expand load eval)
(define (replace-placeholder new code) ; <--- recursively transforms code to
replace '<?>' by new
(syntax-case code (<?>)
(<?> new)
((x . y)
#`(#,(replace-placeholder new #'x) . #,(replace-placeholder new #'y)))
(rest #'rest))))
(define-syntax replace-result-placeholder
(lambda (s)
(syntax-case s (<?>) ; <?>: placeholder
((_ new code) (replace-placeholder #'new #'code)))))
(display (replace-result-placeholder
quote
(<?> bar))) ; -> bar
(I think thinking in terms of 'operations' and special-casing lambda etc would
make things harder here)
As a bonus, this supports things like `((x . <?>) (z . w)) which aren't
supported by the original macro as that macro assumed lists.
Greetings,
Maxime.
I'll need to look at this and learn about eval-when. I also did not think about
vectors yet. Thank you!
Best regards,
Zelphir
--
repositories:https://notabug.org/ZelphirKaltstahl
