Hi, On Sat, 15 Feb 2025 at 13:10, 45mg <45mg.wri...@gmail.com> wrote:
> Here's a more minimal example from the guile-user mailing list 5 years > ago, that doesn't touch any Guix code at all: > https://lists.gnu.org/archive/html/guile-user/2020-03/msg00030.html Thanks, interesting. The manual reads “(guile) Regexp Functions“: For example, changing a match and retaining the text before and after, (regexp-substitute #f (string-match "[0-9]+" "number 25 is good") 'pre "37" 'post) ⇒ "number 37 is good" And now let replace 25 by xx and bang! --8<---------------cut here---------------start------------->8--- scheme@(guix-user)> ,use(ice-9 regex) scheme@(guix-user)> (regexp-substitute #f (string-match "[0-9]+" "number 25 is good") 'pre "37" 'post) $1 = "number 37 is good" scheme@(guix-user)> (regexp-substitute #f (string-match "[0-9]+" "number xx is good") 'pre "37" 'post) ice-9/boot-9.scm:1685:16: In procedure raise-exception: In procedure vector-ref: Wrong type argument in position 1 (expecting vector): #f Entering a new prompt. Type `,bt' for a backtrace or `,q' to continue. scheme@(guix-user) [1]> --8<---------------cut here---------------end--------------->8--- Well, here I’m not sure the issue is about the Backtrace but most probably because ’regexp-substitute’ returns an unexpected exception, instead of something more meaningful – it seems common that the regular expression does not match any inside the string, no? Cheers, simon
