Re: Regexp Functions

[Aaron Hill]

On 2020-06-08 12:47 pm, Caio Barros wrote:
> Hello!
>
> Em seg., 8 de jun. de 2020 às 08:37, Freeman Gilmore <
> freeman.gilmore@gmail.com> escreveu:
>
> > If the string is   "A ... B ... " , using Regexp Functions is it
> > possible, if 'A' matches [-] then 'B' would be replaced by "C"?    'A'
> > is first in the string.  Position of B is not constant.and may not be
> > there.
>
> Can you provide a little more context of what you are trying to do and 
> what
> this has to to with lilypond? What tools are you using to find and 
> replace
> strings using regex?

LilyPond -> Guile -> (use-modules (ice-9 regex))

Or I could be making the wrong assumption here.  ¯\_(ツ)_/¯

;;;;
(display
  (regexp-substitute/global #f
    (make-regexp "(^A.*)B" regexp/newline)
    (string-join '("A ... B ..." "D ... B ..."
                   "A ... E ..." "A ... B ...")
                 "\n" 'suffix)
    'pre 1 "C" 'post))
;;;;

====
A ... C ...
D ... B ...
A ... E ...
A ... C ...
====

The key here is to use a capturing group for the portion of the string 
before "B" that you need to preserve in the substitution.


-- Aaron Hill