Re: Regexp Functions

[Michael Gerdau]

Hi!

I find your description difficult to understand. Maybe you could provide an set of examples showing exactly what you wish to be modified into what.

Apart from that your problem sounds as if it is trivial when using non greedy regular expressions. As Aaron already wrote you need expressions to capture the whole block and isolate the subexpressions you wish to operate on (A, ... and x in your case - if I understand you correctly)

Kind regards,

Michael 

Mobil gesendet

Am 09.06.2020 um 07:00 schrieb Freeman Gilmore <freeman.gilmore@gmail.com>:



Caio and Arron:

 I am writing this at the top to start over and answer Caio's questions.    Say you have an accidental  string  name  "A..." and the stem is up; then the same accidental  with the stem down would be named  "-A...".      "A".. would be a short string like LilyPond  uses for accidentals.

If you want to use the accidental more than one time say 2 then  write the strings like this, "A...x2" and "-A...x2".   But the second name is wrong, the "x2" part needs to go with the stem.    "A...x2" is the logical entry but the "x" needs to be replaced with "-x".  Before I do this I need a space before the "x", i replace "x",, if it exists with " x"  if it exists.     I now have the 4 possibilities "A...",  "-A...", "A... x2", "-A... x2".    

My question is, is there a procedure  that sees the [-] then searches for "x" and replaces it with "-x".    

I could add the "-" to the "x" at entry but want to keep it simple, x (times ) 2 is logical (and saves a stroke).  The  next step would be to split the strings into two strings if a space exists.    So  "A... x2" becomes  "A..." " x2" and  "-A... x2" becomes "-A..." "-x2" ; two glyph each to form ligatures.   

Thank you, ƒg

On Mon, Jun 8, 2020 at 4:31 PM Aaron Hill <lilypond@hillvisions.com> wrote:

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