Re: defineBarLine truncates bartype when span is #f

[Jean Abou Samra]

[Forgot the list, apologies!]

Le 14/01/2023 à 00:52, David Zelinsky a écrit :

In   { \defineBarLine bartype #'(end begin span) }
when `span' is `#f', only the first character of `bartype' is used.
Here is an example:

-----
\version "2.24.0"
{
   \defineBarLine ";|" #'(#t #t #f)
   a'1 \bar ";|" b'1 \bar
}
-----

This produces a single dotted barline, rather than a dotted-solid
combination as expected.

The explanation is in the definition of bar-line::compound-bar-line on
line 710 of bar-line.scm (the version in 2.24.0, though the current
version in git repository has the same feature).  In the initializations:

   (let* ...
          (span-glyph (get-span-glyph bar-glyph))
          (span-glyph-list (string->string-list span-glyph))

when span-glyph is #f, string->string-list returns '(""), a list of
length one.  Then further down, the for-each loops over the pair

        bar-glyph-list   span-glyph-list

and so does just one pass.


A reasonable fix seems to be to add these two lines to the definition of
get-span-glyph, right before the existing "if" statement (line 59 in
version 2.24.0):

     (if (and (boolean? span-glyph) (not span-glyph))
       (set! span-glyph ""))


[Maybe there's a better way to test if span-glyph is #f --- my knowledge
of scheme is pretty rudimentary!]

Then when span is #f, get-span-glyph will return a list of spaces of
length equal to the length of bar-glyph, which will do the right thing.


This doesn't have any effect on span-bar::compound-bar-line, which does
not use get-span-glyph, but calls

     (assoc-get bar-glyph span-bar-glyph-alist)

directly.

Thanks, added as https://gitlab.com/lilypond/lilypond/-/issues/6521
By the way, would you be willing to submit the fix yourself? Read

https://lilypond.org/doc/v2.25/Documentation/contributor/working-with-source-code

on how to proceed.

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