Re: function for Glissando with length stopped working

[David Kastrup]

Nick Payne <address@hidden> writes:

> On 25/07/13 21:32, David Kastrup wrote:
>> MarcM <address@hidden> writes:
>>
>>> I'm using nabble to post to lilypond and i had added the lilypond code. Are
>>> you not seeing it?
>>> http://lilypond.1069038.n5.nabble.com/function-for-Glissando-with-length-stopped-working-tp148399p148402.html
>>
>> "Nabble" is not the list server.  The official archive is at
>> <URL:http://lists.gnu.org/archive/html/lilypond-user/2013-07/msg00471.html>
>> and you'll see that your code did not actually make it to the list.
>>
>> Either Nabble itself or the official list server has scraped that
>> attachment off.  It would appear that only those who are reading the
>> list via Nabble will be able to see it.
>>
> Problem with convert-ly. When running convert-ly against that code to
> convert from 2.14.0 to 2.17.22, the function definition
>
> glissSize = #(define-music-function (blah...
>
> gets converted to
>
> glissSize = $(define-music-function (blah...
>
> The # is getting changed to a $...

Well yes, that's fishy.  It should instead have changed the #(begin to
$(begin in order to reflect the previous use of ly:export.  ly:export is
a rather tough cookie to convert by mere pattern matching.  Properly
parsing inner #{ ... #} environments would add another sizeable layer of
complexity.

But it's not like it's hard to correct this change.  What's less nice is
that issue 2240 is also involved.  With some new features, I'd rewrite
this completely as

\version "2.17.20"
glissSize =
#(define-event-function (parser location length)
  (number?)
  #{
  \tweak #'minimum-length #length \glissando
  #}
)

\score {
   {
    a'' \glissando e'' 
    a'' \glissSize #25 e'' 
  }
  \header {piece = "The default glissando is too short. usage: is a \glissSize 
#5 e "}
}

which is quite nicer but apparently has the downside that minimum-length
is getting completely ignored.  On the plus side, the default length
looks reasonable, but that's a weak consolation.

-- 
David Kastrup