Re: bug-lilypond Digest, Vol 95, Issue 21

[Roman Stawski]

 On 08/10/2010 23:24, Carl Sorensen wrote:
>
> My version:
>
> \version "2.13.34"
>
> %% This scheme expression is evaluated during parsing; it creates a variable
> %% sequence-number with the value of 0
> #(define sequence-number 0)
>
> %% This is evaluated during parsing; it creates a markup function with one
> %% argument
> #(define-markup-command (score-sequence layout props sequence-number)
> (number?)
>  (interpret-markup layout props
>    (markup #:bold #:large (number->string sequence-number))))
>
> \new Staff {
>  %% This is evaluated during parsing; it adds 1 to the value of
>  %% sequence-number
>  #(set! sequence-number (1+ sequence-number))
>
>  %% This is evaluated during parsing; it puts a markup function on the
>  %% music tree, along with its argument, which is the current value
>  %% of sequence-number during the parsing stage.
>  \set Staff.instrumentName = \markup\score-sequence #sequence-number
>
>  %% This is evaluated during parsing.  It puts the markup function on
>  %% the music tree, along with the current value of sequence-number
>  a'1^\markup\score-sequence #sequence-number
> }
>
> \new Staff {
>  %% sequence-number is incremented during parsing
>  #(set! sequence-number (1+ sequence-number))
>
>  %% the current value of sequence-number is stored in the music tree as
>  %% an argument to the markup function (both calls)
>  \set Staff.instrumentName = \markup\score-sequence #sequence-number
>  b'1^\markup\score-sequence #sequence-number
> }
>
> \new Staff {
>  %% sequence number is incremented
>  #(set! sequence-number (1+ sequence-number))
>
>  %% The new value of sequence number is stored in the music tree.
>  \set Staff.instrumentName = \markup\score-sequence #sequence-number
>  c''1^\markup\score-sequence #sequence-number
> }
>  
> The general rule: if it's preceded by #, it's evaluated by the scheme
> interpreter during the parsing stage.  If it's not preceded by #, it will be
> evaluated during the translation stage.  (Although I won't promise this rule
> *always* holds).

Right, I understand now what you're saying. I find that it's a little
bit more messy that what I tried to do but it does have the great
advantage that *it works* (which is more than can be said for my effort!).
I appreciate the time you spent in annotating the two techniques.

Thanks again

Roman