Re: Fwd: Custom accidental styles

[David Kastrup]

Dan Eble <address@hidden> writes:

> [I dropped lilypond-devel when I replied.  Sending David’s reply to the list.]
>
> From: David Kastrup <address@hidden>
> Subject: Re: Custom accidental styles
> Date: May 21, 2016 at 12:29:05 EDT
> To: Dan Eble <address@hidden>
>
> Dan Eble <address@hidden> writes:
>
>>> On May 21, 2016, at 11:00 , David Kastrup <address@hidden> wrote:
>>> 
>>> Dan Eble <address@hidden> writes:
>>> 
>>>> On May 20, 2016, at 05:38 , Simon Albrecht <address@hidden> wrote:
>>>>> I was hoping to do further improvements to the code (comments and
>>>>> simplification) such as to make the threshold still lower, but I
>>>>> didn’t get there unfortunately.
>>>>> 
>>>>> HTH, Simon
>>>>> <accidental-style-baroque.ily>
>>>> 
>>>> Thank you.  That was helpful.  This worked for me:
>>>> 
>>>> %% Like voice, with additional cautionary cross-voice cancellations
>>>> #(set! accidental-styles (append accidental-styles
>>>>                      `((hymnbook-cautionary #f
>>>>                         (Voice ,(make-accidental-rule 'same-octave 0))
>>>>                         (Staff ,(make-accidental-rule 'same-octave 0))
>>>>                         Staff))))
>>> 
>>> accidental-styles.hymnbook-cautionary =
>>> #`(#f (Voice ,(make-accidental-rule 'same-octave 0))
>>>     (Staff ,(make-accidental-rule 'same-octave 0))
>>>     Staff)
>> 
>> It’s prettier, but it isn’t working.  With 2.19.42, I get "warning:
>> unknown accidental style” and the style is not put into effect.  The
>> attached file demonstrates both ways.
>
> Ugh.  Wouldn't work with define! instead of set! either I guess (which
> is what lily-lexer.cc uses effectively).  The variable is defined in a
> different module (lily rather than the current lexer).
>
> From the Guile docs:
>
>       `define' (when it occurs at top level), `scm_define' and
>    `scm_c_define' all create or set the value of a variable in the top
>    level environment of the current module.  If there was not already a
>    variable with the specified name belonging to the current module, but a
>    similarly named variable from another module was visible through having
>    been imported, the newly created variable in the current module will
>    shadow the imported variable, such that the imported variable is no
>    longer visible.
>
> So for
>
> xxx.yyy = ...
>
> we quite likely want set! semantics.  How about for
>
> xxx = ...
>
> ?

Ugh.

GNU LilyPond 2.19.43
Processing `input/regression/collision-2.ly'
Parsing.../usr/local/tmp/lilypond/out/share/lilypond/current/scm/lily-library.scm:583:32:
 In expression (break pred lst):
/usr/local/tmp/lilypond/out/share/lilypond/current/scm/lily-library.scm:583:32: 
Wrong type to apply: #<Prob: Music C++: Music((origin . #<location 
/usr/local/tmp/lilypond/out/share/lilypond/current/ly/declarations-init.ly:64:9>)
 (break-permission . force))((display-methods #<procedure #f (expr)>) (name . 
LineBreakEvent) (types line-break-event break-event event)) >

`break' is a procedure (automatically loaded) in (srfi srfi-1).  It is
also a music expression in ly/declarations-init.ly.

Overwriting it does not seem like a good idea...

-- 
David Kastrup