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Re: \parenthesize and optional arguments
From: |
Marc Hohl |
Subject: |
Re: \parenthesize and optional arguments |
Date: |
Sat, 04 Jul 2015 09:56:13 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 |
Am 04.07.2015 um 09:17 schrieb David Kastrup:
[...]
You are thinking of LilyPond/Scheme as a procedural language here. What
happens here is that you calculate a suitable override and, well, throw
it away. The return value of this function, calculated later as "arg",
does not care what you have calculated here.
Ah, ok. Yes, I had the opinion that the override is something globally
inserted and executed before Lilypond places 'arg'.
Any pointers in the right direction are highly appreciated!
#UP (which is Lilypond-speak for +1).
Ok, it looks like this now:
\version "2.19.20"
parenthesize =
#(define-music-function (dir arg) ((number? 0) ly:music?)
(_i "Tag @var{arg} to be parenthesized. @arg{dir} is optional and may be
set to @code{#LEFT} or @code{#RIGHT} for left/right parentheses only.")
(if (memq 'event-chord (ly:music-property arg 'types))
;; arg is an EventChord -> set the parenthesize property
;; on all child notes and rests
(for-each
(lambda (ev)
(if (or (memq 'note-event (ly:music-property ev 'types))
(memq 'rest-event (ly:music-property ev 'types)))
(set! (ly:music-property ev 'parenthesize) #t)))
(ly:music-property arg 'elements))
;; No chord, simply set property for this expression:
(set! (ly:music-property arg 'parenthesize) #t))
(case dir
((-1) #{ \once\override ParenthesesItem.stencils =
#(lambda (grob)
(let ((par-list
(parentheses-item::calc-parenthesis-stencils grob)))
(list (car par-list) point-stencil ))) #arg #})
((1) #{ \once \override ParenthesesItem.stencils =
#(lambda (grob)
(let ((par-list
(parentheses-item::calc-parenthesis-stencils grob)))
(list point-stencil (cadr par-list)))) #arg #})
(else #{ #arg #})))
{ \parenthesize c \parenthesize #LEFT d \parenthesize #RIGHT e}
Would it make sense to enhance the parenthesize function like this, i.e.
create a patch for this?
Cheers,
Marc