Re: Catch direction operators

[MING TSANG]

I was following the caption subject in lily user list. I run the following (copy from the lists).  I got error, please see the log at the end of lily code.

Thanks,

Ming

%lily code starts %%%%%%%%%%%%%%%%%

\version "2.17.27"

colorizeDir =

#(define-music-function (parser location item)

(symbol-list-or-music?)

(define (grob-colorize-dir grob)

(let ((ev (event-cause grob)))

(case (ly:event-property ev 'direction)

((1) red)

((-1) blue)

(else '())))))

#{ \tweak color #grob-colorize-dir #item #})

\new Staff \with { \colorizeDir Slur } {

c''^(

d'')

c''(

d'')

\undo \colorizeDir Staff.Slur

c''_(

d'')

<c'' e''>-\once \colorizeDir ^(

<d'' f''>)

}

% lily code ends %%%%%%%%%%%%%%

log file messAGE:

Starting lilypond-windows.exe 2.17.27 [Untitled (2)]...

Processing `c:/users/tsang/appdata/local/temp/frescobaldi-ylykff/tmpad4njh/document.ly'

Parsing...

c:/users/tsang/appdata/local/temp/frescobaldi-ylykff/tmpad4njh/document.ly:12:5: error: GUILE signaled an error for the _expression_ beginning here

#

{ \tweak color #grob-colorize-dir #item #})

c:/users/tsang/appdata/local/temp/frescobaldi-ylykff/tmpad4njh/document.ly:12:21: error: GUILE signaled an error for the _expression_ beginning here

#{ \tweak color #

grob-colorize-dir #item #})

c:/users/tsang/appdata/local/temp/frescobaldi-ylykff/tmpad4njh/document.ly:12:40: error: GUILE signaled an error for the _expression_ beginning here

#{ \tweak color #grob-colorize-dir #

item #})

c:/users/tsang/appdata/local/temp/frescobaldi-ylykff/tmpad4njh/document.ly:12:39: error: wrong type for argument 3. Expecting symbol list or music, found #<unspecified>

#{ \tweak color #grob-colorize-dir

#item #})

c:/users/tsang/appdata/local/temp/frescobaldi-ylykff/tmpad4njh/document.ly:12:46: error: GUILE signaled an error for the _expression_ beginning here

#{ \tweak color #grob-colorize-dir #item #

})

c:/users/tsang/appdata/local/temp/frescobaldi-ylykff/tmpad4njh/document.ly:12:47: error: syntax error, unexpected EVENT_IDENTIFIER

#{ \tweak color #grob-colorize-dir #item #}

)

Unbound variable: {

Unbound variable: grob-colorize-dir

Unbound variable: item

Unbound variable: }

C:/Users/Tsang/Dropbox/LilyPond/usr/share/lilypond/current/scm/ly-syntax-constructors.scm:56:23: In procedure memoization in _expression_ (apply (ly:music-function-extract fun) parser ...):

C:/Users/Tsang/Dropbox/LilyPond/usr/share/lilypond/current/scm/ly-syntax-constructors.scm:56:23: Missing body _expression_ in ((define (grob-colorize-dir grob) (let ((ev (event-cause grob))) (case (ly:event-property ev (quote direction)) ((1) red) ((-1) blue) (else (quote ())))))).

Exited with return code 1.