Re: New Issue: Disallow uncontained context-spec-music on top level

[Simon Albrecht]

On 23.09.2015 16:52, David Kastrup wrote:
> Simon Albrecht <address@hidden> writes:
>
> > <https://sourceforge.net/p/testlilyissues/issues/4617/>
> >
> > If
> >
> > $ git grep'= #(context-spec-music'
> > Documentation/snippets/additional-voices-to-avoid-collisions.ly:voiceFive=  #(co
> > ly/declarations-init.ly:melisma=  #(context-spec-music (make-property-set 'melis
> > ly/declarations-init.ly:melismaEnd=  #(context-spec-music (make-property-unset '
> > ly/property-init.ly:voiceOne=  #(context-spec-music (make-voice-props-set 0)
> > ly/property-init.ly:voiceTwo=  #(context-spec-music (make-voice-props-set 1)
> > ly/property-init.ly:voiceThree=  #(context-spec-music (make-voice-props-set 2)
> > ly/property-init.ly:voiceFour=  #(context-spec-music (make-voice-props-set 3)
> > ly/property-init.ly:oneVoice=  #(context-spec-music (make-voice-props-revert)
> >   
> >
> > doesn’t deceive me, there are seven commands which output
> > context-spec-music.
> >
> > It’s currently possible to use these on top level:
> >
> > %%%%% \version  "2.19.27"
> > \melisma
> > %%%%%
> It's possible to use any music variable at top level.
>
> > gives no warning or other message, but the attached (nonsense) output.
> >
> > This becomes a problem when ")" has been redefined and somewhere else
> > a Scheme expression has mismatched braces:
> >
> > %%%%% \version  "2.19.27"
> > ")" =\melismaEnd
> > #(define test "foo"))
> > %%%%%
> >
> > An extremely annoying case to debug, I can tell you.
> >
> > So redefining ")" should not preclude the warnings which turn up
> > without the redefinition.
> What warnings?  You are talking about an error here:
>
> /tmp/riga.ly:1:1: error: syntax error, unexpected EVENT_IDENTIFIER

That’s what I mean. Such a message immediately points to the culprit, 
which in my real-life case was an unmatched brace, a common source for 
problems. Without the message, I had to debug hundreds of lines of code 
within nested include files and without any kind of indication what to 
look for.

> and that error is based exclusively on the _content_ of ")" and not
> related to any independently produced warnings.  For example, you can
> write \] and just get
> /tmp/riga.ly:1:1: warning: cannot find start of ligature
>
> Making an error based on context-spec-music would be quite strange, by
> the way, since _many_ toplevel expressions are context-spec-music, like
> \new PianoStaff ...

Of course. The title I gave is nonsense then, I see.
I had been afraid there would be complications, but it would be very 
good if there were a way to give some kind of message pointing to the 
stray brace.

Yours, Simon