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Re: Extended bar checking?
From: |
Jean Abou Samra |
Subject: |
Re: Extended bar checking? |
Date: |
Sun, 18 Sep 2022 21:33:42 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.1 |
Le 18/09/2022 à 20:32, Mats Bengtsson a écrit :
Hi,
I've been pondering about a missing feature in LilyPond, namely the
possibility to get a warning printout if there isn't an explicit bar
check ("|") in the input file at the end of each measure. This would
catch many of the typos I personally do when entering music, where I
happen to forget to change a duration, or enter the wrong duration, so
that the current default duration happens to be, say, double the
correct duration.
Example: Let's say I want to type
\relative c' {
c4 d e2 |
g1 |
g4 f e d |
c1
}
but forget to add the duration "4" in the third measure:\relative c' {
c4 d e2 |
g1 |
g f e d |
c1
}
Obviously, this will not give any bar check warning, but if there was
a possibility to get a warning also for missing bar checks, I would
immediately catch those mistakes. This feature should not be on by
default, but for those of us who consequently add bar checks in the
input files, it would be extremely helpful.
In another email thread today, Valentine provided an implementation of
a Bar_check_warning_egraver is somewhat along the same lines, but that
unfortunatly fails to catch the typo in the above example since it
only detects notes where the duration crosses a bar line. As far as I
can see, the idea of Valentine's implementation cannot easily be
extended to do what I'm after and it's not immediately obvious to me
how hard it would be to implement it. Perhaps some of you clever
LilyPond hackers on the list have an idea, otherwise I will send it as
a feature request to the bug list.
Yes, it can be done.
\version "2.23.13"
#(define-event-class 'event 'StreamEvent) % cough
"|" = { | #(make-music 'Event 'is-bar-check #t) }
#(define (Require_bar_check_engraver context)
(let ((heard #f)
(previous-rhythmic-ev #f)
(now-rhythmic-ev #f))
(make-engraver
(listeners
((event engraver event)
(when (ly:event-property event 'is-bar-check #f)
(set! heard #t)))
((rhythmic-event engraver event)
(set! now-rhythmic-ev event)))
((stop-translation-timestep engraver)
(when (and (not heard)
(ly:context-property context 'measureStartNow #f))
(if previous-rhythmic-ev
(ly:event-warning previous-rhythmic-ev "missing bar check
after this note/rest")
;; maybe \skip <music>, for which it is hard to get a location
(ly:warning "missing bar check at end of measure ~a"
(1- (ly:context-property context
'currentBarNumber)))))
(set! heard #f)
(set! previous-rhythmic-ev now-rhythmic-ev)
(set! now-rhythmic-ev #f)))))
\layout {
\context {
\Voice
\consists #Require_bar_check_engraver
}
}
\relative c' {
c4 d e2 |
g1 |
g f e d | % notes wrongly entered
s1 % missing bar check
\skip {
c1 % missing bar check
c1
} |
}
However, be aware of the limitations. This only checks that
in each voice, there is a bar check at every measure end.
It does not check that every component of the music generating
this voice has this bar check. For example, this gets accepted
without warning:
\new Voice << { c'1 | d' | e' | } { e'1 f' g' } >>
To my knowledge, it's not possible to also warn about this one without
some serious modifications in LilyPond's internals.
Jean
Re: Extended bar checking?, Valentin Petzel, 2022/09/19