Jan-Peter Voigt <jp.vo...@gmx.de> writes:
> Dear all,
>
> I stumbled over something that looks like a bug.
> If one uses ly:run-translator to process some music a dotted rest
> crashes lilypond:
>
> \version "2.19.82"
> #(ly:run-translator #{ r2. #} #{ \layout {} #})
>
> The error message is:
> Wrong number of arguments to #<procedure lookup-font (node alist-chain)>
>
> Does anybody know a way to circumvent this?
Well, looking up the definition of ly:run-translator I read:
LY_DEFINE (ly_run_translator, "ly:run-translator",
2, 1, 0, (SCM mus, SCM output_def),
"Process @var{mus} according to @var{output-def}. An"
" interpretation context is set up, and @var{mus} is"
" interpreted with it. The context is returned in its"
" final state.\n"
"\n"
"Optionally, this routine takes an object-key to"
" to uniquely identify the score block containing it.")
[...]
Which makes me barf. The final paragraph is just gobbledygook. It
doesn't help that this mysterious optional object-key is _accepted_ but
the function signature does not even contain a parameter declaration for
it.
Ok, onward. Running with -dverbose I get
-*- mode: compilation; default-directory: "/tmp/" -*-
Compilation started at Mon Sep 17 15:45:07
lilypond -dverbose gok.ly
GNU LilyPond 2.21.0
]
]
]
]
]
[... we should probably do something about those, dozens more]
Processing `gok.ly'
Parsing...
Interpreting music...Backtrace:
In unknown file:
?: 0* [lilypond-main ("gok.ly")]
In /usr/local/share/lilypond/2.21.0/scm/lily.scm:
1032: 1* (let* ((failed #)) (if (ly:get-option #) (begin #)) ...)
1032: 2* [lilypond-all ("gok.ly")]
1045: 3 (let* ((failed #) (separate-logs #) (ping-log #) ...) (gc) ...)
1057: 4* [for-each #<procedure #f (x)> ("gok.ly")]
In unknown file:
?: 5* [#<procedure #f (x)> "gok.ly"]
In /usr/local/share/lilypond/2.21.0/scm/lily.scm:
1059: 6* (let* (# # #) (if separate-logs #) (if ping-log #) ...)
1070: 7* [lilypond-file #<procedure #f (key failed-file)> "gok.ly"]
1105: 8 [catch ly-file-failed #<procedure #f ()> #<procedure #f (x . args)>]
In unknown file:
?: 9* [#<procedure #f ()>]
In /usr/local/share/lilypond/2.21.0/scm/lily.scm:
1106: 10* [ly:parse-file "gok.ly"]
In gok.ly:
Now it's getting interesting:
2: 11* [ly:run-translator # #]
In unknown file:
?: 12* [# #]
?: 13* [# # #]
?: 14* [#<Callback2_wrapper> #<Translator Dot_column_engraver > #<Grob Rest
> ...]
?: 15* [ly:rest::width #<Grob Rest >]
?: 16* [lookup-font #<undefined> ((# # # #) (# # # # ...) ())]
ERROR: In procedure lookup-font:
ERROR: Wrong number of arguments to #<procedure lookup-font (node alist-chain)>
Compilation exited abnormally with code 1 at Mon Sep 17 15:45:08
Ok, so we have
SCM
Rest::width (SCM smob)
{
return generic_extent_callback (unsmob<Grob> (smob), X_AXIS);
}
and
Rest::generic_extent_callback (Grob *me, Axis a)
{
/*
Don't want ledgers: ledgers depend on Y position, which depends on
rest collision, which depends on stem size which depends on beam
slop of opposite note column.
consequence: we get too small extents and potential collisions
with ledgered rests.
*/
SCM m = brew_internal_stencil (me, a != X_AXIS);
return ly_interval2scm (unsmob<Stencil> (m)->extent (a));
}
and
Rest::brew_internal_stencil (Grob *me, bool ledgered)
{
SCM durlog_scm = me->get_property ("duration-log");
if (!scm_is_number (durlog_scm))
return Stencil ().smobbed_copy ();
int durlog = scm_to_int (durlog_scm);
string style = robust_symbol2string (me->get_property ("style"), "default");
Font_metric *fm = Font_interface::get_default_font (me);
string font_char = glyph_name (me, durlog, style, ledgered, 0.0);
Stencil out = fm->find_by_name (font_char);
if (out.is_empty ())
me->warning (_f ("rest `%s' not found", font_char.c_str ()));
return out.smobbed_copy ();
}
Actually, looking at the traceback it would seem like lookup-font is not
actually called with the wrong number of arguments but something is
confused by the first argument being *undefined*. Which is a value that
usually is used in the C API for signifying "there isn't a proper Scheme
value here", so passing it around can lead to surprises.
This appears to be the problem from
Font_metric *
Font_interface::get_default_font (Grob *me)
{
Font_metric *fm = unsmob<Font_metric> (me->get_property ("font"));
if (!fm)
{
SCM chain = music_font_alist_chain (me);
fm = select_font (me->layout (), chain);
me->set_property ("font", fm->self_scm ());
}
return fm;
}
And likely because of me->layout () being unsuitable. Or not.
The problem only occurs with dotted rests. Maybe the dots rely on work
being done already by the rest itself but get typeset first?
I don't really know. This is sort of as deep as I get right now.
--
David Kastrup
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