Re: for-each?

[Jean Abou Samra]

Le lundi 03 juillet 2023 à 22:08 +0200, David Kastrup a écrit :
> Ugh, that's a can of worms.  #xxx will only accept a context-dependent
> set of values and reject values not fitting the context.  But the
> context includes whether or not, for example, we are in lyrics mode.
> For that reason \new ... accepts only a rather limited set of
> expressions, mostly delimited expressions where the mode-switching
> happens at the delimiters.
> 
> So it's more the $... that is problematic, but $... always comes with a
> warning tag with possibly untimely mode switching because of how parser
> lookahead works.
> 
> So all in all, I'm queasy about touching anything here.  It's not like
> you cannot just use one level of { } to get a context where #... will be
> well-defined.


On a related note, \new XXX is the only syntactic context I know
where XXX = \xxx is accepted if xxx was defined with define-music-function,
but not if it was defined with define-scheme-function, even if
the function returns music.

I dunno whether that's expected, or improvable. At any rate, it is
the only case where I am aware of an advantage of define-music-function
over define-scheme-function.

(And yes, I should really look into the parser code myself, but
I don't have the time right now.)

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