Reinhold Kainhofer <reinh...@kainhofer.com> writes:
> Am Montag, 5. September 2011, 23:02:11 schrieb David Kastrup:
>> #{..#} _is_ a direct Scheme construct interpreted at _read_ time in the
>> Scheme reader. It is enabled in scm/parser-ly-from-scheme.scm with the
>> line (read-hash-extend #\{ read-lily-expression).
>>
>> Within Lilypond, there is no place where you can read Scheme source but
>> not a #{...#} construct except in the load order before
>> scm/parser-ly-from-scheme.scm.
>
> Actually, what I meant was that sometimes you are writing a scheme
> function, and you are constructing context mods in scheme. If you
> already have a list of context mod entries, how can you create the
> context mod?
>
>
> (let* ((mod-entries (map create-mod-from-something your-list)))
> #{
> \with {
> % What comes here to turn the scheme list mod-entries into
> % context mod???
> }
> #})
(let ((mod-entries (map create-mod-from-something your-list)))
(reduce-right (lambda (a b) #{ \with { $b $a } #}) #{\with{}#} your-list))
> Also, this creates a snippet in lilypon syntax from an existing scheme
> list, just to have it parsed and the exact list created again by the
> parser. So, that's not very efficient.
I actually did not realize that evaluating the expression ran the parser
at runtime (as opposed to meddling with $-replacements happening at
compile time).
--
David Kastrup
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