On 12 March 2018 at 09:25, David Kastrup <d...@gnu.org> wrote: > Gianmaria Lari <gianmarial...@gmail.com> writes: > > > On 11 March 2018 at 10:58, David Kastrup <d...@gnu.org> wrote: > > > >> Then Scheme expressions written using # in the middle of music are > >> expected to be music expressions. > > > >> If you want to insert an actual > >> duration, you need to write it preceded with $ so that it can have > >> different type (and trigger different syntactic rules). > >> > >> But $8 is not a duration. $(ly:make-duration 3 0) would be a duration. > > > > > > How does it work ? > > Originary I thought that before source compilation, there was a step > where > > to replace scheme expressions with their evaluation, like a preprocessor; > > that's why I tried c#(+ 6 2). But ok, it's clear it doesn't work in this > > way. > > > > Is this handled by the lilypond parser that create a parse tree and then > > according position in the tree and # or $ it expects different types? > > > > Thank you, g. > > From the "Extending LilyPond" guide: > > 1.2.1 LilyPond Scheme syntax > ---------------------------- > > The Guile interpreter is part of LilyPond, which means that Scheme can > be included in LilyPond input files. There are several methods for > including Scheme in LilyPond. > > The simplest way is to use a hash mark ‘#’ before a Scheme > expression. > > Now LilyPond’s input is structured into tokens and expressions, much > like human language is structured into words and sentences. LilyPond > has a lexer that recognizes tokens (literal numbers, strings, Scheme > [....]
Ok David, I think it's clear. Thanks a lot for the very detailed explanation, I appreciated your help. g.
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