Am So., 7. Okt. 2018 um 18:00 Uhr schrieb David Kastrup <[email protected]>:
>
> Thomas Morley <[email protected]> writes:
>
> > If you have too much time, you may have a look at ‘scheme-engraver.ly’
> > from
> > http://lilypond.org/doc/v2.13/input/regression/collated-files.html The
> > newer file uses the great 'make-engraver'-macro (by David Kastrup).
> > Otoh, this macro hides an engraver _is_ a list (which is obvious, if
> > you look in the older file).
>
> An engraver is not a list, just like it isn't a string like
> "Note_engraver". That's just how you _specify_ an engraver. If it's a
> list, the Scheme_engraver type will be used for actually instantiating
> an engraver (which is bound to a particular context), initialized using
> the list contents.
Hi David,
I don't understand the subtleties.
Could you elaborate a bit using the examples below.
testI =
#(list
(cons 'initialize
(lambda (trans)
(write trans))))
testII =
#(lambda (ctx) testI)
\layout {
\context {
\Voice
\consists #testI
\consists #testII
}
}
{ R1 }
testI is a list, testII a procedure using testI.
Both return #<Translator Scheme_engraver >, though.
Thanks,
Harm
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