Re: IDE

[David Kastrup]

Eli Zaretskii <address@hidden> writes:

>> From: David Kastrup <address@hidden>
>> Cc: address@hidden
>> Date: Sat, 10 Oct 2015 21:11:57 +0200
>> 
>> Eli Zaretskii <address@hidden> writes:
>> 
>> > I indeed think that we should have infrastructure to turn on a major
>> > mode in a region of a buffer.
>> >
>> > I'm not sure we should use text properties or overlays for that,
>> > though.  The region could be part of the command that turns on the
>> > mode with region limits stored in markers.
>> 
>> A typical LilyPond score file switches into Scheme thousands of times
>> (most of the time just for a single scalar Scheme constant where an
>> actual mode switch would not necessarily be required, but also for all
>> user-defined functions and any non-trivial non-music expression).
>
> Not sure what you are saying.  Is it that a region with two ends is
> not enough, and we need a list of regions?  If so, I'm okay with that,
> and I don't see any serious obstacles to implement that.

It's rather a host of regions determined by syntax.

This can look like:

compressMMRests =
#(define-music-function (music) (ly:music?)
  (_i "Remove the empty bars created by multi-measure rests,
leaving just the first bar containing the MM rest itself.")
   (music-map
    (lambda (m)
      (if (eq? 'MultiMeasureRestMusic (ly:music-property m 'name))
          #{ \once \set Score.skipBars = ##t #m #}
          #{ #m #} ))
    music))

The first # switches into Scheme mode until the end, but then every #{
escape backs into LilyPond mode, and every # inside until #} goes back
to Scheme in order to evaluate expressions #t, m, and m in Scheme again.

Basically, inside of LilyPond, # escapes into Scheme for a single sexp,
and inside of Scheme, #{ escapes into LilyPond until the matching #} is
encountered, of course with #sexp again escaping into Scheme.  Either
can easily form multi-line expressions (or not) but definitely wants to
change the mode of font-locking.

-- 
David Kastrup