Anybody invested in ly:make-simple-closure?

[David Kastrup]

ly:make-simple-closure is a powerful tool that can be used for doing a
lot of things in connection with callbacks.  It is also utterly
inscrutable and seriously underdocumented and it does not help that
nobody ever bothered defining a macro preprocessing its input which
would have obviated the need for extensive quasiquotes making for yet
more inscrutability.

It's likely that there are still LSR snippets using it even though our
current LilyPond code base only uses it in some very limited places
internally (and in some outdated manuals).  I am planning on throwing it
out altogether, preferably without replacement in the near future.  I
think that pretty much all the stuff it has been used for can be dealt
with using ordinary callbacks and unpure-pure-containers.

While it could be used as the basis for something more user-friendly,
I want to reorganize the pure/unpure/grob property caching mess and it
makes more sense to think about reintroducing more convenient callback
assembly mechanisms after I've done that.  So I think at the current
point of time we are better off throwing it out altogether while this
can be done at reasonable cost rather than trying to drag it through the
reorganization.

-- 
David Kastrup