Re: Access "current duration" from music functions

[Lukas-Fabian Moser]

Hi David,
> > But it does not seem to be possible to _set_ this "current duration"
> > from scheme, does it?
> Why would that be a good idea?

Consider a situation where \myFunction with signature (ly:duration?) 
generates some complex music expression in which the given duration is used.

Currently, in

(*) { a2 \myFunction 4 c }

is equivalent to

{ a2 \myFunction 4 c2 }

but in some situations it might be more natural for the user to expect 
(*) to yield

{ a2 \myFunction 4 c4 }.


(More concretely, in our use case, \myFunction expected "a chord or a 
duration". This leads to a behaviour where

a2 \myFunction 4

does not change the "current duration", but

a2 \myFunction <a c>4

does.)

Lukas