Re: [Lilypond-auto] Issue 2858 in lilypond: Document \shape music function

[lilypond]

Comment #7 on issue 2858 by address@hidden: Document \shape music function
http://code.google.com/p/lilypond/issues/detail?id=2858

"The only misgiving I have is the way the grob name follows the  
sometimes-rather-long offset in the override form."
Complete agreement.  However, if the grob name becomes optional in front  
_and_ the music becomes optional at the end, one would need to write  
\default to actually skip the music argument.

I have for other reasons pondered how to do a mechanism where a skipped  
optional argument leads to a different remaining argument list and/or the  
previous arguments can be consulted for forming the rest of the argument  
list.

In general, it seems like the required complexity in implementing this sort  
of case-lambdaeque functionality, in applying it, and in understanding the  
resulting behaviors from a user view of the music functions are not really  
desirable.

As to "a separate command would be needed": after issue 2717 passes,  
\single\shape ... could be used,  However, you would still need to know the  
name of the grob.  It seems nicer to change the shape function instead.

Offtopic: it uses (define ((shape-curve offsets) item) ...  Is there a  
reason that this is not just (define (shape-curve item) ... and is later  
used as #shape-curve rather than #(shape-curve offsets) ?

Guilev2 does not support curried definitions by default (it requires  
loading an extra module), and in this case, the currying seems to serve no  
purpose.