Music functions and #

[Erik Sandberg]

Hi,

I'm a bit frustrated that one have to add a # before strings and numbers, when 
calling a music function. This makes it impossible to do implement commands 
such as \bar in Scheme, since the argument to \bar has no # before it. 
Problems:
a) It increases the size of parser.yy (\bar could otherwise be defined in 
ly/*)
b) It makes it impossible to tweak \bar without re-compiling lilypond
c) It can potentially make users confused: It might be hard to remember in 
which situations you're supposed to add a # before a parameter to a music 
command.

Are there any plans to do anything about this?

One way could be to force the usage of # before all constants, i.e. forbid 
string and DIGIT in commands, and use embedded_scm instead. This would be a 
very consistent solution, with a more clean grammar as a result, but OTOH 
users may get frustrated that we require them to write more characters.

Another way is to allow the usage of non-SCM expressions as parameters to 
music functions. I did some experiments on parser.yy, in particular I 
replaced all embedded_scm parameters with music_function_param, where 
music_function_param is defined as identifier_init but with Music, post_event 
and number_expression removed. 
No shift/reduce conflicts were introduced, and it made it possible to write a 
clone of \bar as a Scheme function. In addition, it made it possibile to 
reduce the number of MUSIC_FUNCTION* tokens to 5.

Why is this not done? May I write a patch?

Erik