Re: booleans and conditional compilation?

[Simon Albrecht]

On 01.04.2016 21:23, Johannes Waldmann wrote:
> Hi.
>
> Is there a standard way of conditional compilation,
> e.g., to turn parts (on any level) of a score on and off?

The standard way is using tags, as Urs said.
But of course you can do everything you like via scheme:

\version "2.19.38"
foo = ##f
A = { c' }
B = { d' }
{
  #(if foo A B)
}

or, without music variables,

\version "2.19.38"
foo = ##f
{
  #(if foo
       #{ { c' } #}
       #{ { d' } #})
}



> However that seems like a work-around because lilypond
> has LISP inside and that sure has booleans and conditionals.
>
> Oh, and I looked up "conditional" in the docs
> (D. LilyPond command index) (no results).

There are no conditionals in LilyPond syntax, but you can use Guile 
Scheme. The use of it in LilyPond is explained in the Extending Manual 
<http://lilypond.org/doc/v2.19/Documentation/extending/index.html>.

HTH, Simon