Re: How to include a file just once?

[Tim McNamara]

On Jan 21, 2010, at 11:47 AM, Michael J. O'Donnell wrote:

> Is there a standard way to make sure that a file full of LilyPond  
> style
> definitions is included just once, no matter how many times it is  
> mentioned?
>
> I searched the Web site, mail archives, and /usr/shar/lilypond for
> "include once" and "include guard", to no avail. With the C
> preprocessor, there is a standard trick for setting and testing a
> variable to disable all but the first attempt to include a header  
> file.
> Some languages have an "include-once" command.
>
> I am putting together a large choral score from bookparts for each
> number in the work. I like to be able to produce either a single  
> number,
> or the whole score. The natural approach is to include style  
> definitions
> in each of the files that I might set, including the file to format  
> the
> whole score and the files to format individual numbers. Files to  
> format
> individual numbers also include the style definitions.
>
> I find that repeated inclusion of the same definitions leads  
> quickly to
> a segmentation fault.
>
> I can either add one more level of indirection, with one more file per
> number. Or, I can do some Scheme hacking, with a global variable to  
> set
> showing inclusion (tricky, because the variable needs to be testable
> reliably even when it has never been set explicitly).
>
> But, I'd prefer to use a well-known standard method, if it exists.

Without seeing your code, it's hard to tell what the problem is.   
When using \include to have a set of definitions, it is only  
necessary to do this once per .ly file.  I put them up high in the  
file (pop-chords.ly is a chord exceptions file to prettify the way  
Lilypond writes jazz chords; paren-2.ly is a definition to be able to  
parenthesize optional chord names):

\version "2.12.2"

#(ly:set-option 'delete-intermediate-files #t)

\paper {
    indent = 0.0
    ragged-last = ##f

}

\header {
  title = "Recycling Day"
  subtitle = "Concert Pitch"
  composer = "McNamara"
  meter = "Up-Tempo Swing or Bebop"
  copyright = "Tim McNamara, All Rights Reserved"
}

\include "../../pop-chords.ly"
\include "../../paren-2.ly"



*********************************
Any bookparts would only contain what is below this line, so the  
\include command would not be repeated:
*********************************

harmonies = \chordmode {

Chords go here

}

melody = \relative c' {
\override Staff.TimeSignature #'style = #'()
\time 4/4
\clef treble
\key c \major

Melody goes here

}

\score {
  <<

    \new ChordNames {
      \set chordChanges = ##t
      \harmonies
    }
    \new Staff \melody
  >>

}