Re: Include a file if it exists

[Urs Liska]

Hello Gilles,

thank you very much.
Your solutions do work, but I don't think I'll use them in my project.

But you have unintentionally pushed me in the right direction (with the 
"emptyfile.ly" thing).
What I'll do now is:

- create empty replacement files 01.ily through 90.ily in an arbitrary 
folder
- add this folder to LilyPond's include path
- simply use \include "19.ily"

When that file isn't present in the current folder Lily will simply use 
the replacement one :-)

Thanks again

Best
Urs

Am 08.09.2014 23:14, schrieb Gilles THIBAULT:
> > I found out that using
> > #(ly:parser-parse-string (ly:parser-clone parser) "\\include \"01.ily\"")
> > _does_ actually work, but not when the included file contains variable
> > definitions (e.g. "music = ...").
> > Still no ideas?
> Perhaps something like that :
>
>
> %%%%%%%%%%
>
> \version "2.18.2"
>
> file = #(let((myfile "test.ly"))
> (if (file-exists? myfile)
>         myfile
>         "emptyfile.ly"))
>
> \include #file
>
> %%%%%%%%%
>
> which seems to works, but you need to create an empty file "emptyfile.ly"
> somewhere in your PATH.
> Alternatively, this seems also to work :
>
> ...
> (if (file-exists? myfile)
>         myfile
>         ""))
>
> but you will get an advertisement for the \include ""