relative include with ly:parser-parse-string

[Urs Liska]

Hi all,

I need to do a relative include with ly:parser-parse-string. But
regardless whether I use an \include string or retrieve the file through
ly:gulp-file LilyPond uses the search path to look up the target file.
The 'relative-includes option doesn't have any effect on this obviously.

So is there:

a) a way to perform a relative include from ly:parser-parse-string or

b) a way to determine the absolute path to the file where the current
code is read from (not the *location*)?

The current code in place is

(ly:parser-parse-string (ly:parser-clone) "\\include
\"internal/os-path.ily\"")

Thanks for any pointers
Urs