What I mean is that a font-name attribute can be in the form:
"Bitstream Vera Sans, sans-serif, Oblique Bold"
If you want to check that the font-name is accepted, you have to inspect the output of the list and then see if it can be a valid combination of font + style attributes
This is not what I was searching for. I would like to automatize this check, so to prevent LilyPond to compile the score (or raise a warning) if the font is not found, with a function like:
\checkFont "Bitstream Vera Sans, sans-serif, Oblique Bold"
(ly:font-config-get-font-file font-name) appears the only scheme function candidate for this, but unfortunately it defaults to some system font when the wanted font-name does not correspond to any file.
Best,
P