LilyPond as a service

[Urs Liska]

I know this has been discussed in various flavors over the years, but I
need to raise the issue once more. Please note that this actually
encloses two questions.

Would it be possible to make LilyPond work in a server mode where the
whole Guile environment is loaded only once and the running server would
be listening and accepting files to compile (or maybe piped .ly input or
even Scheme music expressions)?

I assume this could provide significant improvements in a number of use
cases.

How fundamentally would one have to turn LilyPond's architecture upside
down for this? Is this conceptually impossible, just difficult or simply
too big to have been tackled so far?

Is this a task that could *somehow* be estimated in developer
weeks/months if one would dream of a paid developer?


###

A second idea is not directly related but would rely on the first. If
LilyPond *could* run as a server, would there be a chance to keep the
parsed document (i.e. not the engraving) in memory?
This may seem nonsensical, but if I'm not mistaken this would open up
the possibility to recompile a document with changed edition-engraver
mods. As these could also comprise skipTypesetting commands this would
make it possible to recompile an arbitrary excerpt (e.g. the current
system) of a score while tweaking, without LilyPond having to parse the
whole score over and over again.

Same questions as above: conceptually possible at all, any estimate on
the size of such an endeavour?

Thanks
Urs