Guile - State of 2 / Release of 3

[Jahrme Risner]

Hello all,

I recently saw that Andy Wingo (the primary maintainer of Guile) gave a talk 
about the upcoming release of Guile 3 (projected for “Spring 2019”).

https://www.gnu.org/software/guile/news/
https://fosdem.org/2019/schedule/event/guile3fasterprograms/

Currently version 2.9.1 is serving as the beta release for version 3.

For me, this announcement has raised a couple of questions:

1. What is the state of Guile 2 support right now? I know that there is a 
configuration command that enables experimental support, but what are the 
current limitations preventing the adoption of Guile 2 as the default version 
of Guile?

2. I understand that part of the issue with Guile 2 was a slowdown in 
performance due to the way in which LilyPond uses Guile; if substantiated, 
would the alleged doubling in speed compared to 2.2 place Guile 3 as a better 
candidate for the version of Guile to replace 1.8?

More generally, if someone was interested in working on Guile support, where 
would be the best place to start? Also, is there anyone who has been heading 
the work on moving to a newer version of Guile?

Best wishes,
Jahrme