Srfi-159/166 - monadic formatting for guile

[Linus Björnstam]

Hi there!

I just ported the reference implementation of SRFI-159/166 (166 being the 
successor of 159) from the reference implementation in chibi scheme. The srfi 
document is here: https://srfi.schemers.org/srfi-166/srfi-166.html

SRFI-166 is like (ice-9 format) on steroids, drenched in molasses. It can do a 
lot more than (ice-9 format), but about 3x slower. I haven't started trying to 
make it fast just yet, but there are some low hanging fruit (like speeding up 
simple cases). I will wait with optimization until the srfi is finalized (and 
also maybe hear with Alex what he has in mind before trying to half-ass it 
myself). 

Anyway, the repo is here: https://bitbucket.org/bjoli/guile-srfi-159 . I 
haven't ported the tests, but playing with it in guile and chibi scheme 
produces the same result. Tests are up, but I'm travelling without computer the 
next week, so there is no time.

-- 
  Linus Björnstam