[Chicken-users] jbogenturfa'i compile time down to 12 minutes

[Alan Post]

Felix has been corresponding with me privately, providing
suggestions for how to modify the code generated by
genturfa'i to generate smaller or more efficient C code
when compiled by Chicken.

I've modified genturfa'i to produce top-level definitions
for all of the non-terminal rules in a grammar.  This was
suggested to my early on by Peter Bex on IRC, though to
Felix's enduring credit he proved to me why with code
examples.  :-)

After making this change, the jbogenturfahi egg compiles in
roughly 12 minutes, down from 2.5 hours.  The .c file generated 
is now around 25MB rather than 60MB.  The .so file is 1.7MB,
down from 9-10MB.  That still seems large to me, but gcc doesn't
complain!

I also used this opportunity to do a fair bit of optimization
to genturfa'i as I tried various approaches.  While it didn't
affect this particular issue, I did manage to substantially reduce
the runtime memory size of the parser generators produced by
genturfa'i, which may well avoid other problems for me in the
future.

This is a good enough result for me to continue developing these
eggs rather than focusing on this problem.  I will likely create
a separate .so file for the grammar itself so that I only run
this 12 minute compile when I modify the PEG grammar or the
genturfa'i egg, which will happen much less frequently than other
code changes I'll be making to jbogenturfa'i as I develop it.

I will be more than happy to thoroughly test any changes mode to
Chicken's compiler that attempt to optimize large letrec forms
with mutually recursive definitions, should any work be done in
that area.

Thank you everyone!  I was afraid this problem would not have a
satisfying resolution.  I'm really glad to be working with this
community!

-Alan
-- 
.i ko djuno fi le do sevzi