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guile bugs
- To: Jim Blandy <jimb AT red-bean dot com>
- Subject: guile bugs
- From: Greg Badros <gjb AT cs.washington dot edu>
- Date: 15 Sep 1999 22:39:34 -0700
- Cc: Jay Belanger <jay AT vh213601.truman dot edu>, scwm-discuss AT scwm.mit dot edu, guile AT sourceware.cygnus dot com
- References: <qrru2oyxtr7.fsf@elwha.cs.washington.edu> <199909141442.JAA17962@vh213601.truman.edu> <qrraeqpy0pl.fsf@elwha.cs.washington.edu> <199909141624.LAA19039@vh213601.truman.edu> <qrrlna9w5az.fsf@elwha.cs.washington.edu> <199909142309.SAA01374@vh213601.truman.edu> <qrrvh9bu8rp.fsf@elwha.cs.washington.edu> <m34sgvcttc.fsf@savonarola.red-bean.com>
Jim Blandy <jimb@red-bean.com> writes:
> > Any guile person want to remind me why SCM_BOOL_F was not made to be 0?
> > I know the tagging scheme is complex, but I'd certainly design it so
> > that I could have 0 be #f.
>
> So that pointers can be used directly, for speed. Probably not a good
> argument; if you subtract off the tag, that'll get added into whatever
> offset you're using to fetch a structure element...
Hmmm... yea, it sure would've saved a lot of bugs in Scwm (especially
early on) if Scheme booleans could be treated as C booleans. I
hypothesize that three changes would find a ton of bugs in Guile and Scwm:
1) SCM_BOOL_F should be 0 so it is false in C
2) SCM should not be a long, but instead be a pointer to undefined
struct as we discussed before. This would prevent misuse of an integer
as a Scheme value.
3) The checking of the argument numbers using a more sophisticated macro
like SCWM_PROC and Scwm's documentation extraction system (as mentioned
in an email earlier this week).
These are all pretty pervasive changes, unfortunately, but I'm guessing
they'd be a huge win in the long run.
Greg