[Sbcl-devel] defmacro and destructuring-bind Improvements

[Jan M. <jmo...@te...>]

Hi,

a few days ago, I started looking into bug 327537 [1] under the (much
appreciated) guidance of pkhuong. With the implementation technique
suggested by pkhuong, a sketch for compile time checks/optimizations of
PROPER-LIST-OF-LENGTH-P as suggested in the bug report was relatively
straight forward.

However, integration into the DEFMACRO machinery, which I assumed would
be the easy part, turned out to be not so easy. In fact, I got so
frustrated with the current implementation that I gave up on improving
it and started a rewrite.

I know that this must start to sound like a very bad idea, but I haven't
spend too much time yet and could easily live with the effort being
wasted. However, I do in fact think that the current DEFMACRO machinery
may have enough weaknesses to warrant a rewrite. Before I put more
effort into that, I would like to get some feedback, though.

Since this turned out to be much bigger in scope than I expected, I put
down my thoughts in the attached "document" (just an org-mode file,
sorry for the unusual format). The current incomplete and prototypical
implementation can be found at [2].

If this is not too much to ask, could you provide me with your thoughts
regarding whether this endeavour makes sense and if so, comment on the
aspects outlined in the attached document?

Many thanks in advance and kind regards,
Jan

[1] https://bugs.launchpad.net/sbcl/+bug/327537
[2] https://github.com/scymtym/sbcl/tree/wip-smarter-destructuring-bind