[Sbcl-devel] preview: MORE ALIENS for sb-grovel

[Andreas F. <as...@bo...>]

Hi all,

this is the longest-lasting project that I have done with SBCL yet (-:

So, what does it do?

SB-GROVEL currently uses vectors of bytes in lisp space for
structures. This approach has a few problems:

 * You have to use with-pinned-objects when you call functions that
   take a structure as arguments.
 * Alien function definitions and structure definitions can't make use
   of predefined alien types: you have to use (* t) or (unsigned 8)
   instead of more useful names.
 * You have to cast structures that were returned from functions into
   lisp space.

So, it would be a good idea to use SB-ALIEN structures for this kind
of thing. Of course, using SB-ALIEN has a disadvantage, too:

sb-grovel's vector design is ingenious in that it doesn't have to care
if the element you want is in a union or on the structure toplevel. it
sees an offset and a size. to make SB-GROVEL be as smart with SB-ALIEN
structs is a serious undertaking. (-:

Which I have attempted and, surprisingly, it seems to work with only a
few modifications to constants.lisp (lisp code using sb-grovel needs
to be reworked a bit more, though).

I have converted SB-POSIX to use the new scheme. SB-BSD-SOCKETS is
missing yet.

So, without further ado, here's the code. Be merry!