[cffi-devel] A somewhat trollish idea

[Attila Lendvai]

Hi!

Recently i've made a project to use graphviz from lisp code through cffi
(cl-graphviz at http://common-lisp.net). In the process i used the cffi
generator of SWIG. It was not perfect so i've taken a look at the source
which is in c++. Then i gave up early... :)

And the idea: the CFFI/SWIG integration could be done in a different
philosophy, where SWIG were used only as a c++ parser and the CFFI generator
would be lisp code walking the C side parsed representation (using CFFI).

The idea is trollish, because i did not invest enough time to see the big
picture, but the generated file had serious trouble with statements like
#define FOO (1<<2)|(1<<3). The generator (written in C++) was trying to
interpret it with not so much luck. It would be simpler in lisp, and then
you could also generate the project specific lisp-side API right on.

The problem in general is not simple, because the value in a #define is a
plain string, and it's sci-fi to start a C++ parser on that sniplet and walk
the AST. In normal circumstances (c++ compiler) that define would go away in
the preprocessor stage, but in an FFI you want to use the named values from
lisp.

Enough trolling for now, and thanks for all the work on CFFI, it's great!

- attila

(alias 101 on irc &no 'its not lisp code :)
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