Specialized propagators for specialized finite domains
======================================================

Concerns WP09 (concurrent constraint & logic programming workpackage).

We need specialized propagators for specialized finite domains (over
numbers, sets, intervals, etc.). There are two ways to provide them :

* rPython : which means implementing it entirely at intepreter level
  in a strict subset of Python,

* wrapping Gecode[1] : first finish the c-wrapper around Gecode
  (unless interfacing PyPy with C++ becomes available), then use
  rctypes to provide interpreter access to low-level Gecode
  functionality, and finally integrate it into the existing
  interpreter-level constraint solver.

Rctypes is what PyPy offers, using the python ctypes API, to interface
the interpreter with C code.

One reasonable target could be running the simple send-more-money
problem with very few actual search steps due to the efficient
propagation happening on integer finite domains.


[1] http://www.gecode.org/