cython_callback_binding.pyx

constraint_handlers = {}

from cpython.ref cimport PyObject

cdef void _call_constraint_presolve_func(cpConstraint *constraint, cpSpace *space):
    global constraint_handlers
    global current_spaces
    py_space = current_spaces[0]
    python_constraint = constraint.data
    constraint_dict = constraint_handlers[python_constraint]
    constraint_dict['pre_solve'](constraint_dict['constraint'], py_space)

cdef class Constraint:
   def __init__(self, args):
        self._constraint = cpConstraint()
        cdef PyObject* ptr = <PyObject*>self
        self._constraint.data = <cpDataPointer>ptr
        global constraint_handlers
        constraint_handlers[self._constraint.data] = {'constraint': self}


   property pre_solve:
        def __set__(self, func):
            self._set_py_presolve_handler(func)
            self._constraint.preSolve = _call_constraint_presolve_func

   def _set_py_presolve_handler(self, presolve_func):
        global constraint_handlers
        constraint_handlers[self._constraint.data]['pre_solve'] = presolve_func