swig/Examples/test-suite/aggregate.i

/* This file tests a few new contract features.
   First it checks to make sure the constant aggregation macro
   %aggregate_check() works.  This is defined in swig.swg.

   Next, it checks to make sure a simple contract works.
   To support contracts, you need to add a collection of
   macros to the runtime.  For python, they look like this:

#define SWIG_preassert(expr, msg)  if (!(expr)) { PyErr_SetString(PyExc_RuntimeError, (char *) msg #expr ); goto fail; } else
#define SWIG_postassert(expr, msg) if (!(expr)) { PyErr_SetString(PyExc_RuntimeError, (char *) msg #expr ); goto fail; } else

#define SWIG_inherit_preassert(expr, msg)  if (!(expr)) { PyErr_SetString(PyExc_RuntimeError, (char *) msg #expr ); goto fail; } else
#define SWIG_inherit_postassert(expr, msg) if (!(expr)) { PyErr_SetString(PyExc_RuntimeError, (char *) msg #expr ); goto fail; } else

#define SWIG_invariant(expr, msg)       if (!(expr)) { PyErr_SetString(PyExc_RuntimeError, (char *) msg #expr ); goto fail; } else
#define SWIG_invariant_begin(expr, msg) if (!(expr)) { PyErr_SetString(PyExc_RuntimeError, (char *) msg #expr ); goto fail; } else
#define SWIG_invariant_end(expr, msg)   if (!(expr)) { PyErr_SetString(PyExc_RuntimeError, (char *) msg #expr ); goto fail; } else

   Note: They are used like this:
   SWIG_preassert(x == 1, "Some kind of error message");

   Note: Contracts are still experimental.  The runtime interface may
   change in future versions.   Also, it's a bit nasty since these
   macros need to throw exceptions and get out of the wrapper.  Sorry.
   */

%module aggregate

%include "exception.i"
%aggregate_check(int, check_direction, UP, DOWN, LEFT, RIGHT)

%contract move(int x) {
require:
   check_direction(x);
}

%inline %{
#define UP    1
#define DOWN  2
#define LEFT  3
#define RIGHT 4

int move(int direction) {
    return direction;
}
%}