Function builtin_python_import_rule

src/engine/builtins.cpp:1929–1999

#ifdef HAVE_PYTHON

LIST * builtin_python_import_rule( FRAME * frame, int flags )
{
    static int first_time = 1;
    char const * python_module   = object_str( list_front( lol_get( frame->args,
        0 ) ) );
    char const * python_function = object_str( list_front( lol_get( frame->args,
        1 ) ) );
    OBJECT     * jam_module      = list_front( lol_get( frame->args, 2 ) );
    OBJECT     * jam_rule        = list_front( lol_get( frame->args, 3 ) );

    PyObject * pName;
    PyObject * pModule;
    PyObject * pDict;
    PyObject * pFunc;

    if ( first_time )
    {
        /* At the first invocation, we add the value of the global
         * EXTRA_PYTHONPATH to the sys.path Python variable.
         */
        LIST * extra = 0;
        module_t * outer_module = frame->module;
        LISTITER iter, end;

        first_time = 0;

        extra = var_get( root_module(), constant_extra_pythonpath );

        iter = list_begin( extra ), end = list_end( extra );
        for ( ; iter != end; iter = list_next( iter ) )
        {
            string buf[ 1 ];
            string_new( buf );
            string_append( buf, "import sys\nsys.path.append(\"" );
            string_append( buf, object_str( list_item( iter ) ) );
            string_append( buf, "\")\n" );
            PyRun_SimpleString( buf->value );
            string_free( buf );
        }
    }

    pName   = PyString_FromString( python_module );
    pModule = PyImport_Import( pName );
    Py_DECREF( pName );

    if ( pModule != NULL )
    {
        pDict = PyModule_GetDict( pModule );
        pFunc = PyDict_GetItemString( pDict, python_function );

        if ( pFunc && PyCallable_Check( pFunc ) )
        {
            module_t * m = bindmodule( jam_module );
            new_rule_body( m, jam_rule, function_python( pFunc, 0 ), 0 );
        }
        else
        {
            if ( PyErr_Occurred() )