diff --git a/py/parse.c b/py/parse.c index 698f796176..dc360e40ce 100644 --- a/py/parse.c +++ b/py/parse.c @@ -470,6 +470,63 @@ STATIC MP_DEFINE_CONST_MAP(mp_constants_map, mp_constants_table); STATIC void push_result_rule(parser_t *parser, size_t src_line, const rule_t *rule, size_t num_args); #if MICROPY_COMP_CONST_FOLDING +STATIC bool fold_logical_constants(parser_t *parser, const rule_t *rule, size_t *num_args) { + if (rule->rule_id == RULE_or_test + || rule->rule_id == RULE_and_test) { + // folding for binary logical ops: or and + size_t copy_to = *num_args; + for (size_t i = copy_to; i > 0;) { + mp_parse_node_t pn = peek_result(parser, --i); + parser->result_stack[parser->result_stack_top - copy_to] = pn; + if (i == 0) { + // always need to keep the last value + break; + } + if (rule->rule_id == RULE_or_test) { + if (mp_parse_node_is_const_true(pn)) { + // + break; + } else if (!mp_parse_node_is_const_false(pn)) { + copy_to -= 1; + } + } else { + // RULE_and_test + if (mp_parse_node_is_const_false(pn)) { + break; + } else if (!mp_parse_node_is_const_true(pn)) { + copy_to -= 1; + } + } + } + copy_to -= 1; // copy_to now contains number of args to pop + + // pop and discard all the short-circuited expressions + for (size_t i = 0; i < copy_to; ++i) { + pop_result(parser); + } + *num_args -= copy_to; + + // we did a complete folding if there's only 1 arg left + return *num_args == 1; + + } else if (rule->rule_id == RULE_not_test_2) { + // folding for unary logical op: not + mp_parse_node_t pn = peek_result(parser, 0); + if (mp_parse_node_is_const_false(pn)) { + pn = mp_parse_node_new_leaf(MP_PARSE_NODE_TOKEN, MP_TOKEN_KW_TRUE); + } else if (mp_parse_node_is_const_true(pn)) { + pn = mp_parse_node_new_leaf(MP_PARSE_NODE_TOKEN, MP_TOKEN_KW_FALSE); + } else { + return false; + } + pop_result(parser); + push_result_node(parser, pn); + return true; + } + + return false; +} + STATIC bool fold_constants(parser_t *parser, const rule_t *rule, size_t num_args) { // this code does folding of arbitrary integer expressions, eg 1 + 2 * 3 + 4 // it does not do partial folding, eg 1 + 2 + x -> 3 + x @@ -677,6 +734,10 @@ STATIC void push_result_rule(parser_t *parser, size_t src_line, const rule_t *ru } #if MICROPY_COMP_CONST_FOLDING + if (fold_logical_constants(parser, rule, &num_args)) { + // we folded this rule so return straight away + return; + } if (fold_constants(parser, rule, num_args)) { // we folded this rule so return straight away return;