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py/parse: Refactor code to remove assert(0)'s. 

This helps to improve code coverage.  Note that most of the changes in
this patch are just de-denting the cases of the switch statements.
This commit is contained in:
Damien George 2017-01-17 17:00:55 +11:00
parent 5314219f18
commit 86e942309a
1 changed files with 47 additions and 60 deletions
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107
py/parse.c
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@ -295,8 +295,9 @@ void mp_parse_node_print(mp_parse_node_t pn, size_t indent) {
case MP_PARSE_NODE_ID: printf("id(%s)\n", qstr_str(arg)); break;
case MP_PARSE_NODE_STRING: printf("str(%s)\n", qstr_str(arg)); break;
case MP_PARSE_NODE_BYTES: printf("bytes(%s)\n", qstr_str(arg)); break;
case MP_PARSE_NODE_TOKEN: printf("tok(%u)\n", (uint)arg); break;
default: assert(0);
default:
assert(MP_PARSE_NODE_LEAF_KIND(pn) == MP_PARSE_NODE_TOKEN);
printf("tok(%u)\n", (uint)arg); break;
}
} else {
// node must be a mp_parse_node_struct_t
@ -870,38 +871,30 @@ mp_parse_tree_t mp_parse(mp_lexer_t *lex, mp_parse_input_kind_t input_kind) {
// progress through the rule
for (; i < n; ++i) {
switch (rule->arg[i] & RULE_ARG_KIND_MASK) {
case RULE_ARG_TOK: {
// need to match a token
mp_token_kind_t tok_kind = rule->arg[i] & RULE_ARG_ARG_MASK;
if (lex->tok_kind == tok_kind) {
// matched token
if (tok_kind == MP_TOKEN_NAME) {
push_result_token(&parser, rule);
}
mp_lexer_to_next(lex);
} else {
// failed to match token
if (i > 0) {
// already eaten tokens so can't backtrack
goto syntax_error;
} else {
// this rule failed, so backtrack
backtrack = true;
goto next_rule;
}
if ((rule->arg[i] & RULE_ARG_KIND_MASK) == RULE_ARG_TOK) {
// need to match a token
mp_token_kind_t tok_kind = rule->arg[i] & RULE_ARG_ARG_MASK;
if (lex->tok_kind == tok_kind) {
// matched token
if (tok_kind == MP_TOKEN_NAME) {
push_result_token(&parser, rule);
}
mp_lexer_to_next(lex);
} else {
// failed to match token
if (i > 0) {
// already eaten tokens so can't backtrack
goto syntax_error;
} else {
// this rule failed, so backtrack
backtrack = true;
goto next_rule;
}
break;
}
case RULE_ARG_RULE:
case RULE_ARG_OPT_RULE:
rule_and_no_other_choice:
push_rule(&parser, rule_src_line, rule, i + 1); // save this and-rule
push_rule_from_arg(&parser, rule->arg[i]); // push child of and-rule
goto next_rule;
default:
assert(0);
goto rule_and_no_other_choice; // to help flow control analysis
} else {
push_rule(&parser, rule_src_line, rule, i + 1); // save this and-rule
push_rule_from_arg(&parser, rule->arg[i]); // push child of and-rule
goto next_rule;
}
}
@ -973,7 +966,9 @@ mp_parse_tree_t mp_parse(mp_lexer_t *lex, mp_parse_input_kind_t input_kind) {
break;
}
case RULE_ACT_LIST: {
default: {
assert((rule->act & RULE_ACT_KIND_MASK) == RULE_ACT_LIST);
// n=2 is: item item*
// n=1 is: item (sep item)*
// n=3 is: item (sep item)* [sep]
@ -1011,32 +1006,27 @@ mp_parse_tree_t mp_parse(mp_lexer_t *lex, mp_parse_input_kind_t input_kind) {
} else {
for (;;) {
size_t arg = rule->arg[i & 1 & n];
switch (arg & RULE_ARG_KIND_MASK) {
case RULE_ARG_TOK:
if (lex->tok_kind == (arg & RULE_ARG_ARG_MASK)) {
if (i & 1 & n) {
// separators which are tokens are not pushed to result stack
} else {
push_result_token(&parser, rule);
}
mp_lexer_to_next(lex);
// got element of list, so continue parsing list
i += 1;
if ((arg & RULE_ARG_KIND_MASK) == RULE_ARG_TOK) {
if (lex->tok_kind == (arg & RULE_ARG_ARG_MASK)) {
if (i & 1 & n) {
// separators which are tokens are not pushed to result stack
} else {
// couldn't get element of list
i += 1;
backtrack = true;
goto list_backtrack;
push_result_token(&parser, rule);
}
break;
case RULE_ARG_RULE:
rule_list_no_other_choice:
push_rule(&parser, rule_src_line, rule, i + 1); // save this list-rule
push_rule_from_arg(&parser, arg); // push child of list-rule
goto next_rule;
default:
assert(0);
goto rule_list_no_other_choice; // to help flow control analysis
mp_lexer_to_next(lex);
// got element of list, so continue parsing list
i += 1;
} else {
// couldn't get element of list
i += 1;
backtrack = true;
goto list_backtrack;
}
} else {
assert((arg & RULE_ARG_KIND_MASK) == RULE_ARG_RULE);
push_rule(&parser, rule_src_line, rule, i + 1); // save this list-rule
push_rule_from_arg(&parser, arg); // push child of list-rule
goto next_rule;
}
}
}
@ -1062,9 +1052,6 @@ mp_parse_tree_t mp_parse(mp_lexer_t *lex, mp_parse_input_kind_t input_kind) {
}
break;
}
default:
assert(0);
}
}