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Clean up handle_error function

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This commit is contained in:
Max Brunsfeld 2014-08-25 21:58:01 -07:00
parent 2318691e28
commit 826d4dfa23
1 changed files with 29 additions and 22 deletions
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51
src/runtime/parser.c
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@ -48,21 +48,22 @@ static size_t breakdown_stack(TSParser *parser, TSInputEdit *edit) {
return position;
}
static TSSymbol *expected_symbols(TSParser *parser, size_t *count) {
*count = 0;
static TSTree *build_error_node(TSParser *parser) {
size_t expected_symbol_count = 0;
const TSParseAction *actions =
actions_for_state(parser->language, ts_stack_top_state(&parser->stack));
for (size_t i = 0; i < parser->language->symbol_count; i++)
if (actions[i].type != TSParseActionTypeError)
(*count)++;
expected_symbol_count++;
size_t n = 0;
TSSymbol *result = malloc(*count * sizeof(*result));
TSSymbol *expected_symbols = malloc(expected_symbol_count * sizeof(TSSymbol *));
for (TSSymbol i = 0; i < parser->language->symbol_count; i++)
if (actions[i].type != TSParseActionTypeError)
result[n++] = i;
expected_symbols[n++] = i;
return result;
return ts_tree_make_error(ts_lexer_lookahead_char(&parser->lexer),
expected_symbol_count, expected_symbols, 0, 0);
}
static void shift(TSParser *parser, TSStateId parse_state) {
@ -115,19 +116,24 @@ static int reduce_extra(TSParser *parser, TSSymbol symbol) {
}
static int handle_error(TSParser *parser) {
size_t count = 0;
const TSSymbol *inputs = expected_symbols(parser, &count);
TSTree *error = ts_tree_make_error(ts_lexer_lookahead_char(&parser->lexer),
count, inputs, 0, 0);
TSTree *error = build_error_node(parser);
/*
* Run the lexer until it produces a token that allows for
* error recovery.
*/
for (;;) {
ts_tree_release(parser->lookahead);
size_t position = ts_lexer_position(&parser->lexer);
size_t prev_position = ts_lexer_position(&parser->lexer);
parser->lookahead =
parser->language->lex_fn(&parser->lexer, ts_lex_state_error);
/*
* If no characters are consumed, advance the lexer to the next
* character.
*/
int at_end = 0;
if (ts_lexer_position(&parser->lexer) == position)
if (ts_lexer_position(&parser->lexer) == prev_position)
at_end = !ts_lexer_advance(&parser->lexer);
if (at_end || parser->lookahead->symbol == ts_builtin_sym_end) {
@ -136,19 +142,20 @@ static int handle_error(TSParser *parser) {
}
/*
* Unwind the stack, looking for a state in which this token
* may appear after an error.
* Unwind the parse stack until a state is found in which an error is
* expected and the current lookahead token is expected afterwards.
*/
for (size_t j = 0; j < parser->stack.size; j++) {
size_t i = parser->stack.size - 1 - j;
TSStateId stack_state = parser->stack.entries[i].state;
TSParseAction action_on_error = actions_for_state(
parser->language, stack_state)[ts_builtin_sym_error];
for (size_t i = parser->stack.size - 1; i + 1 > 0; i--) {
TSStateId state = parser->stack.entries[i].state;
TSParseAction action_on_error =
actions_for_state(parser->language, state)[ts_builtin_sym_error];
if (action_on_error.type == TSParseActionTypeShift) {
TSStateId state_after_error = action_on_error.data.to_state;
if (actions_for_state(parser->language,
state_after_error)[parser->lookahead->symbol]
.type != TSParseActionTypeError) {
TSParseAction action_after_error = actions_for_state(
parser->language, state_after_error)[parser->lookahead->symbol];
if (action_after_error.type != TSParseActionTypeError) {
ts_stack_shrink(&parser->stack, i + 1);
ts_stack_push(&parser->stack, state_after_error, error);
return 1;