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tree-sitters/c/examples/parser.c

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#include "runtime/parser.h"
#include <assert.h>
#include <stdio.h>
#include <limits.h>
#include <stdbool.h>
#include "tree_sitter/runtime.h"
#include "runtime/tree.h"
#include "runtime/lexer.h"
#include "runtime/length.h"
#include "runtime/array.h"
#include "runtime/language.h"
#include "runtime/alloc.h"
#include "runtime/reduce_action.h"
#include "runtime/error_costs.h"
#define LOG(...) \
if (self->lexer.logger.log) { \
snprintf(self->lexer.debug_buffer, TS_DEBUG_BUFFER_SIZE, __VA_ARGS__); \
self->lexer.logger.log(self->lexer.logger.payload, TSLogTypeParse, \
self->lexer.debug_buffer); \
} \
if (self->print_debugging_graphs) { \
fprintf(stderr, "graph {\nlabel=\""); \
fprintf(stderr, __VA_ARGS__); \
fprintf(stderr, "\"\n}\n\n"); \
}
#define LOG_STACK() \
if (self->print_debugging_graphs) { \
ts_stack_print_dot_graph(self->stack, self->language->symbol_names, \
stderr); \
fputs("\n\n", stderr); \
}
#define LOG_TREE() \
if (self->print_debugging_graphs) { \
ts_tree_print_dot_graph(self->finished_tree, self->language, stderr); \
fputs("\n", stderr); \
}
#define SYM_NAME(symbol) ts_language_symbol_name(self->language, symbol)
typedef struct {
Parser *parser;
TSSymbol lookahead_symbol;
TreeArray *trees_above_error;
uint32_t tree_count_above_error;
bool found_repair;
ReduceAction best_repair;
TSStateId best_repair_next_state;
uint32_t best_repair_skip_count;
} ErrorRepairSession;
typedef struct {
Parser *parser;
TSSymbol lookahead_symbol;
} SkipPrecedingTreesSession;
static void parser__push(Parser *self, StackVersion version, Tree *tree,
TSStateId state) {
ts_stack_push(self->stack, version, tree, false, state);
ts_tree_release(tree);
}
static bool parser__breakdown_top_of_stack(Parser *self, StackVersion version) {
bool did_break_down = false;
bool pending = false;
do {
StackPopResult pop = ts_stack_pop_pending(self->stack, version);
if (!pop.slices.size)
break;
did_break_down = true;
pending = false;
for (uint32_t i = 0; i < pop.slices.size; i++) {
StackSlice slice = pop.slices.contents[i];
TSStateId state = ts_stack_top_state(self->stack, slice.version);
Tree *parent = *array_front(&slice.trees);
for (uint32_t j = 0; j < parent->child_count; j++) {
Tree *child = parent->children[j];
pending = child->child_count > 0;
if (child->symbol == ts_builtin_sym_error) {
state = ERROR_STATE;
} else if (!child->extra) {
state = ts_language_next_state(self->language, state, child->symbol);
}
ts_stack_push(self->stack, slice.version, child, pending, state);
}
for (uint32_t j = 1; j < slice.trees.size; j++) {
Tree *tree = slice.trees.contents[j];
parser__push(self, slice.version, tree, state);
}
LOG("breakdown_top_of_stack tree:%s", SYM_NAME(parent->symbol));
LOG_STACK();
ts_stack_decrease_push_count(self->stack, slice.version,
parent->child_count + 1);
ts_tree_release(parent);
array_delete(&slice.trees);
}
} while (pending);
return did_break_down;
}
static bool parser__breakdown_lookahead(Parser *self, Tree **lookahead,
TSStateId state,
ReusableNode *reusable_node) {
bool result = false;
while (reusable_node->tree->child_count > 0 &&
(self->is_split || reusable_node->tree->parse_state != state ||
reusable_node->tree->fragile_left ||
reusable_node->tree->fragile_right)) {
LOG("state_mismatch sym:%s", SYM_NAME(reusable_node->tree->symbol));
reusable_node_breakdown(reusable_node);
result = true;
}
if (result) {
ts_tree_release(*lookahead);
ts_tree_retain(*lookahead = reusable_node->tree);
}
return result;
}
static inline bool ts_lex_mode_eq(TSLexMode self, TSLexMode other) {
return self.lex_state == other.lex_state &&
self.external_lex_state == other.external_lex_state;
}
static bool parser__can_reuse(Parser *self, TSStateId state, Tree *tree,
TableEntry *table_entry) {
TSLexMode current_lex_mode = self->language->lex_modes[state];
if (ts_lex_mode_eq(tree->first_leaf.lex_mode, current_lex_mode))
return true;
if (current_lex_mode.external_lex_state != 0)
return false;
if (tree->size.bytes == 0)
return false;
if (!table_entry->is_reusable)
return false;
if (!table_entry->depends_on_lookahead)
return true;
return tree->child_count > 1 && tree->error_cost == 0;
}
typedef int CondenseResult;
static int CondenseResultMadeChange = 1;
static int CondenseResultAllVersionsHadError = 2;
static CondenseResult parser__condense_stack(Parser *self) {
CondenseResult result = 0;
bool has_version_without_errors = false;
for (StackVersion i = 0; i < ts_stack_version_count(self->stack); i++) {
if (ts_stack_is_halted(self->stack, i)) {
ts_stack_remove_version(self->stack, i);
result |= CondenseResultMadeChange;
i--;
continue;
}
ErrorStatus error_status = ts_stack_error_status(self->stack, i);
if (error_status.count == 0) has_version_without_errors = true;
for (StackVersion j = 0; j < i; j++) {
if (ts_stack_merge(self->stack, j, i)) {
result |= CondenseResultMadeChange;
i--;
break;
}
switch (error_status_compare(error_status,
ts_stack_error_status(self->stack, j))) {
case -1:
ts_stack_remove_version(self->stack, j);
result |= CondenseResultMadeChange;
i--;
j--;
break;
case 1:
ts_stack_remove_version(self->stack, i);
result |= CondenseResultMadeChange;
i--;
break;
}
}
}
if (!has_version_without_errors && ts_stack_version_count(self->stack) > 0) {
result |= CondenseResultAllVersionsHadError;
}
return result;
}
static void parser__restore_external_scanner(Parser *self, StackVersion version) {
const TSExternalTokenState *state = ts_stack_external_token_state(self->stack, version);
if (self->lexer.last_external_token_state != state) {
LOG("restore_external_scanner");
self->lexer.last_external_token_state = state;
if (state) {
self->language->external_scanner.deserialize(
self->external_scanner_payload,
*state
);
} else {
self->language->external_scanner.reset(self->external_scanner_payload);
}
}
}
static Tree *parser__lex(Parser *self, StackVersion version) {
TSStateId parse_state = ts_stack_top_state(self->stack, version);
Length start_position = ts_stack_top_position(self->stack, version);
TSLexMode lex_mode = self->language->lex_modes[parse_state];
const bool *valid_external_tokens = ts_language_enabled_external_tokens(
self->language,
lex_mode.external_lex_state
);
bool found_external_token = false;
bool found_error = false;
bool skipped_error = false;
int32_t first_error_character = 0;
Length error_start_position, error_end_position;
ts_lexer_reset(&self->lexer, start_position);
for (;;) {
Length current_position = self->lexer.current_position;
if (valid_external_tokens) {
LOG("lex_external state:%d, row:%u, column:%u", lex_mode.external_lex_state,
current_position.extent.row, current_position.extent.column);
parser__restore_external_scanner(self, version);
ts_lexer_start(&self->lexer);
if (self->language->external_scanner.scan(self->external_scanner_payload,
&self->lexer.data, valid_external_tokens)) {
if (length_has_unknown_chars(self->lexer.token_end_position)) {
self->lexer.token_end_position = self->lexer.current_position;
}
if (lex_mode.lex_state != 0 ||
self->lexer.token_end_position.bytes > current_position.bytes) {
found_external_token = true;
break;
}
}
ts_lexer_reset(&self->lexer, current_position);
}
LOG("lex_internal state:%d, row:%u, column:%u", lex_mode.lex_state,
current_position.extent.row, current_position.extent.column);
ts_lexer_start(&self->lexer);
if (self->language->lex_fn(&self->lexer.data, lex_mode.lex_state)) {
if (length_has_unknown_chars(self->lexer.token_end_position)) {
self->lexer.token_end_position = self->lexer.current_position;
}
break;
}
if (!found_error) {
LOG("retry_in_error_mode");
found_error = true;
lex_mode = self->language->lex_modes[ERROR_STATE];
valid_external_tokens = ts_language_enabled_external_tokens(
self->language,
lex_mode.external_lex_state
);
ts_lexer_reset(&self->lexer, start_position);
continue;
}
if (!skipped_error) {
LOG("skip_unrecognized_character");
skipped_error = true;
error_start_position = self->lexer.token_start_position;
error_end_position = self->lexer.token_start_position;
first_error_character = self->lexer.data.lookahead;
}
if (self->lexer.current_position.bytes == error_end_position.bytes) {
if (self->lexer.data.lookahead == 0) {
self->lexer.data.result_symbol = ts_builtin_sym_error;
break;
}
self->lexer.data.advance(&self->lexer, false);
}
error_end_position = self->lexer.current_position;
}
Tree *result;
if (skipped_error) {
Length padding = length_sub(error_start_position, start_position);
Length size = length_sub(error_end_position, error_start_position);
result = ts_tree_make_error(size, padding, first_error_character);
} else {
TSSymbol symbol = self->lexer.data.result_symbol;
if (found_external_token) {
symbol = self->language->external_scanner.symbol_map[symbol];
}
Length padding = length_sub(self->lexer.token_start_position, start_position);
Length size = length_sub(self->lexer.token_end_position, self->lexer.token_start_position);
TSSymbolMetadata metadata = ts_language_symbol_metadata(self->language, symbol);
result = ts_tree_make_leaf(symbol, padding, size, metadata);
if (found_external_token) {
result->has_external_tokens = true;
result->has_external_token_state = true;
memset(result->external_token_state, 0, sizeof(TSExternalTokenState));
self->language->external_scanner.serialize(self->external_scanner_payload, result->external_token_state);
self->lexer.last_external_token_state = &result->external_token_state;
}
}
result->bytes_scanned = self->lexer.current_position.bytes - start_position.bytes + 1;
result->parse_state = parse_state;
result->first_leaf.lex_mode = lex_mode;
LOG("lexed_lookahead sym:%s, size:%u", SYM_NAME(result->symbol), result->size.bytes);
return result;
}
static void parser__clear_cached_token(Parser *self) {
ts_tree_release(self->cached_token);
self->cached_token = NULL;
}
static Tree *parser__get_lookahead(Parser *self, StackVersion version,
ReusableNode *reusable_node,
bool *is_fresh) {
Length position = ts_stack_top_position(self->stack, version);
while (reusable_node->tree) {
if (reusable_node->byte_index > position.bytes) {
LOG("before_reusable_node sym:%s", SYM_NAME(reusable_node->tree->symbol));
break;
}
if (reusable_node->byte_index < position.bytes) {
LOG("past_reusable sym:%s", SYM_NAME(reusable_node->tree->symbol));
reusable_node_pop(reusable_node);
continue;
}
if (reusable_node->tree->has_changes) {
LOG("cant_reuse_changed tree:%s, size:%u",
SYM_NAME(reusable_node->tree->symbol),
reusable_node->tree->size.bytes);
if (!reusable_node_breakdown(reusable_node)) {
reusable_node_pop(reusable_node);
parser__breakdown_top_of_stack(self, version);
}
continue;
}
if (reusable_node->tree->symbol == ts_builtin_sym_error) {
LOG("cant_reuse_error tree:%s, size:%u",
SYM_NAME(reusable_node->tree->symbol),
reusable_node->tree->size.bytes);
if (!reusable_node_breakdown(reusable_node)) {
reusable_node_pop(reusable_node);
parser__breakdown_top_of_stack(self, version);
}
continue;
}
if (!ts_external_token_state_eq(
reusable_node->preceding_external_token_state,
ts_stack_external_token_state(self->stack, version))) {
LOG("cant_reuse_external_tokens tree:%s, size:%u",
SYM_NAME(reusable_node->tree->symbol),
reusable_node->tree->size.bytes);
if (!reusable_node_breakdown(reusable_node)) {
reusable_node_pop(reusable_node);
parser__breakdown_top_of_stack(self, version);
}
continue;
}
Tree *result = reusable_node->tree;
ts_tree_retain(result);
return result;
}
if (self->cached_token && position.bytes == self->cached_token_byte_index) {
ts_tree_retain(self->cached_token);
return self->cached_token;
}
*is_fresh = true;
return parser__lex(self, version);
}
static bool parser__select_tree(Parser *self, Tree *left, Tree *right) {
if (!left)
return true;
if (!right)
return false;
if (right->error_cost < left->error_cost) {
LOG("select_smaller_error symbol:%s, over_symbol:%s",
SYM_NAME(right->symbol), SYM_NAME(left->symbol));
return true;
}
if (left->error_cost < right->error_cost) {
LOG("select_smaller_error symbol:%s, over_symbol:%s",
SYM_NAME(left->symbol), SYM_NAME(right->symbol));
return false;
}
int comparison = ts_tree_compare(left, right);
switch (comparison) {
case -1:
LOG("select_earlier symbol:%s, over_symbol:%s", SYM_NAME(left->symbol),
SYM_NAME(right->symbol));
return false;
break;
case 1:
LOG("select_earlier symbol:%s, over_symbol:%s", SYM_NAME(right->symbol),
SYM_NAME(left->symbol));
return true;
default:
LOG("select_existing symbol:%s, over_symbol:%s", SYM_NAME(left->symbol),
SYM_NAME(right->symbol));
return false;
}
}
static bool parser__better_version_exists(Parser *self, StackVersion version,
ErrorStatus my_error_status) {
if (self->finished_tree &&
self->finished_tree->error_cost <= my_error_status.cost)
return true;
for (StackVersion i = 0, n = ts_stack_version_count(self->stack); i < n; i++) {
if (i == version || ts_stack_is_halted(self->stack, i))
continue;
switch (error_status_compare(my_error_status,
ts_stack_error_status(self->stack, i))) {
case -1:
LOG("halt_other version:%u", i);
ts_stack_halt(self->stack, i);
break;
case 1:
return true;
}
}
return false;
}
static void parser__shift(Parser *self, StackVersion version, TSStateId state,
Tree *lookahead, bool extra) {
if (extra != lookahead->extra) {
TSSymbolMetadata metadata =
ts_language_symbol_metadata(self->language, lookahead->symbol);
if (metadata.structural && ts_stack_version_count(self->stack) > 1) {
lookahead = ts_tree_make_copy(lookahead);
} else {
ts_tree_retain(lookahead);
}
lookahead->extra = extra;
} else {
ts_tree_retain(lookahead);
}
bool is_pending = lookahead->child_count > 0;
ts_stack_push(self->stack, version, lookahead, is_pending, state);
if (lookahead->has_external_token_state) {
ts_stack_set_external_token_state(
self->stack, version, ts_tree_last_external_token_state(lookahead));
}
ts_tree_release(lookahead);
}
static bool parser__switch_children(Parser *self, Tree *tree,
Tree **children, uint32_t count) {
self->scratch_tree.symbol = tree->symbol;
self->scratch_tree.child_count = 0;
ts_tree_set_children(&self->scratch_tree, count, children);
if (parser__select_tree(self, tree, &self->scratch_tree)) {
tree->size = self->scratch_tree.size;
tree->padding = self->scratch_tree.padding;
tree->error_cost = self->scratch_tree.error_cost;
tree->children = self->scratch_tree.children;
tree->child_count = self->scratch_tree.child_count;
tree->named_child_count = self->scratch_tree.named_child_count;
tree->visible_child_count = self->scratch_tree.visible_child_count;
return true;
} else {
return false;
}
}
static StackPopResult parser__reduce(Parser *self, StackVersion version,
TSSymbol symbol, unsigned count,
bool fragile, bool allow_skipping) {
uint32_t initial_version_count = ts_stack_version_count(self->stack);
StackPopResult pop = ts_stack_pop_count(self->stack, version, count);
if (pop.stopped_at_error)
return pop;
const TSLanguage *language = self->language;
TSSymbolMetadata metadata = ts_language_symbol_metadata(language, symbol);
for (uint32_t i = 0; i < pop.slices.size; i++) {
StackSlice slice = pop.slices.contents[i];
// Extra tokens on top of the stack should not be included in this new parent
// node. They will be re-pushed onto the stack after the parent node is
// created and pushed.
uint32_t child_count = slice.trees.size;
while (child_count > 0 && slice.trees.contents[child_count - 1]->extra)
child_count--;
Tree *parent = ts_tree_make_node(symbol, child_count, slice.trees.contents, metadata);
// This pop operation may have caused multiple stack versions to collapse
// into one, because they all diverged from a common state. In that case,
// choose one of the arrays of trees to be the parent node's children, and
// delete the rest of the tree arrays.
while (i + 1 < pop.slices.size) {
StackSlice next_slice = pop.slices.contents[i + 1];
if (next_slice.version != slice.version)
break;
i++;
uint32_t child_count = next_slice.trees.size;
while (child_count > 0 && next_slice.trees.contents[child_count - 1]->extra)
child_count--;
if (parser__switch_children(self, parent, next_slice.trees.contents, child_count)) {
ts_tree_array_delete(&slice.trees);
slice = next_slice;
} else {
ts_tree_array_delete(&next_slice.trees);
}
}
TSStateId state = ts_stack_top_state(self->stack, slice.version);
TSStateId next_state = ts_language_next_state(language, state, symbol);
if (fragile || self->is_split || pop.slices.size > 1 || initial_version_count > 1) {
parent->fragile_left = true;
parent->fragile_right = true;
parent->parse_state = TS_TREE_STATE_NONE;
} else {
parent->parse_state = state;
}
// If this pop operation terminated at the end of an error region, then
// create two stack versions: one in which the parent node is interpreted
// normally, and one in which the parent node is skipped.
if (state == ERROR_STATE && allow_skipping && child_count > 1) {
StackVersion other_version = ts_stack_copy_version(self->stack, slice.version);
ts_stack_push(self->stack, other_version, parent, false, ERROR_STATE);
for (uint32_t j = parent->child_count; j < slice.trees.size; j++) {
Tree *tree = slice.trees.contents[j];
ts_stack_push(self->stack, other_version, tree, false, ERROR_STATE);
}
ErrorStatus error_status = ts_stack_error_status(self->stack, other_version);
if (parser__better_version_exists(self, version, error_status))
ts_stack_remove_version(self->stack, other_version);
}
// Push the parent node onto the stack, along with any extra tokens that
// were previously on top of the stack.
parser__push(self, slice.version, parent, next_state);
for (uint32_t j = parent->child_count; j < slice.trees.size; j++) {
Tree *tree = slice.trees.contents[j];
parser__push(self, slice.version, tree, next_state);
}
}
for (StackVersion i = initial_version_count; i < ts_stack_version_count(self->stack); i++) {
for (StackVersion j = initial_version_count; j < i; j++) {
if (ts_stack_merge(self->stack, j, i)) {
i--;
break;
}
}
}
return pop;
}
static inline const TSParseAction *parser__reductions_after_sequence(
Parser *self, TSStateId start_state, const TreeArray *trees_below,
uint32_t tree_count_below, const TreeArray *trees_above,
TSSymbol lookahead_symbol, uint32_t *count) {
TSStateId state = start_state;
uint32_t child_count = 0;
*count = 0;
for (uint32_t i = 0; i < trees_below->size; i++) {
if (child_count == tree_count_below)
break;
Tree *tree = trees_below->contents[trees_below->size - 1 - i];
if (tree->extra) continue;
TSStateId next_state = ts_language_next_state(self->language, state, tree->symbol);
if (next_state == ERROR_STATE)
return NULL;
if (next_state != state) {
child_count++;
state = next_state;
}
}
for (uint32_t i = 0; i < trees_above->size; i++) {
Tree *tree = trees_above->contents[i];
if (tree->extra) continue;
TSStateId next_state = ts_language_next_state(self->language, state, tree->symbol);
if (next_state == ERROR_STATE)
return NULL;
if (next_state != state) {
child_count++;
state = next_state;
}
}
const TSParseAction *actions =
ts_language_actions(self->language, state, lookahead_symbol, count);
if (*count > 0 && actions[*count - 1].type != TSParseActionTypeReduce) {
(*count)--;
}
while (*count > 0 && actions[0].params.child_count < child_count) {
actions++;
(*count)--;
}
while (*count > 0 && actions[*count - 1].params.child_count > child_count) {
(*count)--;
}
return actions;
}
static StackIterateAction parser__repair_error_callback(
void *payload, TSStateId state, TreeArray *trees, uint32_t tree_count,
bool is_done, bool is_pending) {
ErrorRepairSession *session = (ErrorRepairSession *)payload;
Parser *self = session->parser;
TSSymbol lookahead_symbol = session->lookahead_symbol;
ReduceActionSet *repairs = &self->reduce_actions;
TreeArray *trees_above_error = session->trees_above_error;
uint32_t tree_count_above_error = session->tree_count_above_error;
StackIterateAction result = StackIterateNone;
uint32_t last_repair_count = -1;
uint32_t repair_reduction_count = -1;
const TSParseAction *repair_reductions = NULL;
for (uint32_t i = 0; i < repairs->size; i++) {
ReduceAction *repair = &repairs->contents[i];
uint32_t count_needed_below_error = repair->count - tree_count_above_error;
if (count_needed_below_error > tree_count)
break;
uint32_t skip_count = tree_count - count_needed_below_error;
if (session->found_repair && skip_count >= session->best_repair_skip_count) {
array_erase(repairs, i--);
continue;
}
TSStateId state_after_repair = ts_language_next_state(self->language, state, repair->symbol);
if (state == ERROR_STATE || state_after_repair == ERROR_STATE)
continue;
uint32_t action_count;
ts_language_actions(self->language, state_after_repair, lookahead_symbol, &action_count);
if (action_count == 0)
continue;
if (count_needed_below_error != last_repair_count) {
last_repair_count = count_needed_below_error;
repair_reductions = parser__reductions_after_sequence(
self, state, trees, count_needed_below_error, trees_above_error,
lookahead_symbol, &repair_reduction_count);
}
for (uint32_t j = 0; j < repair_reduction_count; j++) {
if (repair_reductions[j].params.symbol == repair->symbol) {
result |= StackIteratePop;
session->found_repair = true;
session->best_repair = *repair;
session->best_repair_skip_count = skip_count;
session->best_repair_next_state = state_after_repair;
array_erase(repairs, i--);
break;
}
}
}
if (repairs->size == 0)
result |= StackIterateStop;
return result;
}
static bool parser__repair_error(Parser *self, StackSlice slice,
TSSymbol lookahead_symbol, TableEntry entry) {
LOG("repair_error");
ErrorRepairSession session = {
.parser = self,
.lookahead_symbol = lookahead_symbol,
.found_repair = false,
.trees_above_error = &slice.trees,
.tree_count_above_error = ts_tree_array_essential_count(&slice.trees),
};
array_clear(&self->reduce_actions);
for (uint32_t i = 0; i < entry.action_count; i++) {
if (entry.actions[i].type == TSParseActionTypeReduce) {
TSSymbol symbol = entry.actions[i].params.symbol;
uint32_t child_count = entry.actions[i].params.child_count;
if ((child_count > session.tree_count_above_error) ||
(child_count == session.tree_count_above_error &&
!ts_language_symbol_metadata(self->language, symbol).visible))
array_push(&self->reduce_actions, ((ReduceAction){
.symbol = symbol,
.count = child_count
}));
}
}
StackPopResult pop = ts_stack_iterate(
self->stack, slice.version, parser__repair_error_callback, &session);
if (!session.found_repair) {
LOG("no_repair_found");
ts_stack_remove_version(self->stack, slice.version);
ts_tree_array_delete(&slice.trees);
return false;
}
ReduceAction repair = session.best_repair;
TSStateId next_state = session.best_repair_next_state;
uint32_t skip_count = session.best_repair_skip_count;
TSSymbol symbol = repair.symbol;
StackSlice new_slice = array_pop(&pop.slices);
TreeArray children = new_slice.trees;
ts_stack_renumber_version(self->stack, new_slice.version, slice.version);
for (uint32_t i = pop.slices.size - 1; i + 1 > 0; i--) {
StackSlice other_slice = pop.slices.contents[i];
ts_tree_array_delete(&other_slice.trees);
if (other_slice.version != pop.slices.contents[i + 1].version)
ts_stack_remove_version(self->stack, other_slice.version);
}
TreeArray skipped_children = ts_tree_array_remove_last_n(&children, skip_count);
TreeArray trailing_extras = ts_tree_array_remove_trailing_extras(&skipped_children);
Tree *error = ts_tree_make_error_node(&skipped_children);
array_push(&children, error);
array_push_all(&children, &trailing_extras);
trailing_extras.size = 0;
array_delete(&trailing_extras);
for (uint32_t i = 0; i < slice.trees.size; i++)
array_push(&children, slice.trees.contents[i]);
array_delete(&slice.trees);
Tree *parent =
ts_tree_make_node(symbol, children.size, children.contents,
ts_language_symbol_metadata(self->language, symbol));
parser__push(self, slice.version, parent, next_state);
ts_stack_decrease_push_count(self->stack, slice.version, error->child_count);
ErrorStatus error_status = ts_stack_error_status(self->stack, slice.version);
if (parser__better_version_exists(self, slice.version, error_status)) {
LOG("no_better_repair_found");
ts_stack_halt(self->stack, slice.version);
return false;
} else {
LOG("repair_found sym:%s, child_count:%u, cost:%u", SYM_NAME(symbol),
repair.count, parent->error_cost);
return true;
}
}
static void parser__start(Parser *self, TSInput input, Tree *previous_tree) {
if (previous_tree) {
LOG("parse_after_edit");
} else {
LOG("new_parse");
}
if (self->language->external_scanner.reset) {
self->language->external_scanner.reset(self->external_scanner_payload);
}
ts_lexer_set_input(&self->lexer, input);
ts_stack_clear(self->stack);
self->reusable_node = reusable_node_new(previous_tree);
self->cached_token = NULL;
self->finished_tree = NULL;
}
static void parser__accept(Parser *self, StackVersion version,
Tree *lookahead) {
lookahead->extra = true;
assert(lookahead->symbol == ts_builtin_sym_end);
ts_stack_push(self->stack, version, lookahead, false, 1);
StackPopResult pop = ts_stack_pop_all(self->stack, version);
for (uint32_t i = 0; i < pop.slices.size; i++) {
StackSlice slice = pop.slices.contents[i];
TreeArray trees = slice.trees;
Tree *root = NULL;
if (trees.size == 1) {
root = trees.contents[0];
array_delete(&trees);
} else {
for (uint32_t j = trees.size - 1; j + 1 > 0; j--) {
Tree *child = trees.contents[j];
if (!child->extra) {
root = ts_tree_make_copy(child);
root->child_count = 0;
for (uint32_t k = 0; k < child->child_count; k++)
ts_tree_retain(child->children[k]);
array_splice(&trees, j, 1, child->child_count, child->children);
ts_tree_set_children(root, trees.size, trees.contents);
ts_tree_release(child);
break;
}
}
}
if (parser__select_tree(self, self->finished_tree, root)) {
ts_tree_release(self->finished_tree);
assert(root->ref_count > 0);
self->finished_tree = root;
} else {
ts_tree_release(root);
}
}
ts_stack_remove_version(self->stack, pop.slices.contents[0].version);
ts_stack_halt(self->stack, version);
}
static bool parser__do_potential_reductions(Parser *self, StackVersion version) {
bool has_shift_action = false;
TSStateId state = ts_stack_top_state(self->stack, version);
uint32_t previous_version_count = ts_stack_version_count(self->stack);
array_clear(&self->reduce_actions);
for (TSSymbol symbol = 0; symbol < self->language->token_count; symbol++) {
TableEntry entry;
ts_language_table_entry(self->language, state, symbol, &entry);
for (uint32_t i = 0; i < entry.action_count; i++) {
TSParseAction action = entry.actions[i];
if (action.extra)
continue;
switch (action.type) {
case TSParseActionTypeShift:
case TSParseActionTypeRecover:
has_shift_action = true;
break;
case TSParseActionTypeReduce:
if (action.params.child_count > 0)
ts_reduce_action_set_add(&self->reduce_actions, (ReduceAction){
.symbol = action.params.symbol,
.count = action.params.child_count,
});
default:
break;
}
}
}
bool did_reduce = false;
for (uint32_t i = 0; i < self->reduce_actions.size; i++) {
ReduceAction action = self->reduce_actions.contents[i];
StackPopResult reduction =
parser__reduce(self, version, action.symbol, action.count, true, false);
if (reduction.stopped_at_error) {
ts_tree_array_delete(&reduction.slices.contents[0].trees);
ts_stack_remove_version(self->stack, reduction.slices.contents[0].version);
continue;
} else {
did_reduce = true;
}
}
if (did_reduce) {
if (has_shift_action) {
return true;
} else {
ts_stack_renumber_version(self->stack, previous_version_count, version);
return false;
}
} else {
return true;
}
}
static StackIterateAction parser__skip_preceding_trees_callback(
void *payload, TSStateId state, TreeArray *trees, uint32_t tree_count,
bool is_done, bool is_pending) {
if (tree_count > 0 && state != ERROR_STATE) {
uint32_t bytes_skipped = 0;
for (uint32_t i = 0; i < trees->size; i++) {
bytes_skipped += ts_tree_total_bytes(trees->contents[i]);
}
if (bytes_skipped == 0) return StackIterateNone;
SkipPrecedingTreesSession *session = payload;
Parser *self = session->parser;
TSSymbol lookahead_symbol = session->lookahead_symbol;
uint32_t action_count;
const TSParseAction *actions =
ts_language_actions(self->language, state, lookahead_symbol, &action_count);
if (action_count > 0 && actions[0].type == TSParseActionTypeReduce) {
return StackIteratePop | StackIterateStop;
}
}
return StackIterateNone;
}
static bool parser__skip_preceding_trees(Parser *self, StackVersion version,
TSSymbol lookahead_symbol) {
SkipPrecedingTreesSession session = { self, lookahead_symbol };
StackPopResult pop = ts_stack_iterate(
self->stack, version, parser__skip_preceding_trees_callback, &session);
StackVersion previous_version = STACK_VERSION_NONE;
for (uint32_t i = 0; i < pop.slices.size; i++) {
StackSlice slice = pop.slices.contents[i];
if (slice.version == previous_version) {
ts_tree_array_delete(&slice.trees);
continue;
}
previous_version = slice.version;
Tree *error = ts_tree_make_error_node(&slice.trees);
error->extra = true;
TSStateId state = ts_stack_top_state(self->stack, slice.version);
parser__push(self, slice.version, error, state);
}
return pop.slices.size > 0;
}
static void parser__handle_error(Parser *self, StackVersion version,
TSSymbol lookahead_symbol) {
// If there are other stack versions that are clearly better than this one,
// just halt this version.
ErrorStatus error_status = ts_stack_error_status(self->stack, version);
error_status.count++;
if (parser__better_version_exists(self, version, error_status)) {
ts_stack_halt(self->stack, version);
LOG("bail_on_error");
return;
}
LOG("handle_error");
// If the current lookahead symbol would have been valid in some previous
// state on the stack, create one stack version that repairs the error
// immediately by simply skipping all of the trees that came after that state.
if (parser__skip_preceding_trees(self, version, lookahead_symbol)) {
LOG("skip_preceding_trees");
LOG_STACK();
}
// Perform any reductions that could have happened in this state, regardless
// of the lookahead.
uint32_t previous_version_count = ts_stack_version_count(self->stack);
for (StackVersion v = version; v < ts_stack_version_count(self->stack);) {
if (parser__do_potential_reductions(self, v)) {
if (v == version) {
v = previous_version_count;
} else {
v++;
}
}
}
// Push a discontinuity onto the stack. Merge all of the stack versions that
// were created in the previous step.
ts_stack_push(self->stack, version, NULL, false, ERROR_STATE);
while (ts_stack_version_count(self->stack) > previous_version_count) {
ts_stack_push(self->stack, previous_version_count, NULL, false, ERROR_STATE);
assert(ts_stack_merge(self->stack, version, previous_version_count));
}
}
static void parser__halt_parse(Parser *self) {
LOG("halting_parse");
LOG_STACK();
ts_lexer_advance_to_end(&self->lexer);
Length remaining_length = length_sub(
self->lexer.current_position,
ts_stack_top_position(self->stack, 0)
);
Tree *filler_node = ts_tree_make_error(remaining_length, length_zero(), 0);
filler_node->visible = false;
parser__push(self, 0, filler_node, 0);
TreeArray children = array_new();
Tree *root_error = ts_tree_make_error_node(&children);
parser__push(self, 0, root_error, 0);
TSSymbolMetadata metadata = ts_language_symbol_metadata(self->language, ts_builtin_sym_end);
Tree *eof = ts_tree_make_leaf(ts_builtin_sym_end, length_zero(), length_zero(), metadata);
parser__accept(self, 0, eof);
ts_tree_release(eof);
}
static void parser__recover(Parser *self, StackVersion version, TSStateId state,
Tree *lookahead) {
if (lookahead->symbol == ts_builtin_sym_end) {
LOG("recover_eof");
TreeArray children = array_new();
Tree *parent = ts_tree_make_error_node(&children);
parser__push(self, version, parent, 1);
parser__accept(self, version, lookahead);
}
LOG("recover state:%u", state);
StackVersion new_version = ts_stack_copy_version(self->stack, version);
parser__shift(
self, new_version, ERROR_STATE, lookahead,
ts_language_symbol_metadata(self->language, lookahead->symbol).extra);
ErrorStatus error_status = ts_stack_error_status(self->stack, new_version);
if (parser__better_version_exists(self, version, error_status)) {
ts_stack_remove_version(self->stack, new_version);
LOG("bail_on_recovery");
}
parser__shift(self, version, state, lookahead, false);
}
static void parser__advance(Parser *self, StackVersion version,
ReusableNode *reusable_node) {
bool validated_lookahead = false;
Tree *lookahead = parser__get_lookahead(self, version, reusable_node, &validated_lookahead);
for (;;) {
TSStateId state = ts_stack_top_state(self->stack, version);
TableEntry table_entry;
ts_language_table_entry(self->language, state, lookahead->first_leaf.symbol, &table_entry);
if (!validated_lookahead) {
if (!parser__can_reuse(self, state, lookahead, &table_entry)) {
if (lookahead == reusable_node->tree) {
reusable_node_pop_leaf(reusable_node);
} else {
parser__clear_cached_token(self);
}
ts_tree_release(lookahead);
lookahead = parser__get_lookahead(self, version, reusable_node, &validated_lookahead);
continue;
}
validated_lookahead = true;
LOG("reused_lookahead sym:%s, size:%u", SYM_NAME(lookahead->symbol), lookahead->size.bytes);
}
bool reduction_stopped_at_error = false;
StackVersion last_reduction_version = STACK_VERSION_NONE;
for (uint32_t i = 0; i < table_entry.action_count; i++) {
TSParseAction action = table_entry.actions[i];
switch (action.type) {
case TSParseActionTypeShift: {
bool extra = action.extra;
TSStateId next_state;
if (action.extra) {
next_state = state;
LOG("shift_extra");
} else {
next_state = action.params.to_state;
LOG("shift state:%u", next_state);
}
if (lookahead->child_count > 0) {
if (parser__breakdown_lookahead(self, &lookahead, state, reusable_node)) {
if (!parser__can_reuse(self, state, lookahead, &table_entry)) {
reusable_node_pop(reusable_node);
ts_tree_release(lookahead);
lookahead = parser__get_lookahead(self, version, reusable_node, &validated_lookahead);
}
}
next_state = ts_language_next_state(self->language, state, lookahead->symbol);
}
parser__shift(self, version, next_state, lookahead, extra);
if (lookahead == reusable_node->tree)
reusable_node_pop(reusable_node);
ts_tree_release(lookahead);
return;
}
case TSParseActionTypeReduce: {
if (reduction_stopped_at_error)
continue;
unsigned child_count = action.params.child_count;
TSSymbol symbol = action.params.symbol;
bool fragile = action.fragile;
LOG("reduce sym:%s, child_count:%u", SYM_NAME(symbol), child_count);
StackPopResult reduction =
parser__reduce(self, version, symbol, child_count, fragile, true);
StackSlice slice = *array_front(&reduction.slices);
if (reduction.stopped_at_error) {
reduction_stopped_at_error = true;
if (!parser__repair_error(self, slice, lookahead->first_leaf.symbol,
table_entry))
break;
}
last_reduction_version = slice.version;
break;
}
case TSParseActionTypeAccept: {
if (ts_stack_error_status(self->stack, version).count > 0)
continue;
LOG("accept");
parser__accept(self, version, lookahead);
ts_tree_release(lookahead);
return;
}
case TSParseActionTypeRecover: {
while (lookahead->child_count > 0) {
reusable_node_breakdown(reusable_node);
ts_tree_release(lookahead);
lookahead = reusable_node->tree;
ts_tree_retain(lookahead);
}
parser__recover(self, version, action.params.to_state, lookahead);
if (lookahead == reusable_node->tree)
reusable_node_pop(reusable_node);
ts_tree_release(lookahead);
return;
}
}
}
if (last_reduction_version != STACK_VERSION_NONE) {
ts_stack_renumber_version(self->stack, last_reduction_version, version);
LOG_STACK();
continue;
}
if (parser__breakdown_top_of_stack(self, version)) {
continue;
}
if (state == ERROR_STATE) {
parser__push(self, version, lookahead, ERROR_STATE);
return;
}
parser__handle_error(self, version, lookahead->first_leaf.symbol);
if (ts_stack_is_halted(self->stack, version)) {
ts_tree_release(lookahead);
return;
}
}
}
bool parser_init(Parser *self) {
ts_lexer_init(&self->lexer);
array_init(&self->reduce_actions);
array_init(&self->tree_path1);
array_init(&self->tree_path2);
array_grow(&self->reduce_actions, 4);
self->stack = ts_stack_new();
self->finished_tree = NULL;
return true;
}
void parser_set_language(Parser *self, const TSLanguage *language) {
if (self->external_scanner_payload && self->language->external_scanner.destroy)
self->language->external_scanner.destroy(self->external_scanner_payload);
if (language && language->external_scanner.create)
self->external_scanner_payload = language->external_scanner.create();
else
self->external_scanner_payload = NULL;
self->language = language;
}
void parser_destroy(Parser *self) {
if (self->stack)
ts_stack_delete(self->stack);
if (self->reduce_actions.contents)
array_delete(&self->reduce_actions);
if (self->tree_path1.contents)
array_delete(&self->tree_path1);
if (self->tree_path2.contents)
array_delete(&self->tree_path2);
parser_set_language(self, NULL);
}
Tree *parser_parse(Parser *self, TSInput input, Tree *old_tree, bool halt_on_error) {
parser__start(self, input, old_tree);
StackVersion version = STACK_VERSION_NONE;
uint32_t position = 0, last_position = 0;
ReusableNode reusable_node;
do {
for (version = 0; version < ts_stack_version_count(self->stack); version++) {
reusable_node = self->reusable_node;
last_position = position;
while (!ts_stack_is_halted(self->stack, version)) {
position = ts_stack_top_position(self->stack, version).chars;
if (position > last_position || (version > 0 && position == last_position))
break;
LOG("process version:%d, version_count:%u, state:%d, row:%u, col:%u",
version, ts_stack_version_count(self->stack),
ts_stack_top_state(self->stack, version),
ts_stack_top_position(self->stack, version).extent.row,
ts_stack_top_position(self->stack, version).extent.column);
parser__advance(self, version, &reusable_node);
LOG_STACK();
}
}
self->reusable_node = reusable_node;
CondenseResult condense_result = parser__condense_stack(self);
if (halt_on_error && (condense_result & CondenseResultAllVersionsHadError)) {
parser__halt_parse(self);
break;
}
if (condense_result & CondenseResultMadeChange) {
LOG("condense");
LOG_STACK();
}
self->is_split = (version > 1);
} while (version != 0);
LOG("done");
LOG_TREE();
ts_stack_clear(self->stack);
parser__clear_cached_token(self);
ts_tree_assign_parents(self->finished_tree, &self->tree_path1);
return self->finished_tree;
}
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