1 files changed, 2151 insertions, 0 deletions

diff --git a/vendor/github.com/mitjafelicijan/go-tree-sitter/parser.c b/vendor/github.com/mitjafelicijan/go-tree-sitter/parser.c
new file mode 100644
index 0000000..a72983d
--- /dev/null
+++ b/vendor/github.com/mitjafelicijan/go-tree-sitter/parser.c
@@ -0,0 +1,2151 @@
+#define _POSIX_C_SOURCE 200112L
+
+#include <time.h>
+#include <assert.h>
+#include <stdio.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <inttypes.h>
+#include "api.h"
+#include "./alloc.h"
+#include "./array.h"
+#include "./atomic.h"
+#include "./clock.h"
+#include "./error_costs.h"
+#include "./get_changed_ranges.h"
+#include "./language.h"
+#include "./length.h"
+#include "./lexer.h"
+#include "./reduce_action.h"
+#include "./reusable_node.h"
+#include "./stack.h"
+#include "./subtree.h"
+#include "./tree.h"
+#include "./wasm_store.h"
+
+#define LOG(...)                                                                            \
+  if (self->lexer.logger.log || self->dot_graph_file) {                                     \
+    snprintf(self->lexer.debug_buffer, TREE_SITTER_SERIALIZATION_BUFFER_SIZE, __VA_ARGS__); \
+    ts_parser__log(self);                                                                   \
+  }
+
+#define LOG_LOOKAHEAD(symbol_name, size)                      \
+  if (self->lexer.logger.log || self->dot_graph_file) {       \
+    char *buf = self->lexer.debug_buffer;                     \
+    const char *symbol = symbol_name;                         \
+    int off = sprintf(buf, "lexed_lookahead sym:");           \
+    for (                                                     \
+      int i = 0;                                              \
+      symbol[i] != '\0'                                       \
+      && off < TREE_SITTER_SERIALIZATION_BUFFER_SIZE;         \
+      i++                                                     \
+    ) {                                                       \
+      switch (symbol[i]) {                                    \
+      case '\t': buf[off++] = '\\'; buf[off++] = 't'; break;  \
+      case '\n': buf[off++] = '\\'; buf[off++] = 'n'; break;  \
+      case '\v': buf[off++] = '\\'; buf[off++] = 'v'; break;  \
+      case '\f': buf[off++] = '\\'; buf[off++] = 'f'; break;  \
+      case '\r': buf[off++] = '\\'; buf[off++] = 'r'; break;  \
+      case '\\': buf[off++] = '\\'; buf[off++] = '\\'; break; \
+      default:   buf[off++] = symbol[i]; break;               \
+      }                                                       \
+    }                                                         \
+    snprintf(                                                 \
+      buf + off,                                              \
+      TREE_SITTER_SERIALIZATION_BUFFER_SIZE - off,            \
+      ", size:%u",                                            \
+      size                                                    \
+    );                                                        \
+    ts_parser__log(self);                                     \
+  }
+
+#define LOG_STACK()                                                              \
+  if (self->dot_graph_file) {                                                    \
+    ts_stack_print_dot_graph(self->stack, self->language, self->dot_graph_file); \
+    fputs("\n\n", self->dot_graph_file);                                         \
+  }
+
+#define LOG_TREE(tree)                                                      \
+  if (self->dot_graph_file) {                                               \
+    ts_subtree_print_dot_graph(tree, self->language, self->dot_graph_file); \
+    fputs("\n", self->dot_graph_file);                                      \
+  }
+
+#define SYM_NAME(symbol) ts_language_symbol_name(self->language, symbol)
+
+#define TREE_NAME(tree) SYM_NAME(ts_subtree_symbol(tree))
+
+static const unsigned MAX_VERSION_COUNT = 6;
+static const unsigned MAX_VERSION_COUNT_OVERFLOW = 4;
+static const unsigned MAX_SUMMARY_DEPTH = 16;
+static const unsigned MAX_COST_DIFFERENCE = 16 * ERROR_COST_PER_SKIPPED_TREE;
+static const unsigned OP_COUNT_PER_TIMEOUT_CHECK = 100;
+
+typedef struct {
+  Subtree token;
+  Subtree last_external_token;
+  uint32_t byte_index;
+} TokenCache;
+
+struct TSParser {
+  Lexer lexer;
+  Stack *stack;
+  SubtreePool tree_pool;
+  const TSLanguage *language;
+  TSWasmStore *wasm_store;
+  ReduceActionSet reduce_actions;
+  Subtree finished_tree;
+  SubtreeArray trailing_extras;
+  SubtreeArray trailing_extras2;
+  SubtreeArray scratch_trees;
+  TokenCache token_cache;
+  ReusableNode reusable_node;
+  void *external_scanner_payload;
+  FILE *dot_graph_file;
+  TSClock end_clock;
+  TSDuration timeout_duration;
+  unsigned accept_count;
+  unsigned operation_count;
+  const volatile size_t *cancellation_flag;
+  Subtree old_tree;
+  TSRangeArray included_range_differences;
+  unsigned included_range_difference_index;
+  bool has_scanner_error;
+};
+
+typedef struct {
+  unsigned cost;
+  unsigned node_count;
+  int dynamic_precedence;
+  bool is_in_error;
+} ErrorStatus;
+
+typedef enum {
+  ErrorComparisonTakeLeft,
+  ErrorComparisonPreferLeft,
+  ErrorComparisonNone,
+  ErrorComparisonPreferRight,
+  ErrorComparisonTakeRight,
+} ErrorComparison;
+
+typedef struct {
+  const char *string;
+  uint32_t length;
+} TSStringInput;
+
+// StringInput
+
+static const char *ts_string_input_read(
+  void *_self,
+  uint32_t byte,
+  TSPoint point,
+  uint32_t *length
+) {
+  (void)point;
+  TSStringInput *self = (TSStringInput *)_self;
+  if (byte >= self->length) {
+    *length = 0;
+    return "";
+  } else {
+    *length = self->length - byte;
+    return self->string + byte;
+  }
+}
+
+// Parser - Private
+
+static void ts_parser__log(TSParser *self) {
+  if (self->lexer.logger.log) {
+    self->lexer.logger.log(
+      self->lexer.logger.payload,
+      TSLogTypeParse,
+      self->lexer.debug_buffer
+    );
+  }
+
+  if (self->dot_graph_file) {
+    fprintf(self->dot_graph_file, "graph {\nlabel=\"");
+    for (char *chr = &self->lexer.debug_buffer[0]; *chr != 0; chr++) {
+      if (*chr == '"' || *chr == '\\') fputc('\\', self->dot_graph_file);
+      fputc(*chr, self->dot_graph_file);
+    }
+    fprintf(self->dot_graph_file, "\"\n}\n\n");
+  }
+}
+
+static bool ts_parser__breakdown_top_of_stack(
+  TSParser *self,
+  StackVersion version
+) {
+  bool did_break_down = false;
+  bool pending = false;
+
+  do {
+    StackSliceArray pop = ts_stack_pop_pending(self->stack, version);
+    if (!pop.size) break;
+
+    did_break_down = true;
+    pending = false;
+    for (uint32_t i = 0; i < pop.size; i++) {
+      StackSlice slice = pop.contents[i];
+      TSStateId state = ts_stack_state(self->stack, slice.version);
+      Subtree parent = *array_front(&slice.subtrees);
+
+      for (uint32_t j = 0, n = ts_subtree_child_count(parent); j < n; j++) {
+        Subtree child = ts_subtree_children(parent)[j];
+        pending = ts_subtree_child_count(child) > 0;
+
+        if (ts_subtree_is_error(child)) {
+          state = ERROR_STATE;
+        } else if (!ts_subtree_extra(child)) {
+          state = ts_language_next_state(self->language, state, ts_subtree_symbol(child));
+        }
+
+        ts_subtree_retain(child);
+        ts_stack_push(self->stack, slice.version, child, pending, state);
+      }
+
+      for (uint32_t j = 1; j < slice.subtrees.size; j++) {
+        Subtree tree = slice.subtrees.contents[j];
+        ts_stack_push(self->stack, slice.version, tree, false, state);
+      }
+
+      ts_subtree_release(&self->tree_pool, parent);
+      array_delete(&slice.subtrees);
+
+      LOG("breakdown_top_of_stack tree:%s", TREE_NAME(parent));
+      LOG_STACK();
+    }
+  } while (pending);
+
+  return did_break_down;
+}
+
+static void ts_parser__breakdown_lookahead(
+  TSParser *self,
+  Subtree *lookahead,
+  TSStateId state,
+  ReusableNode *reusable_node
+) {
+  bool did_descend = false;
+  Subtree tree = reusable_node_tree(reusable_node);
+  while (ts_subtree_child_count(tree) > 0 && ts_subtree_parse_state(tree) != state) {
+    LOG("state_mismatch sym:%s", TREE_NAME(tree));
+    reusable_node_descend(reusable_node);
+    tree = reusable_node_tree(reusable_node);
+    did_descend = true;
+  }
+
+  if (did_descend) {
+    ts_subtree_release(&self->tree_pool, *lookahead);
+    *lookahead = tree;
+    ts_subtree_retain(*lookahead);
+  }
+}
+
+static ErrorComparison ts_parser__compare_versions(
+  TSParser *self,
+  ErrorStatus a,
+  ErrorStatus b
+) {
+  (void)self;
+  if (!a.is_in_error && b.is_in_error) {
+    if (a.cost < b.cost) {
+      return ErrorComparisonTakeLeft;
+    } else {
+      return ErrorComparisonPreferLeft;
+    }
+  }
+
+  if (a.is_in_error && !b.is_in_error) {
+    if (b.cost < a.cost) {
+      return ErrorComparisonTakeRight;
+    } else {
+      return ErrorComparisonPreferRight;
+    }
+  }
+
+  if (a.cost < b.cost) {
+    if ((b.cost - a.cost) * (1 + a.node_count) > MAX_COST_DIFFERENCE) {
+      return ErrorComparisonTakeLeft;
+    } else {
+      return ErrorComparisonPreferLeft;
+    }
+  }
+
+  if (b.cost < a.cost) {
+    if ((a.cost - b.cost) * (1 + b.node_count) > MAX_COST_DIFFERENCE) {
+      return ErrorComparisonTakeRight;
+    } else {
+      return ErrorComparisonPreferRight;
+    }
+  }
+
+  if (a.dynamic_precedence > b.dynamic_precedence) return ErrorComparisonPreferLeft;
+  if (b.dynamic_precedence > a.dynamic_precedence) return ErrorComparisonPreferRight;
+  return ErrorComparisonNone;
+}
+
+static ErrorStatus ts_parser__version_status(
+  TSParser *self,
+  StackVersion version
+) {
+  unsigned cost = ts_stack_error_cost(self->stack, version);
+  bool is_paused = ts_stack_is_paused(self->stack, version);
+  if (is_paused) cost += ERROR_COST_PER_SKIPPED_TREE;
+  return (ErrorStatus) {
+    .cost = cost,
+    .node_count = ts_stack_node_count_since_error(self->stack, version),
+    .dynamic_precedence = ts_stack_dynamic_precedence(self->stack, version),
+    .is_in_error = is_paused || ts_stack_state(self->stack, version) == ERROR_STATE
+  };
+}
+
+static bool ts_parser__better_version_exists(
+  TSParser *self,
+  StackVersion version,
+  bool is_in_error,
+  unsigned cost
+) {
+  if (self->finished_tree.ptr && ts_subtree_error_cost(self->finished_tree) <= cost) {
+    return true;
+  }
+
+  Length position = ts_stack_position(self->stack, version);
+  ErrorStatus status = {
+    .cost = cost,
+    .is_in_error = is_in_error,
+    .dynamic_precedence = ts_stack_dynamic_precedence(self->stack, version),
+    .node_count = ts_stack_node_count_since_error(self->stack, version),
+  };
+
+  for (StackVersion i = 0, n = ts_stack_version_count(self->stack); i < n; i++) {
+    if (i == version ||
+        !ts_stack_is_active(self->stack, i) ||
+        ts_stack_position(self->stack, i).bytes < position.bytes) continue;
+    ErrorStatus status_i = ts_parser__version_status(self, i);
+    switch (ts_parser__compare_versions(self, status, status_i)) {
+      case ErrorComparisonTakeRight:
+        return true;
+      case ErrorComparisonPreferRight:
+        if (ts_stack_can_merge(self->stack, i, version)) return true;
+        break;
+      default:
+        break;
+    }
+  }
+
+  return false;
+}
+
+static bool ts_parser__call_main_lex_fn(TSParser *self, TSLexMode lex_mode) {
+  if (ts_language_is_wasm(self->language)) {
+    return ts_wasm_store_call_lex_main(self->wasm_store, lex_mode.lex_state);
+  } else {
+    return self->language->lex_fn(&self->lexer.data, lex_mode.lex_state);
+  }
+}
+
+static bool ts_parser__call_keyword_lex_fn(TSParser *self, TSLexMode lex_mode) {
+  if (ts_language_is_wasm(self->language)) {
+    return ts_wasm_store_call_lex_keyword(self->wasm_store, 0);
+  } else {
+    return self->language->keyword_lex_fn(&self->lexer.data, 0);
+  }
+}
+
+static void ts_parser__external_scanner_create(
+  TSParser *self
+) {
+  if (self->language && self->language->external_scanner.states) {
+    if (ts_language_is_wasm(self->language)) {
+      self->external_scanner_payload = (void *)(uintptr_t)ts_wasm_store_call_scanner_create(
+        self->wasm_store
+      );
+      if (ts_wasm_store_has_error(self->wasm_store)) {
+        self->has_scanner_error = true;
+      }
+    } else if (self->language->external_scanner.create) {
+      self->external_scanner_payload = self->language->external_scanner.create();
+    }
+  }
+}
+
+static void ts_parser__external_scanner_destroy(
+  TSParser *self
+) {
+  if (
+    self->language &&
+    self->external_scanner_payload &&
+    self->language->external_scanner.destroy &&
+    !ts_language_is_wasm(self->language)
+  ) {
+    self->language->external_scanner.destroy(
+      self->external_scanner_payload
+    );
+  }
+  self->external_scanner_payload = NULL;
+}
+
+static unsigned ts_parser__external_scanner_serialize(
+  TSParser *self
+) {
+  if (ts_language_is_wasm(self->language)) {
+    return ts_wasm_store_call_scanner_serialize(
+      self->wasm_store,
+      (uintptr_t)self->external_scanner_payload,
+      self->lexer.debug_buffer
+    );
+  } else {
+    return self->language->external_scanner.serialize(
+      self->external_scanner_payload,
+      self->lexer.debug_buffer
+    );
+  }
+}
+
+static void ts_parser__external_scanner_deserialize(
+  TSParser *self,
+  Subtree external_token
+) {
+  const char *data = NULL;
+  uint32_t length = 0;
+  if (external_token.ptr) {
+    data = ts_external_scanner_state_data(&external_token.ptr->external_scanner_state);
+    length = external_token.ptr->external_scanner_state.length;
+  }
+
+  if (ts_language_is_wasm(self->language)) {
+    ts_wasm_store_call_scanner_deserialize(
+      self->wasm_store,
+      (uintptr_t)self->external_scanner_payload,
+      data,
+      length
+    );
+    if (ts_wasm_store_has_error(self->wasm_store)) {
+      self->has_scanner_error = true;
+    }
+  } else {
+    self->language->external_scanner.deserialize(
+      self->external_scanner_payload,
+      data,
+      length
+    );
+  }
+}
+
+static bool ts_parser__external_scanner_scan(
+  TSParser *self,
+  TSStateId external_lex_state
+) {
+  if (ts_language_is_wasm(self->language)) {
+    bool result = ts_wasm_store_call_scanner_scan(
+      self->wasm_store,
+      (uintptr_t)self->external_scanner_payload,
+      external_lex_state * self->language->external_token_count
+    );
+    if (ts_wasm_store_has_error(self->wasm_store)) {
+      self->has_scanner_error = true;
+    }
+    return result;
+  } else {
+    const bool *valid_external_tokens = ts_language_enabled_external_tokens(
+      self->language,
+      external_lex_state
+    );
+    return self->language->external_scanner.scan(
+      self->external_scanner_payload,
+      &self->lexer.data,
+      valid_external_tokens
+    );
+  }
+}
+
+static bool ts_parser__can_reuse_first_leaf(
+  TSParser *self,
+  TSStateId state,
+  Subtree tree,
+  TableEntry *table_entry
+) {
+  TSLexMode current_lex_mode = self->language->lex_modes[state];
+  TSSymbol leaf_symbol = ts_subtree_leaf_symbol(tree);
+  TSStateId leaf_state = ts_subtree_leaf_parse_state(tree);
+  TSLexMode leaf_lex_mode = self->language->lex_modes[leaf_state];
+
+  // At the end of a non-terminal extra node, the lexer normally returns
+  // NULL, which indicates that the parser should look for a reduce action
+  // at symbol `0`. Avoid reusing tokens in this situation to ensure that
+  // the same thing happens when incrementally reparsing.
+  if (current_lex_mode.lex_state == (uint16_t)(-1)) return false;
+
+  // If the token was created in a state with the same set of lookaheads, it is reusable.
+  if (
+    table_entry->action_count > 0 &&
+    memcmp(&leaf_lex_mode, &current_lex_mode, sizeof(TSLexMode)) == 0 &&
+    (
+      leaf_symbol != self->language->keyword_capture_token ||
+      (!ts_subtree_is_keyword(tree) && ts_subtree_parse_state(tree) == state)
+    )
+  ) return true;
+
+  // Empty tokens are not reusable in states with different lookaheads.
+  if (ts_subtree_size(tree).bytes == 0 && leaf_symbol != ts_builtin_sym_end) return false;
+
+  // If the current state allows external tokens or other tokens that conflict with this
+  // token, this token is not reusable.
+  return current_lex_mode.external_lex_state == 0 && table_entry->is_reusable;
+}
+
+static Subtree ts_parser__lex(
+  TSParser *self,
+  StackVersion version,
+  TSStateId parse_state
+) {
+  TSLexMode lex_mode = self->language->lex_modes[parse_state];
+  if (lex_mode.lex_state == (uint16_t)-1) {
+    LOG("no_lookahead_after_non_terminal_extra");
+    return NULL_SUBTREE;
+  }
+
+  const Length start_position = ts_stack_position(self->stack, version);
+  const Subtree external_token = ts_stack_last_external_token(self->stack, version);
+
+  bool found_external_token = false;
+  bool error_mode = parse_state == ERROR_STATE;
+  bool skipped_error = false;
+  bool called_get_column = false;
+  int32_t first_error_character = 0;
+  Length error_start_position = length_zero();
+  Length error_end_position = length_zero();
+  uint32_t lookahead_end_byte = 0;
+  uint32_t external_scanner_state_len = 0;
+  bool external_scanner_state_changed = false;
+  ts_lexer_reset(&self->lexer, start_position);
+
+  for (;;) {
+    bool found_token = false;
+    Length current_position = self->lexer.current_position;
+
+    if (lex_mode.external_lex_state != 0) {
+      LOG(
+        "lex_external state:%d, row:%u, column:%u",
+        lex_mode.external_lex_state,
+        current_position.extent.row,
+        current_position.extent.column
+      );
+      ts_lexer_start(&self->lexer);
+      ts_parser__external_scanner_deserialize(self, external_token);
+      found_token = ts_parser__external_scanner_scan(self, lex_mode.external_lex_state);
+      if (self->has_scanner_error) return NULL_SUBTREE;
+      ts_lexer_finish(&self->lexer, &lookahead_end_byte);
+
+      if (found_token) {
+        external_scanner_state_len = ts_parser__external_scanner_serialize(self);
+        external_scanner_state_changed = !ts_external_scanner_state_eq(
+          ts_subtree_external_scanner_state(external_token),
+          self->lexer.debug_buffer,
+          external_scanner_state_len
+        );
+
+        // When recovering from an error, ignore any zero-length external tokens
+        // unless they have changed the external scanner's state. This helps to
+        // avoid infinite loops which could otherwise occur, because the lexer is
+        // looking for any possible token, instead of looking for the specific set of
+        // tokens that are valid in some parse state.
+        //
+        // Note that it's possible that the token end position may be *before* the
+        // original position of the lexer because of the way that tokens are positioned
+        // at included range boundaries: when a token is terminated at the start of
+        // an included range, it is marked as ending at the *end* of the preceding
+        // included range.
+        if (
+          self->lexer.token_end_position.bytes <= current_position.bytes &&
+          (error_mode || !ts_stack_has_advanced_since_error(self->stack, version)) &&
+          !external_scanner_state_changed
+        ) {
+          LOG(
+            "ignore_empty_external_token symbol:%s",
+            SYM_NAME(self->language->external_scanner.symbol_map[self->lexer.data.result_symbol])
+          )
+          found_token = false;
+        }
+      }
+
+      if (found_token) {
+        found_external_token = true;
+        called_get_column = self->lexer.did_get_column;
+        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);
+    found_token = ts_parser__call_main_lex_fn(self, lex_mode);
+    ts_lexer_finish(&self->lexer, &lookahead_end_byte);
+    if (found_token) break;
+
+    if (!error_mode) {
+      error_mode = true;
+      lex_mode = self->language->lex_modes[ERROR_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.eof(&self->lexer.data)) {
+        self->lexer.data.result_symbol = ts_builtin_sym_error;
+        break;
+      }
+      self->lexer.data.advance(&self->lexer.data, false);
+    }
+
+    error_end_position = self->lexer.current_position;
+  }
+
+  Subtree result;
+  if (skipped_error) {
+    Length padding = length_sub(error_start_position, start_position);
+    Length size = length_sub(error_end_position, error_start_position);
+    uint32_t lookahead_bytes = lookahead_end_byte - error_end_position.bytes;
+    result = ts_subtree_new_error(
+      &self->tree_pool,
+      first_error_character,
+      padding,
+      size,
+      lookahead_bytes,
+      parse_state,
+      self->language
+    );
+  } else {
+    bool is_keyword = false;
+    TSSymbol symbol = self->lexer.data.result_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);
+    uint32_t lookahead_bytes = lookahead_end_byte - self->lexer.token_end_position.bytes;
+
+    if (found_external_token) {
+      symbol = self->language->external_scanner.symbol_map[symbol];
+    } else if (symbol == self->language->keyword_capture_token && symbol != 0) {
+      uint32_t end_byte = self->lexer.token_end_position.bytes;
+      ts_lexer_reset(&self->lexer, self->lexer.token_start_position);
+      ts_lexer_start(&self->lexer);
+
+      is_keyword = ts_parser__call_keyword_lex_fn(self, lex_mode);
+
+      if (
+        is_keyword &&
+        self->lexer.token_end_position.bytes == end_byte &&
+        ts_language_has_actions(self->language, parse_state, self->lexer.data.result_symbol)
+      ) {
+        symbol = self->lexer.data.result_symbol;
+      }
+    }
+
+    result = ts_subtree_new_leaf(
+      &self->tree_pool,
+      symbol,
+      padding,
+      size,
+      lookahead_bytes,
+      parse_state,
+      found_external_token,
+      called_get_column,
+      is_keyword,
+      self->language
+    );
+
+    if (found_external_token) {
+      MutableSubtree mut_result = ts_subtree_to_mut_unsafe(result);
+      ts_external_scanner_state_init(
+        &mut_result.ptr->external_scanner_state,
+        self->lexer.debug_buffer,
+        external_scanner_state_len
+      );
+      mut_result.ptr->has_external_scanner_state_change = external_scanner_state_changed;
+    }
+  }
+
+  LOG_LOOKAHEAD(
+    SYM_NAME(ts_subtree_symbol(result)),
+    ts_subtree_total_size(result).bytes
+  );
+  return result;
+}
+
+static Subtree ts_parser__get_cached_token(
+  TSParser *self,
+  TSStateId state,
+  size_t position,
+  Subtree last_external_token,
+  TableEntry *table_entry
+) {
+  TokenCache *cache = &self->token_cache;
+  if (
+    cache->token.ptr && cache->byte_index == position &&
+    ts_subtree_external_scanner_state_eq(cache->last_external_token, last_external_token)
+  ) {
+    ts_language_table_entry(self->language, state, ts_subtree_symbol(cache->token), table_entry);
+    if (ts_parser__can_reuse_first_leaf(self, state, cache->token, table_entry)) {
+      ts_subtree_retain(cache->token);
+      return cache->token;
+    }
+  }
+  return NULL_SUBTREE;
+}
+
+static void ts_parser__set_cached_token(
+  TSParser *self,
+  uint32_t byte_index,
+  Subtree last_external_token,
+  Subtree token
+) {
+  TokenCache *cache = &self->token_cache;
+  if (token.ptr) ts_subtree_retain(token);
+  if (last_external_token.ptr) ts_subtree_retain(last_external_token);
+  if (cache->token.ptr) ts_subtree_release(&self->tree_pool, cache->token);
+  if (cache->last_external_token.ptr) ts_subtree_release(&self->tree_pool, cache->last_external_token);
+  cache->token = token;
+  cache->byte_index = byte_index;
+  cache->last_external_token = last_external_token;
+}
+
+static bool ts_parser__has_included_range_difference(
+  const TSParser *self,
+  uint32_t start_position,
+  uint32_t end_position
+) {
+  return ts_range_array_intersects(
+    &self->included_range_differences,
+    self->included_range_difference_index,
+    start_position,
+    end_position
+  );
+}
+
+static Subtree ts_parser__reuse_node(
+  TSParser *self,
+  StackVersion version,
+  TSStateId *state,
+  uint32_t position,
+  Subtree last_external_token,
+  TableEntry *table_entry
+) {
+  Subtree result;
+  while ((result = reusable_node_tree(&self->reusable_node)).ptr) {
+    uint32_t byte_offset = reusable_node_byte_offset(&self->reusable_node);
+    uint32_t end_byte_offset = byte_offset + ts_subtree_total_bytes(result);
+
+    // Do not reuse an EOF node if the included ranges array has changes
+    // later on in the file.
+    if (ts_subtree_is_eof(result)) end_byte_offset = UINT32_MAX;
+
+    if (byte_offset > position) {
+      LOG("before_reusable_node symbol:%s", TREE_NAME(result));
+      break;
+    }
+
+    if (byte_offset < position) {
+      LOG("past_reusable_node symbol:%s", TREE_NAME(result));
+      if (end_byte_offset <= position || !reusable_node_descend(&self->reusable_node)) {
+        reusable_node_advance(&self->reusable_node);
+      }
+      continue;
+    }
+
+    if (!ts_subtree_external_scanner_state_eq(self->reusable_node.last_external_token, last_external_token)) {
+      LOG("reusable_node_has_different_external_scanner_state symbol:%s", TREE_NAME(result));
+      reusable_node_advance(&self->reusable_node);
+      continue;
+    }
+
+    const char *reason = NULL;
+    if (ts_subtree_has_changes(result)) {
+      reason = "has_changes";
+    } else if (ts_subtree_is_error(result)) {
+      reason = "is_error";
+    } else if (ts_subtree_missing(result)) {
+      reason = "is_missing";
+    } else if (ts_subtree_is_fragile(result)) {
+      reason = "is_fragile";
+    } else if (ts_parser__has_included_range_difference(self, byte_offset, end_byte_offset)) {
+      reason = "contains_different_included_range";
+    }
+
+    if (reason) {
+      LOG("cant_reuse_node_%s tree:%s", reason, TREE_NAME(result));
+      if (!reusable_node_descend(&self->reusable_node)) {
+        reusable_node_advance(&self->reusable_node);
+        ts_parser__breakdown_top_of_stack(self, version);
+        *state = ts_stack_state(self->stack, version);
+      }
+      continue;
+    }
+
+    TSSymbol leaf_symbol = ts_subtree_leaf_symbol(result);
+    ts_language_table_entry(self->language, *state, leaf_symbol, table_entry);
+    if (!ts_parser__can_reuse_first_leaf(self, *state, result, table_entry)) {
+      LOG(
+        "cant_reuse_node symbol:%s, first_leaf_symbol:%s",
+        TREE_NAME(result),
+        SYM_NAME(leaf_symbol)
+      );
+      reusable_node_advance_past_leaf(&self->reusable_node);
+      break;
+    }
+
+    LOG("reuse_node symbol:%s", TREE_NAME(result));
+    ts_subtree_retain(result);
+    return result;
+  }
+
+  return NULL_SUBTREE;
+}
+
+// Determine if a given tree should be replaced by an alternative tree.
+//
+// The decision is based on the trees' error costs (if any), their dynamic precedence,
+// and finally, as a default, by a recursive comparison of the trees' symbols.
+static bool ts_parser__select_tree(TSParser *self, Subtree left, Subtree right) {
+  if (!left.ptr) return true;
+  if (!right.ptr) return false;
+
+  if (ts_subtree_error_cost(right) < ts_subtree_error_cost(left)) {
+    LOG("select_smaller_error symbol:%s, over_symbol:%s", TREE_NAME(right), TREE_NAME(left));
+    return true;
+  }
+
+  if (ts_subtree_error_cost(left) < ts_subtree_error_cost(right)) {
+    LOG("select_smaller_error symbol:%s, over_symbol:%s", TREE_NAME(left), TREE_NAME(right));
+    return false;
+  }
+
+  if (ts_subtree_dynamic_precedence(right) > ts_subtree_dynamic_precedence(left)) {
+    LOG("select_higher_precedence symbol:%s, prec:%" PRId32 ", over_symbol:%s, other_prec:%" PRId32,
+        TREE_NAME(right), ts_subtree_dynamic_precedence(right), TREE_NAME(left),
+        ts_subtree_dynamic_precedence(left));
+    return true;
+  }
+
+  if (ts_subtree_dynamic_precedence(left) > ts_subtree_dynamic_precedence(right)) {
+    LOG("select_higher_precedence symbol:%s, prec:%" PRId32 ", over_symbol:%s, other_prec:%" PRId32,
+        TREE_NAME(left), ts_subtree_dynamic_precedence(left), TREE_NAME(right),
+        ts_subtree_dynamic_precedence(right));
+    return false;
+  }
+
+  if (ts_subtree_error_cost(left) > 0) return true;
+
+  int comparison = ts_subtree_compare(left, right, &self->tree_pool);
+  switch (comparison) {
+    case -1:
+      LOG("select_earlier symbol:%s, over_symbol:%s", TREE_NAME(left), TREE_NAME(right));
+      return false;
+      break;
+    case 1:
+      LOG("select_earlier symbol:%s, over_symbol:%s", TREE_NAME(right), TREE_NAME(left));
+      return true;
+    default:
+      LOG("select_existing symbol:%s, over_symbol:%s", TREE_NAME(left), TREE_NAME(right));
+      return false;
+  }
+}
+
+// Determine if a given tree's children should be replaced by an alternative
+// array of children.
+static bool ts_parser__select_children(
+  TSParser *self,
+  Subtree left,
+  const SubtreeArray *children
+) {
+  array_assign(&self->scratch_trees, children);
+
+  // Create a temporary subtree using the scratch trees array. This node does
+  // not perform any allocation except for possibly growing the array to make
+  // room for its own heap data. The scratch tree is never explicitly released,
+  // so the same 'scratch trees' array can be reused again later.
+  MutableSubtree scratch_tree = ts_subtree_new_node(
+    ts_subtree_symbol(left),
+    &self->scratch_trees,
+    0,
+    self->language
+  );
+
+  return ts_parser__select_tree(
+    self,
+    left,
+    ts_subtree_from_mut(scratch_tree)
+  );
+}
+
+static void ts_parser__shift(
+  TSParser *self,
+  StackVersion version,
+  TSStateId state,
+  Subtree lookahead,
+  bool extra
+) {
+  bool is_leaf = ts_subtree_child_count(lookahead) == 0;
+  Subtree subtree_to_push = lookahead;
+  if (extra != ts_subtree_extra(lookahead) && is_leaf) {
+    MutableSubtree result = ts_subtree_make_mut(&self->tree_pool, lookahead);
+    ts_subtree_set_extra(&result, extra);
+    subtree_to_push = ts_subtree_from_mut(result);
+  }
+
+  ts_stack_push(self->stack, version, subtree_to_push, !is_leaf, state);
+  if (ts_subtree_has_external_tokens(subtree_to_push)) {
+    ts_stack_set_last_external_token(
+      self->stack, version, ts_subtree_last_external_token(subtree_to_push)
+    );
+  }
+}
+
+static StackVersion ts_parser__reduce(
+  TSParser *self,
+  StackVersion version,
+  TSSymbol symbol,
+  uint32_t count,
+  int dynamic_precedence,
+  uint16_t production_id,
+  bool is_fragile,
+  bool end_of_non_terminal_extra
+) {
+  uint32_t initial_version_count = ts_stack_version_count(self->stack);
+
+  // Pop the given number of nodes from the given version of the parse stack.
+  // If stack versions have previously merged, then there may be more than one
+  // path back through the stack. For each path, create a new parent node to
+  // contain the popped children, and push it onto the stack in place of the
+  // children.
+  StackSliceArray pop = ts_stack_pop_count(self->stack, version, count);
+  uint32_t removed_version_count = 0;
+  for (uint32_t i = 0; i < pop.size; i++) {
+    StackSlice slice = pop.contents[i];
+    StackVersion slice_version = slice.version - removed_version_count;
+
+    // This is where new versions are added to the parse stack. The versions
+    // will all be sorted and truncated at the end of the outer parsing loop.
+    // Allow the maximum version count to be temporarily exceeded, but only
+    // by a limited threshold.
+    if (slice_version > MAX_VERSION_COUNT + MAX_VERSION_COUNT_OVERFLOW) {
+      ts_stack_remove_version(self->stack, slice_version);
+      ts_subtree_array_delete(&self->tree_pool, &slice.subtrees);
+      removed_version_count++;
+      while (i + 1 < pop.size) {
+        StackSlice next_slice = pop.contents[i + 1];
+        if (next_slice.version != slice.version) break;
+        ts_subtree_array_delete(&self->tree_pool, &next_slice.subtrees);
+        i++;
+      }
+      continue;
+    }
+
+    // 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.
+    SubtreeArray children = slice.subtrees;
+    ts_subtree_array_remove_trailing_extras(&children, &self->trailing_extras);
+
+    MutableSubtree parent = ts_subtree_new_node(
+      symbol, &children, production_id, self->language
+    );
+
+    // 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.size) {
+      StackSlice next_slice = pop.contents[i + 1];
+      if (next_slice.version != slice.version) break;
+      i++;
+
+      SubtreeArray next_slice_children = next_slice.subtrees;
+      ts_subtree_array_remove_trailing_extras(&next_slice_children, &self->trailing_extras2);
+
+      if (ts_parser__select_children(
+        self,
+        ts_subtree_from_mut(parent),
+        &next_slice_children
+      )) {
+        ts_subtree_array_clear(&self->tree_pool, &self->trailing_extras);
+        ts_subtree_release(&self->tree_pool, ts_subtree_from_mut(parent));
+        array_swap(&self->trailing_extras, &self->trailing_extras2);
+        parent = ts_subtree_new_node(
+          symbol, &next_slice_children, production_id, self->language
+        );
+      } else {
+        array_clear(&self->trailing_extras2);
+        ts_subtree_array_delete(&self->tree_pool, &next_slice.subtrees);
+      }
+    }
+
+    TSStateId state = ts_stack_state(self->stack, slice_version);
+    TSStateId next_state = ts_language_next_state(self->language, state, symbol);
+    if (end_of_non_terminal_extra && next_state == state) {
+      parent.ptr->extra = true;
+    }
+    if (is_fragile || pop.size > 1 || initial_version_count > 1) {
+      parent.ptr->fragile_left = true;
+      parent.ptr->fragile_right = true;
+      parent.ptr->parse_state = TS_TREE_STATE_NONE;
+    } else {
+      parent.ptr->parse_state = state;
+    }
+    parent.ptr->dynamic_precedence += dynamic_precedence;
+
+    // Push the parent node onto the stack, along with any extra tokens that
+    // were previously on top of the stack.
+    ts_stack_push(self->stack, slice_version, ts_subtree_from_mut(parent), false, next_state);
+    for (uint32_t j = 0; j < self->trailing_extras.size; j++) {
+      ts_stack_push(self->stack, slice_version, self->trailing_extras.contents[j], false, next_state);
+    }
+
+    for (StackVersion j = 0; j < slice_version; j++) {
+      if (j == version) continue;
+      if (ts_stack_merge(self->stack, j, slice_version)) {
+        removed_version_count++;
+        break;
+      }
+    }
+  }
+
+  // Return the first new stack version that was created.
+  return ts_stack_version_count(self->stack) > initial_version_count
+    ? initial_version_count
+    : STACK_VERSION_NONE;
+}
+
+static void ts_parser__accept(
+  TSParser *self,
+  StackVersion version,
+  Subtree lookahead
+) {
+  assert(ts_subtree_is_eof(lookahead));
+  ts_stack_push(self->stack, version, lookahead, false, 1);
+
+  StackSliceArray pop = ts_stack_pop_all(self->stack, version);
+  for (uint32_t i = 0; i < pop.size; i++) {
+    SubtreeArray trees = pop.contents[i].subtrees;
+
+    Subtree root = NULL_SUBTREE;
+    for (uint32_t j = trees.size - 1; j + 1 > 0; j--) {
+      Subtree tree = trees.contents[j];
+      if (!ts_subtree_extra(tree)) {
+        assert(!tree.data.is_inline);
+        uint32_t child_count = ts_subtree_child_count(tree);
+        const Subtree *children = ts_subtree_children(tree);
+        for (uint32_t k = 0; k < child_count; k++) {
+          ts_subtree_retain(children[k]);
+        }
+        array_splice(&trees, j, 1, child_count, children);
+        root = ts_subtree_from_mut(ts_subtree_new_node(
+          ts_subtree_symbol(tree),
+          &trees,
+          tree.ptr->production_id,
+          self->language
+        ));
+        ts_subtree_release(&self->tree_pool, tree);
+        break;
+      }
+    }
+
+    assert(root.ptr);
+    self->accept_count++;
+
+    if (self->finished_tree.ptr) {
+      if (ts_parser__select_tree(self, self->finished_tree, root)) {
+        ts_subtree_release(&self->tree_pool, self->finished_tree);
+        self->finished_tree = root;
+      } else {
+        ts_subtree_release(&self->tree_pool, root);
+      }
+    } else {
+      self->finished_tree = root;
+    }
+  }
+
+  ts_stack_remove_version(self->stack, pop.contents[0].version);
+  ts_stack_halt(self->stack, version);
+}
+
+static bool ts_parser__do_all_potential_reductions(
+  TSParser *self,
+  StackVersion starting_version,
+  TSSymbol lookahead_symbol
+) {
+  uint32_t initial_version_count = ts_stack_version_count(self->stack);
+
+  bool can_shift_lookahead_symbol = false;
+  StackVersion version = starting_version;
+  for (unsigned i = 0; true; i++) {
+    uint32_t version_count = ts_stack_version_count(self->stack);
+    if (version >= version_count) break;
+
+    bool merged = false;
+    for (StackVersion j = initial_version_count; j < version; j++) {
+      if (ts_stack_merge(self->stack, j, version)) {
+        merged = true;
+        break;
+      }
+    }
+    if (merged) continue;
+
+    TSStateId state = ts_stack_state(self->stack, version);
+    bool has_shift_action = false;
+    array_clear(&self->reduce_actions);
+
+    TSSymbol first_symbol, end_symbol;
+    if (lookahead_symbol != 0) {
+      first_symbol = lookahead_symbol;
+      end_symbol = lookahead_symbol + 1;
+    } else {
+      first_symbol = 1;
+      end_symbol = self->language->token_count;
+    }
+
+    for (TSSymbol symbol = first_symbol; symbol < end_symbol; symbol++) {
+      TableEntry entry;
+      ts_language_table_entry(self->language, state, symbol, &entry);
+      for (uint32_t j = 0; j < entry.action_count; j++) {
+        TSParseAction action = entry.actions[j];
+        switch (action.type) {
+          case TSParseActionTypeShift:
+          case TSParseActionTypeRecover:
+            if (!action.shift.extra && !action.shift.repetition) has_shift_action = true;
+            break;
+          case TSParseActionTypeReduce:
+            if (action.reduce.child_count > 0)
+              ts_reduce_action_set_add(&self->reduce_actions, (ReduceAction) {
+                .symbol = action.reduce.symbol,
+                .count = action.reduce.child_count,
+                .dynamic_precedence = action.reduce.dynamic_precedence,
+                .production_id = action.reduce.production_id,
+              });
+            break;
+          default:
+            break;
+        }
+      }
+    }
+
+    StackVersion reduction_version = STACK_VERSION_NONE;
+    for (uint32_t j = 0; j < self->reduce_actions.size; j++) {
+      ReduceAction action = self->reduce_actions.contents[j];
+
+      reduction_version = ts_parser__reduce(
+        self, version, action.symbol, action.count,
+        action.dynamic_precedence, action.production_id,
+        true, false
+      );
+    }
+
+    if (has_shift_action) {
+      can_shift_lookahead_symbol = true;
+    } else if (reduction_version != STACK_VERSION_NONE && i < MAX_VERSION_COUNT) {
+      ts_stack_renumber_version(self->stack, reduction_version, version);
+      continue;
+    } else if (lookahead_symbol != 0) {
+      ts_stack_remove_version(self->stack, version);
+    }
+
+    if (version == starting_version) {
+      version = version_count;
+    } else {
+      version++;
+    }
+  }
+
+  return can_shift_lookahead_symbol;
+}
+
+static bool ts_parser__recover_to_state(
+  TSParser *self,
+  StackVersion version,
+  unsigned depth,
+  TSStateId goal_state
+) {
+  StackSliceArray pop = ts_stack_pop_count(self->stack, version, depth);
+  StackVersion previous_version = STACK_VERSION_NONE;
+
+  for (unsigned i = 0; i < pop.size; i++) {
+    StackSlice slice = pop.contents[i];
+
+    if (slice.version == previous_version) {
+      ts_subtree_array_delete(&self->tree_pool, &slice.subtrees);
+      array_erase(&pop, i--);
+      continue;
+    }
+
+    if (ts_stack_state(self->stack, slice.version) != goal_state) {
+      ts_stack_halt(self->stack, slice.version);
+      ts_subtree_array_delete(&self->tree_pool, &slice.subtrees);
+      array_erase(&pop, i--);
+      continue;
+    }
+
+    SubtreeArray error_trees = ts_stack_pop_error(self->stack, slice.version);
+    if (error_trees.size > 0) {
+      assert(error_trees.size == 1);
+      Subtree error_tree = error_trees.contents[0];
+      uint32_t error_child_count = ts_subtree_child_count(error_tree);
+      if (error_child_count > 0) {
+        array_splice(&slice.subtrees, 0, 0, error_child_count, ts_subtree_children(error_tree));
+        for (unsigned j = 0; j < error_child_count; j++) {
+          ts_subtree_retain(slice.subtrees.contents[j]);
+        }
+      }
+      ts_subtree_array_delete(&self->tree_pool, &error_trees);
+    }
+
+    ts_subtree_array_remove_trailing_extras(&slice.subtrees, &self->trailing_extras);
+
+    if (slice.subtrees.size > 0) {
+      Subtree error = ts_subtree_new_error_node(&slice.subtrees, true, self->language);
+      ts_stack_push(self->stack, slice.version, error, false, goal_state);
+    } else {
+      array_delete(&slice.subtrees);
+    }
+
+    for (unsigned j = 0; j < self->trailing_extras.size; j++) {
+      Subtree tree = self->trailing_extras.contents[j];
+      ts_stack_push(self->stack, slice.version, tree, false, goal_state);
+    }
+
+    previous_version = slice.version;
+  }
+
+  return previous_version != STACK_VERSION_NONE;
+}
+
+static void ts_parser__recover(
+  TSParser *self,
+  StackVersion version,
+  Subtree lookahead
+) {
+  bool did_recover = false;
+  unsigned previous_version_count = ts_stack_version_count(self->stack);
+  Length position = ts_stack_position(self->stack, version);
+  StackSummary *summary = ts_stack_get_summary(self->stack, version);
+  unsigned node_count_since_error = ts_stack_node_count_since_error(self->stack, version);
+  unsigned current_error_cost = ts_stack_error_cost(self->stack, version);
+
+  // When the parser is in the error state, there are two strategies for recovering with a
+  // given lookahead token:
+  // 1. Find a previous state on the stack in which that lookahead token would be valid. Then,
+  //    create a new stack version that is in that state again. This entails popping all of the
+  //    subtrees that have been pushed onto the stack since that previous state, and wrapping
+  //    them in an ERROR node.
+  // 2. Wrap the lookahead token in an ERROR node, push that ERROR node onto the stack, and
+  //    move on to the next lookahead token, remaining in the error state.
+  //
+  // First, try the strategy 1. Upon entering the error state, the parser recorded a summary
+  // of the previous parse states and their depths. Look at each state in the summary, to see
+  // if the current lookahead token would be valid in that state.
+  if (summary && !ts_subtree_is_error(lookahead)) {
+    for (unsigned i = 0; i < summary->size; i++) {
+      StackSummaryEntry entry = summary->contents[i];
+
+      if (entry.state == ERROR_STATE) continue;
+      if (entry.position.bytes == position.bytes) continue;
+      unsigned depth = entry.depth;
+      if (node_count_since_error > 0) depth++;
+
+      // Do not recover in ways that create redundant stack versions.
+      bool would_merge = false;
+      for (unsigned j = 0; j < previous_version_count; j++) {
+        if (
+          ts_stack_state(self->stack, j) == entry.state &&
+          ts_stack_position(self->stack, j).bytes == position.bytes
+        ) {
+          would_merge = true;
+          break;
+        }
+      }
+      if (would_merge) continue;
+
+      // Do not recover if the result would clearly be worse than some existing stack version.
+      unsigned new_cost =
+        current_error_cost +
+        entry.depth * ERROR_COST_PER_SKIPPED_TREE +
+        (position.bytes - entry.position.bytes) * ERROR_COST_PER_SKIPPED_CHAR +
+        (position.extent.row - entry.position.extent.row) * ERROR_COST_PER_SKIPPED_LINE;
+      if (ts_parser__better_version_exists(self, version, false, new_cost)) break;
+
+      // If the current lookahead token is valid in some previous state, recover to that state.
+      // Then stop looking for further recoveries.
+      if (ts_language_has_actions(self->language, entry.state, ts_subtree_symbol(lookahead))) {
+        if (ts_parser__recover_to_state(self, version, depth, entry.state)) {
+          did_recover = true;
+          LOG("recover_to_previous state:%u, depth:%u", entry.state, depth);
+          LOG_STACK();
+          break;
+        }
+      }
+    }
+  }
+
+  // In the process of attempting to recover, some stack versions may have been created
+  // and subsequently halted. Remove those versions.
+  for (unsigned i = previous_version_count; i < ts_stack_version_count(self->stack); i++) {
+    if (!ts_stack_is_active(self->stack, i)) {
+      ts_stack_remove_version(self->stack, i--);
+    }
+  }
+
+  // If strategy 1 succeeded, a new stack version will have been created which is able to handle
+  // the current lookahead token. Now, in addition, try strategy 2 described above: skip the
+  // current lookahead token by wrapping it in an ERROR node.
+
+  // Don't pursue this additional strategy if there are already too many stack versions.
+  if (did_recover && ts_stack_version_count(self->stack) > MAX_VERSION_COUNT) {
+    ts_stack_halt(self->stack, version);
+    ts_subtree_release(&self->tree_pool, lookahead);
+    return;
+  }
+
+  if (
+    did_recover &&
+    ts_subtree_has_external_scanner_state_change(lookahead)
+  ) {
+    ts_stack_halt(self->stack, version);
+    ts_subtree_release(&self->tree_pool, lookahead);
+    return;
+  }
+
+  // If the parser is still in the error state at the end of the file, just wrap everything
+  // in an ERROR node and terminate.
+  if (ts_subtree_is_eof(lookahead)) {
+    LOG("recover_eof");
+    SubtreeArray children = array_new();
+    Subtree parent = ts_subtree_new_error_node(&children, false, self->language);
+    ts_stack_push(self->stack, version, parent, false, 1);
+    ts_parser__accept(self, version, lookahead);
+    return;
+  }
+
+  // Do not recover if the result would clearly be worse than some existing stack version.
+  unsigned new_cost =
+    current_error_cost + ERROR_COST_PER_SKIPPED_TREE +
+    ts_subtree_total_bytes(lookahead) * ERROR_COST_PER_SKIPPED_CHAR +
+    ts_subtree_total_size(lookahead).extent.row * ERROR_COST_PER_SKIPPED_LINE;
+  if (ts_parser__better_version_exists(self, version, false, new_cost)) {
+    ts_stack_halt(self->stack, version);
+    ts_subtree_release(&self->tree_pool, lookahead);
+    return;
+  }
+
+  // If the current lookahead token is an extra token, mark it as extra. This means it won't
+  // be counted in error cost calculations.
+  unsigned n;
+  const TSParseAction *actions = ts_language_actions(self->language, 1, ts_subtree_symbol(lookahead), &n);
+  if (n > 0 && actions[n - 1].type == TSParseActionTypeShift && actions[n - 1].shift.extra) {
+    MutableSubtree mutable_lookahead = ts_subtree_make_mut(&self->tree_pool, lookahead);
+    ts_subtree_set_extra(&mutable_lookahead, true);
+    lookahead = ts_subtree_from_mut(mutable_lookahead);
+  }
+
+  // Wrap the lookahead token in an ERROR.
+  LOG("skip_token symbol:%s", TREE_NAME(lookahead));
+  SubtreeArray children = array_new();
+  array_reserve(&children, 1);
+  array_push(&children, lookahead);
+  MutableSubtree error_repeat = ts_subtree_new_node(
+    ts_builtin_sym_error_repeat,
+    &children,
+    0,
+    self->language
+  );
+
+  // If other tokens have already been skipped, so there is already an ERROR at the top of the
+  // stack, then pop that ERROR off the stack and wrap the two ERRORs together into one larger
+  // ERROR.
+  if (node_count_since_error > 0) {
+    StackSliceArray pop = ts_stack_pop_count(self->stack, version, 1);
+
+    // TODO: Figure out how to make this condition occur.
+    // See https://github.com/atom/atom/issues/18450#issuecomment-439579778
+    // If multiple stack versions have merged at this point, just pick one of the errors
+    // arbitrarily and discard the rest.
+    if (pop.size > 1) {
+      for (unsigned i = 1; i < pop.size; i++) {
+        ts_subtree_array_delete(&self->tree_pool, &pop.contents[i].subtrees);
+      }
+      while (ts_stack_version_count(self->stack) > pop.contents[0].version + 1) {
+        ts_stack_remove_version(self->stack, pop.contents[0].version + 1);
+      }
+    }
+
+    ts_stack_renumber_version(self->stack, pop.contents[0].version, version);
+    array_push(&pop.contents[0].subtrees, ts_subtree_from_mut(error_repeat));
+    error_repeat = ts_subtree_new_node(
+      ts_builtin_sym_error_repeat,
+      &pop.contents[0].subtrees,
+      0,
+      self->language
+    );
+  }
+
+  // Push the new ERROR onto the stack.
+  ts_stack_push(self->stack, version, ts_subtree_from_mut(error_repeat), false, ERROR_STATE);
+  if (ts_subtree_has_external_tokens(lookahead)) {
+    ts_stack_set_last_external_token(
+      self->stack, version, ts_subtree_last_external_token(lookahead)
+    );
+  }
+}
+
+static void ts_parser__handle_error(
+  TSParser *self,
+  StackVersion version,
+  Subtree lookahead
+) {
+  uint32_t previous_version_count = ts_stack_version_count(self->stack);
+
+  // Perform any reductions that can happen in this state, regardless of the lookahead. After
+  // skipping one or more invalid tokens, the parser might find a token that would have allowed
+  // a reduction to take place.
+  ts_parser__do_all_potential_reductions(self, version, 0);
+  uint32_t version_count = ts_stack_version_count(self->stack);
+  Length position = ts_stack_position(self->stack, version);
+
+  // Push a discontinuity onto the stack. Merge all of the stack versions that
+  // were created in the previous step.
+  bool did_insert_missing_token = false;
+  for (StackVersion v = version; v < version_count;) {
+    if (!did_insert_missing_token) {
+      TSStateId state = ts_stack_state(self->stack, v);
+      for (
+        TSSymbol missing_symbol = 1;
+        missing_symbol < (uint16_t)self->language->token_count;
+        missing_symbol++
+      ) {
+        TSStateId state_after_missing_symbol = ts_language_next_state(
+          self->language, state, missing_symbol
+        );
+        if (state_after_missing_symbol == 0 || state_after_missing_symbol == state) {
+          continue;
+        }
+
+        if (ts_language_has_reduce_action(
+          self->language,
+          state_after_missing_symbol,
+          ts_subtree_leaf_symbol(lookahead)
+        )) {
+          // In case the parser is currently outside of any included range, the lexer will
+          // snap to the beginning of the next included range. The missing token's padding
+          // must be assigned to position it within the next included range.
+          ts_lexer_reset(&self->lexer, position);
+          ts_lexer_mark_end(&self->lexer);
+          Length padding = length_sub(self->lexer.token_end_position, position);
+          uint32_t lookahead_bytes = ts_subtree_total_bytes(lookahead) + ts_subtree_lookahead_bytes(lookahead);
+
+          StackVersion version_with_missing_tree = ts_stack_copy_version(self->stack, v);
+          Subtree missing_tree = ts_subtree_new_missing_leaf(
+            &self->tree_pool, missing_symbol,
+            padding, lookahead_bytes,
+            self->language
+          );
+          ts_stack_push(
+            self->stack, version_with_missing_tree,
+            missing_tree, false,
+            state_after_missing_symbol
+          );
+
+          if (ts_parser__do_all_potential_reductions(
+            self, version_with_missing_tree,
+            ts_subtree_leaf_symbol(lookahead)
+          )) {
+            LOG(
+              "recover_with_missing symbol:%s, state:%u",
+              SYM_NAME(missing_symbol),
+              ts_stack_state(self->stack, version_with_missing_tree)
+            );
+            did_insert_missing_token = true;
+            break;
+          }
+        }
+      }
+    }
+
+    ts_stack_push(self->stack, v, NULL_SUBTREE, false, ERROR_STATE);
+    v = (v == version) ? previous_version_count : v + 1;
+  }
+
+  for (unsigned i = previous_version_count; i < version_count; i++) {
+    bool did_merge = ts_stack_merge(self->stack, version, previous_version_count);
+    assert(did_merge);
+    (void)did_merge;    //      fix warning/error with clang -Os
+  }
+
+  ts_stack_record_summary(self->stack, version, MAX_SUMMARY_DEPTH);
+
+  // Begin recovery with the current lookahead node, rather than waiting for the
+  // next turn of the parse loop. This ensures that the tree accounts for the
+  // current lookahead token's "lookahead bytes" value, which describes how far
+  // the lexer needed to look ahead beyond the content of the token in order to
+  // recognize it.
+  if (ts_subtree_child_count(lookahead) > 0) {
+    ts_parser__breakdown_lookahead(self, &lookahead, ERROR_STATE, &self->reusable_node);
+  }
+  ts_parser__recover(self, version, lookahead);
+
+  LOG_STACK();
+}
+
+static bool ts_parser__advance(
+  TSParser *self,
+  StackVersion version,
+  bool allow_node_reuse
+) {
+  TSStateId state = ts_stack_state(self->stack, version);
+  uint32_t position = ts_stack_position(self->stack, version).bytes;
+  Subtree last_external_token = ts_stack_last_external_token(self->stack, version);
+
+  bool did_reuse = true;
+  Subtree lookahead = NULL_SUBTREE;
+  TableEntry table_entry = {.action_count = 0};
+
+  // If possible, reuse a node from the previous syntax tree.
+  if (allow_node_reuse) {
+    lookahead = ts_parser__reuse_node(
+      self, version, &state, position, last_external_token, &table_entry
+    );
+  }
+
+  // If no node from the previous syntax tree could be reused, then try to
+  // reuse the token previously returned by the lexer.
+  if (!lookahead.ptr) {
+    did_reuse = false;
+    lookahead = ts_parser__get_cached_token(
+      self, state, position, last_external_token, &table_entry
+    );
+  }
+
+  bool needs_lex = !lookahead.ptr;
+  for (;;) {
+    // Otherwise, re-run the lexer.
+    if (needs_lex) {
+      needs_lex = false;
+      lookahead = ts_parser__lex(self, version, state);
+      if (self->has_scanner_error) return false;
+
+      if (lookahead.ptr) {
+        ts_parser__set_cached_token(self, position, last_external_token, lookahead);
+        ts_language_table_entry(self->language, state, ts_subtree_symbol(lookahead), &table_entry);
+      }
+
+      // When parsing a non-terminal extra, a null lookahead indicates the
+      // end of the rule. The reduction is stored in the EOF table entry.
+      // After the reduction, the lexer needs to be run again.
+      else {
+        ts_language_table_entry(self->language, state, ts_builtin_sym_end, &table_entry);
+      }
+    }
+
+    // If a cancellation flag or a timeout was provided, then check every
+    // time a fixed number of parse actions has been processed.
+    if (++self->operation_count == OP_COUNT_PER_TIMEOUT_CHECK) {
+      self->operation_count = 0;
+    }
+    if (
+      self->operation_count == 0 &&
+      ((self->cancellation_flag && atomic_load(self->cancellation_flag)) ||
+       (!clock_is_null(self->end_clock) && clock_is_gt(clock_now(), self->end_clock)))
+    ) {
+      if (lookahead.ptr) {
+        ts_subtree_release(&self->tree_pool, lookahead);
+      }
+      return false;
+    }
+
+    // Process each parse action for the current lookahead token in
+    // the current state. If there are multiple actions, then this is
+    // an ambiguous state. REDUCE actions always create a new stack
+    // version, whereas SHIFT actions update the existing stack version
+    // and terminate this loop.
+    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: {
+          if (action.shift.repetition) break;
+          TSStateId next_state;
+          if (action.shift.extra) {
+            next_state = state;
+            LOG("shift_extra");
+          } else {
+            next_state = action.shift.state;
+            LOG("shift state:%u", next_state);
+          }
+
+          if (ts_subtree_child_count(lookahead) > 0) {
+            ts_parser__breakdown_lookahead(self, &lookahead, state, &self->reusable_node);
+            next_state = ts_language_next_state(self->language, state, ts_subtree_symbol(lookahead));
+          }
+
+          ts_parser__shift(self, version, next_state, lookahead, action.shift.extra);
+          if (did_reuse) reusable_node_advance(&self->reusable_node);
+          return true;
+        }
+
+        case TSParseActionTypeReduce: {
+          bool is_fragile = table_entry.action_count > 1;
+          bool end_of_non_terminal_extra = lookahead.ptr == NULL;
+          LOG("reduce sym:%s, child_count:%u", SYM_NAME(action.reduce.symbol), action.reduce.child_count);
+          StackVersion reduction_version = ts_parser__reduce(
+            self, version, action.reduce.symbol, action.reduce.child_count,
+            action.reduce.dynamic_precedence, action.reduce.production_id,
+            is_fragile, end_of_non_terminal_extra
+          );
+          if (reduction_version != STACK_VERSION_NONE) {
+            last_reduction_version = reduction_version;
+          }
+          break;
+        }
+
+        case TSParseActionTypeAccept: {
+          LOG("accept");
+          ts_parser__accept(self, version, lookahead);
+          return true;
+        }
+
+        case TSParseActionTypeRecover: {
+          if (ts_subtree_child_count(lookahead) > 0) {
+            ts_parser__breakdown_lookahead(self, &lookahead, ERROR_STATE, &self->reusable_node);
+          }
+
+          ts_parser__recover(self, version, lookahead);
+          if (did_reuse) reusable_node_advance(&self->reusable_node);
+          return true;
+        }
+      }
+    }
+
+    // If a reduction was performed, then replace the current stack version
+    // with one of the stack versions created by a reduction, and continue
+    // processing this version of the stack with the same lookahead symbol.
+    if (last_reduction_version != STACK_VERSION_NONE) {
+      ts_stack_renumber_version(self->stack, last_reduction_version, version);
+      LOG_STACK();
+      state = ts_stack_state(self->stack, version);
+
+      // At the end of a non-terminal extra rule, the lexer will return a
+      // null subtree, because the parser needs to perform a fixed reduction
+      // regardless of the lookahead node. After performing that reduction,
+      // (and completing the non-terminal extra rule) run the lexer again based
+      // on the current parse state.
+      if (!lookahead.ptr) {
+        needs_lex = true;
+      } else {
+        ts_language_table_entry(
+          self->language,
+          state,
+          ts_subtree_leaf_symbol(lookahead),
+          &table_entry
+        );
+      }
+
+      continue;
+    }
+
+    // A non-terminal extra rule was reduced and merged into an existing
+    // stack version. This version can be discarded.
+    if (!lookahead.ptr) {
+      ts_stack_halt(self->stack, version);
+      return true;
+    }
+
+    // If there were no parse actions for the current lookahead token, then
+    // it is not valid in this state. If the current lookahead token is a
+    // keyword, then switch to treating it as the normal word token if that
+    // token is valid in this state.
+    if (
+      ts_subtree_is_keyword(lookahead) &&
+      ts_subtree_symbol(lookahead) != self->language->keyword_capture_token
+    ) {
+      ts_language_table_entry(self->language, state, self->language->keyword_capture_token, &table_entry);
+      if (table_entry.action_count > 0) {
+        LOG(
+          "switch from_keyword:%s, to_word_token:%s",
+          TREE_NAME(lookahead),
+          SYM_NAME(self->language->keyword_capture_token)
+        );
+
+        MutableSubtree mutable_lookahead = ts_subtree_make_mut(&self->tree_pool, lookahead);
+        ts_subtree_set_symbol(&mutable_lookahead, self->language->keyword_capture_token, self->language);
+        lookahead = ts_subtree_from_mut(mutable_lookahead);
+        continue;
+      }
+    }
+
+    // If the current lookahead token is not valid and the parser is
+    // already in the error state, restart the error recovery process.
+    // TODO - can this be unified with the other `RECOVER` case above?
+    if (state == ERROR_STATE) {
+      ts_parser__recover(self, version, lookahead);
+      return true;
+    }
+
+    // If the current lookahead token is not valid and the previous
+    // subtree on the stack was reused from an old tree, it isn't actually
+    // valid to reuse it. Remove it from the stack, and in its place,
+    // push each of its children. Then try again to process the current
+    // lookahead.
+    if (ts_parser__breakdown_top_of_stack(self, version)) {
+      state = ts_stack_state(self->stack, version);
+      ts_subtree_release(&self->tree_pool, lookahead);
+      needs_lex = true;
+      continue;
+    }
+
+    // At this point, the current lookahead token is definitely not valid
+    // for this parse stack version. Mark this version as paused and continue
+    // processing any other stack versions that might exist. If some other
+    // version advances successfully, then this version can simply be removed.
+    // But if all versions end up paused, then error recovery is needed.
+    LOG("detect_error");
+    ts_stack_pause(self->stack, version, lookahead);
+    return true;
+  }
+}
+
+static unsigned ts_parser__condense_stack(TSParser *self) {
+  bool made_changes = false;
+  unsigned min_error_cost = UINT_MAX;
+  for (StackVersion i = 0; i < ts_stack_version_count(self->stack); i++) {
+    // Prune any versions that have been marked for removal.
+    if (ts_stack_is_halted(self->stack, i)) {
+      ts_stack_remove_version(self->stack, i);
+      i--;
+      continue;
+    }
+
+    // Keep track of the minimum error cost of any stack version so
+    // that it can be returned.
+    ErrorStatus status_i = ts_parser__version_status(self, i);
+    if (!status_i.is_in_error && status_i.cost < min_error_cost) {
+      min_error_cost = status_i.cost;
+    }
+
+    // Examine each pair of stack versions, removing any versions that
+    // are clearly worse than another version. Ensure that the versions
+    // are ordered from most promising to least promising.
+    for (StackVersion j = 0; j < i; j++) {
+      ErrorStatus status_j = ts_parser__version_status(self, j);
+
+      switch (ts_parser__compare_versions(self, status_j, status_i)) {
+        case ErrorComparisonTakeLeft:
+          made_changes = true;
+          ts_stack_remove_version(self->stack, i);
+          i--;
+          j = i;
+          break;
+
+        case ErrorComparisonPreferLeft:
+        case ErrorComparisonNone:
+          if (ts_stack_merge(self->stack, j, i)) {
+            made_changes = true;
+            i--;
+            j = i;
+          }
+          break;
+
+        case ErrorComparisonPreferRight:
+          made_changes = true;
+          if (ts_stack_merge(self->stack, j, i)) {
+            i--;
+            j = i;
+          } else {
+            ts_stack_swap_versions(self->stack, i, j);
+          }
+          break;
+
+        case ErrorComparisonTakeRight:
+          made_changes = true;
+          ts_stack_remove_version(self->stack, j);
+          i--;
+          j--;
+          break;
+      }
+    }
+  }
+
+  // Enforce a hard upper bound on the number of stack versions by
+  // discarding the least promising versions.
+  while (ts_stack_version_count(self->stack) > MAX_VERSION_COUNT) {
+    ts_stack_remove_version(self->stack, MAX_VERSION_COUNT);
+    made_changes = true;
+  }
+
+  // If the best-performing stack version is currently paused, or all
+  // versions are paused, then resume the best paused version and begin
+  // the error recovery process. Otherwise, remove the paused versions.
+  if (ts_stack_version_count(self->stack) > 0) {
+    bool has_unpaused_version = false;
+    for (StackVersion i = 0, n = ts_stack_version_count(self->stack); i < n; i++) {
+      if (ts_stack_is_paused(self->stack, i)) {
+        if (!has_unpaused_version && self->accept_count < MAX_VERSION_COUNT) {
+          LOG("resume version:%u", i);
+          min_error_cost = ts_stack_error_cost(self->stack, i);
+          Subtree lookahead = ts_stack_resume(self->stack, i);
+          ts_parser__handle_error(self, i, lookahead);
+          has_unpaused_version = true;
+        } else {
+          ts_stack_remove_version(self->stack, i);
+          i--;
+          n--;
+        }
+      } else {
+        has_unpaused_version = true;
+      }
+    }
+  }
+
+  if (made_changes) {
+    LOG("condense");
+    LOG_STACK();
+  }
+
+  return min_error_cost;
+}
+
+static bool ts_parser_has_outstanding_parse(TSParser *self) {
+  return (
+    self->external_scanner_payload ||
+    ts_stack_state(self->stack, 0) != 1 ||
+    ts_stack_node_count_since_error(self->stack, 0) != 0
+  );
+}
+
+// Parser - Public
+
+TSParser *ts_parser_new(void) {
+  TSParser *self = ts_calloc(1, sizeof(TSParser));
+  ts_lexer_init(&self->lexer);
+  array_init(&self->reduce_actions);
+  array_reserve(&self->reduce_actions, 4);
+  self->tree_pool = ts_subtree_pool_new(32);
+  self->stack = ts_stack_new(&self->tree_pool);
+  self->finished_tree = NULL_SUBTREE;
+  self->reusable_node = reusable_node_new();
+  self->dot_graph_file = NULL;
+  self->cancellation_flag = NULL;
+  self->timeout_duration = 0;
+  self->language = NULL;
+  self->has_scanner_error = false;
+  self->external_scanner_payload = NULL;
+  self->end_clock = clock_null();
+  self->operation_count = 0;
+  self->old_tree = NULL_SUBTREE;
+  self->included_range_differences = (TSRangeArray) array_new();
+  self->included_range_difference_index = 0;
+  ts_parser__set_cached_token(self, 0, NULL_SUBTREE, NULL_SUBTREE);
+  return self;
+}
+
+void ts_parser_delete(TSParser *self) {
+  if (!self) return;
+
+  ts_parser_set_language(self, NULL);
+  ts_stack_delete(self->stack);
+  if (self->reduce_actions.contents) {
+    array_delete(&self->reduce_actions);
+  }
+  if (self->included_range_differences.contents) {
+    array_delete(&self->included_range_differences);
+  }
+  if (self->old_tree.ptr) {
+    ts_subtree_release(&self->tree_pool, self->old_tree);
+    self->old_tree = NULL_SUBTREE;
+  }
+  ts_wasm_store_delete(self->wasm_store);
+  ts_lexer_delete(&self->lexer);
+  ts_parser__set_cached_token(self, 0, NULL_SUBTREE, NULL_SUBTREE);
+  ts_subtree_pool_delete(&self->tree_pool);
+  reusable_node_delete(&self->reusable_node);
+  array_delete(&self->trailing_extras);
+  array_delete(&self->trailing_extras2);
+  array_delete(&self->scratch_trees);
+  ts_free(self);
+}
+
+const TSLanguage *ts_parser_language(const TSParser *self) {
+  return self->language;
+}
+
+bool ts_parser_set_language(TSParser *self, const TSLanguage *language) {
+  ts_parser_reset(self);
+  ts_language_delete(self->language);
+  self->language = NULL;
+
+  if (language) {
+    if (
+      language->version > TREE_SITTER_LANGUAGE_VERSION ||
+      language->version < TREE_SITTER_MIN_COMPATIBLE_LANGUAGE_VERSION
+    ) return false;
+
+    if (ts_language_is_wasm(language)) {
+      if (
+        !self->wasm_store ||
+        !ts_wasm_store_start(self->wasm_store, &self->lexer.data, language)
+      ) return false;
+    }
+  }
+
+  self->language = ts_language_copy(language);
+  return true;
+}
+
+TSLogger ts_parser_logger(const TSParser *self) {
+  return self->lexer.logger;
+}
+
+void ts_parser_set_logger(TSParser *self, TSLogger logger) {
+  self->lexer.logger = logger;
+}
+
+void ts_parser_print_dot_graphs(TSParser *self, int fd) {
+  if (self->dot_graph_file) {
+    fclose(self->dot_graph_file);
+  }
+
+  if (fd >= 0) {
+    #ifdef _WIN32
+    self->dot_graph_file = _fdopen(fd, "a");
+    #else
+    self->dot_graph_file = fdopen(fd, "a");
+    #endif
+  } else {
+    self->dot_graph_file = NULL;
+  }
+}
+
+const size_t *ts_parser_cancellation_flag(const TSParser *self) {
+  return (const size_t *)self->cancellation_flag;
+}
+
+void ts_parser_set_cancellation_flag(TSParser *self, const size_t *flag) {
+  self->cancellation_flag = (const volatile size_t *)flag;
+}
+
+uint64_t ts_parser_timeout_micros(const TSParser *self) {
+  return duration_to_micros(self->timeout_duration);
+}
+
+void ts_parser_set_timeout_micros(TSParser *self, uint64_t timeout_micros) {
+  self->timeout_duration = duration_from_micros(timeout_micros);
+}
+
+bool ts_parser_set_included_ranges(
+  TSParser *self,
+  const TSRange *ranges,
+  uint32_t count
+) {
+  return ts_lexer_set_included_ranges(&self->lexer, ranges, count);
+}
+
+const TSRange *ts_parser_included_ranges(const TSParser *self, uint32_t *count) {
+  return ts_lexer_included_ranges(&self->lexer, count);
+}
+
+void ts_parser_reset(TSParser *self) {
+  ts_parser__external_scanner_destroy(self);
+  if (self->wasm_store) {
+    ts_wasm_store_reset(self->wasm_store);
+  }
+
+  if (self->old_tree.ptr) {
+    ts_subtree_release(&self->tree_pool, self->old_tree);
+    self->old_tree = NULL_SUBTREE;
+  }
+
+  reusable_node_clear(&self->reusable_node);
+  ts_lexer_reset(&self->lexer, length_zero());
+  ts_stack_clear(self->stack);
+  ts_parser__set_cached_token(self, 0, NULL_SUBTREE, NULL_SUBTREE);
+  if (self->finished_tree.ptr) {
+    ts_subtree_release(&self->tree_pool, self->finished_tree);
+    self->finished_tree = NULL_SUBTREE;
+  }
+  self->accept_count = 0;
+  self->has_scanner_error = false;
+}
+
+TSTree *ts_parser_parse(
+  TSParser *self,
+  const TSTree *old_tree,
+  TSInput input
+) {
+  TSTree *result = NULL;
+  if (!self->language || !input.read) return NULL;
+
+  if (ts_language_is_wasm(self->language)) {
+    if (!self->wasm_store) return NULL;
+    ts_wasm_store_start(self->wasm_store, &self->lexer.data, self->language);
+  }
+
+  ts_lexer_set_input(&self->lexer, input);
+  array_clear(&self->included_range_differences);
+  self->included_range_difference_index = 0;
+
+  if (ts_parser_has_outstanding_parse(self)) {
+    LOG("resume_parsing");
+  } else {
+    ts_parser__external_scanner_create(self);
+    if (self->has_scanner_error) goto exit;
+
+    if (old_tree) {
+      ts_subtree_retain(old_tree->root);
+      self->old_tree = old_tree->root;
+      ts_range_array_get_changed_ranges(
+        old_tree->included_ranges, old_tree->included_range_count,
+        self->lexer.included_ranges, self->lexer.included_range_count,
+        &self->included_range_differences
+      );
+      reusable_node_reset(&self->reusable_node, old_tree->root);
+      LOG("parse_after_edit");
+      LOG_TREE(self->old_tree);
+      for (unsigned i = 0; i < self->included_range_differences.size; i++) {
+        TSRange *range = &self->included_range_differences.contents[i];
+        LOG("different_included_range %u - %u", range->start_byte, range->end_byte);
+      }
+    } else {
+      reusable_node_clear(&self->reusable_node);
+      LOG("new_parse");
+    }
+  }
+
+  self->operation_count = 0;
+  if (self->timeout_duration) {
+    self->end_clock = clock_after(clock_now(), self->timeout_duration);
+  } else {
+    self->end_clock = clock_null();
+  }
+
+  uint32_t position = 0, last_position = 0, version_count = 0;
+  do {
+    for (
+      StackVersion version = 0;
+      version_count = ts_stack_version_count(self->stack),
+      version < version_count;
+      version++
+    ) {
+      bool allow_node_reuse = version_count == 1;
+      while (ts_stack_is_active(self->stack, version)) {
+        LOG(
+          "process version:%u, version_count:%u, state:%d, row:%u, col:%u",
+          version,
+          ts_stack_version_count(self->stack),
+          ts_stack_state(self->stack, version),
+          ts_stack_position(self->stack, version).extent.row,
+          ts_stack_position(self->stack, version).extent.column
+        );
+
+        if (!ts_parser__advance(self, version, allow_node_reuse)) {
+          if (self->has_scanner_error) goto exit;
+          return NULL;
+        }
+
+        LOG_STACK();
+
+        position = ts_stack_position(self->stack, version).bytes;
+        if (position > last_position || (version > 0 && position == last_position)) {
+          last_position = position;
+          break;
+        }
+      }
+    }
+
+    // After advancing each version of the stack, re-sort the versions by their cost,
+    // removing any versions that are no longer worth pursuing.
+    unsigned min_error_cost = ts_parser__condense_stack(self);
+
+    // If there's already a finished parse tree that's better than any in-progress version,
+    // then terminate parsing. Clear the parse stack to remove any extra references to subtrees
+    // within the finished tree, ensuring that these subtrees can be safely mutated in-place
+    // for rebalancing.
+    if (self->finished_tree.ptr && ts_subtree_error_cost(self->finished_tree) < min_error_cost) {
+      ts_stack_clear(self->stack);
+      break;
+    }
+
+    while (self->included_range_difference_index < self->included_range_differences.size) {
+      TSRange *range = &self->included_range_differences.contents[self->included_range_difference_index];
+      if (range->end_byte <= position) {
+        self->included_range_difference_index++;
+      } else {
+        break;
+      }
+    }
+  } while (version_count != 0);
+
+  assert(self->finished_tree.ptr);
+  ts_subtree_balance(self->finished_tree, &self->tree_pool, self->language);
+  LOG("done");
+  LOG_TREE(self->finished_tree);
+
+  result = ts_tree_new(
+    self->finished_tree,
+    self->language,
+    self->lexer.included_ranges,
+    self->lexer.included_range_count
+  );
+  self->finished_tree = NULL_SUBTREE;
+
+exit:
+  ts_parser_reset(self);
+  return result;
+}
+
+TSTree *ts_parser_parse_string(
+  TSParser *self,
+  const TSTree *old_tree,
+  const char *string,
+  uint32_t length
+) {
+  return ts_parser_parse_string_encoding(self, old_tree, string, length, TSInputEncodingUTF8);
+}
+
+TSTree *ts_parser_parse_string_encoding(
+  TSParser *self,
+  const TSTree *old_tree,
+  const char *string,
+  uint32_t length,
+  TSInputEncoding encoding
+) {
+  TSStringInput input = {string, length};
+  return ts_parser_parse(self, old_tree, (TSInput) {
+    &input,
+    ts_string_input_read,
+    encoding,
+  });
+}
+
+void ts_parser_set_wasm_store(TSParser *self, TSWasmStore *store) {
+  ts_wasm_store_delete(self->wasm_store);
+  self->wasm_store = store;
+}
+
+TSWasmStore *ts_parser_take_wasm_store(TSParser *self) {
+  TSWasmStore *result = self->wasm_store;
+  self->wasm_store = NULL;
+  return result;
+}
+
+#undef LOG