diff options
Diffstat (limited to 'src/tree_sitter/stack.c')
| -rw-r--r-- | src/tree_sitter/stack.c | 846 | 
1 files changed, 846 insertions, 0 deletions
| diff --git a/src/tree_sitter/stack.c b/src/tree_sitter/stack.c new file mode 100644 index 0000000000..3e842c99c3 --- /dev/null +++ b/src/tree_sitter/stack.c @@ -0,0 +1,846 @@ +#include "./alloc.h" +#include "./language.h" +#include "./subtree.h" +#include "./array.h" +#include "./stack.h" +#include "./length.h" +#include <assert.h> +#include <stdio.h> + +#define MAX_LINK_COUNT 8 +#define MAX_NODE_POOL_SIZE 50 +#define MAX_ITERATOR_COUNT 64 + +#ifdef _WIN32 +#define inline __forceinline +#else +#define inline static inline __attribute__((always_inline)) +#endif + +typedef struct StackNode StackNode; + +typedef struct { +  StackNode *node; +  Subtree subtree; +  bool is_pending; +} StackLink; + +struct StackNode { +  TSStateId state; +  Length position; +  StackLink links[MAX_LINK_COUNT]; +  short unsigned int link_count; +  uint32_t ref_count; +  unsigned error_cost; +  unsigned node_count; +  int dynamic_precedence; +}; + +typedef struct { +  StackNode *node; +  SubtreeArray subtrees; +  uint32_t subtree_count; +  bool is_pending; +} StackIterator; + +typedef struct { +  void *payload; +  StackIterateCallback callback; +} StackIterateSession; + +typedef Array(StackNode *) StackNodeArray; + +typedef enum { +  StackStatusActive, +  StackStatusPaused, +  StackStatusHalted, +} StackStatus; + +typedef struct { +  StackNode *node; +  Subtree last_external_token; +  StackSummary *summary; +  unsigned node_count_at_last_error; +  TSSymbol lookahead_when_paused; +  StackStatus status; +} StackHead; + +struct Stack { +  Array(StackHead) heads; +  StackSliceArray slices; +  Array(StackIterator) iterators; +  StackNodeArray node_pool; +  StackNode *base_node; +  SubtreePool *subtree_pool; +}; + +typedef unsigned StackAction; +enum { +  StackActionNone, +  StackActionStop = 1, +  StackActionPop = 2, +}; + +typedef StackAction (*StackCallback)(void *, const StackIterator *); + +static void stack_node_retain(StackNode *self) { +  if (!self) +    return; +  assert(self->ref_count > 0); +  self->ref_count++; +  assert(self->ref_count != 0); +} + +static void stack_node_release(StackNode *self, StackNodeArray *pool, SubtreePool *subtree_pool) { +recur: +  assert(self->ref_count != 0); +  self->ref_count--; +  if (self->ref_count > 0) return; + +  StackNode *first_predecessor = NULL; +  if (self->link_count > 0) { +    for (unsigned i = self->link_count - 1; i > 0; i--) { +      StackLink link = self->links[i]; +      if (link.subtree.ptr) ts_subtree_release(subtree_pool, link.subtree); +      stack_node_release(link.node, pool, subtree_pool); +    } +    StackLink link = self->links[0]; +    if (link.subtree.ptr) ts_subtree_release(subtree_pool, link.subtree); +    first_predecessor = self->links[0].node; +  } + +  if (pool->size < MAX_NODE_POOL_SIZE) { +    array_push(pool, self); +  } else { +    ts_free(self); +  } + +  if (first_predecessor) { +    self = first_predecessor; +    goto recur; +  } +} + +static StackNode *stack_node_new(StackNode *previous_node, Subtree subtree, +                                 bool is_pending, TSStateId state, StackNodeArray *pool) { +  StackNode *node = pool->size > 0 ? +    array_pop(pool) : +    ts_malloc(sizeof(StackNode)); +  *node = (StackNode){.ref_count = 1, .link_count = 0, .state = state}; + +  if (previous_node) { +    node->link_count = 1; +    node->links[0] = (StackLink){ +      .node = previous_node, +      .subtree = subtree, +      .is_pending = is_pending, +    }; + +    node->position = previous_node->position; +    node->error_cost = previous_node->error_cost; +    node->dynamic_precedence = previous_node->dynamic_precedence; +    node->node_count = previous_node->node_count; + +    if (subtree.ptr) { +      node->error_cost += ts_subtree_error_cost(subtree); +      node->position = length_add(node->position, ts_subtree_total_size(subtree)); +      node->node_count += ts_subtree_node_count(subtree); +      node->dynamic_precedence += ts_subtree_dynamic_precedence(subtree); +    } +  } else { +    node->position = length_zero(); +    node->error_cost = 0; +  } + +  return node; +} + +static bool stack__subtree_is_equivalent(Subtree left, Subtree right) { +  return +    left.ptr == right.ptr || +    (left.ptr && right.ptr && +     ts_subtree_symbol(left) == ts_subtree_symbol(right) && +     ((ts_subtree_error_cost(left) > 0 && ts_subtree_error_cost(right) > 0) || +      (ts_subtree_padding(left).bytes == ts_subtree_padding(right).bytes && +       ts_subtree_size(left).bytes == ts_subtree_size(right).bytes && +       ts_subtree_child_count(left) == ts_subtree_child_count(right) && +       ts_subtree_extra(left) == ts_subtree_extra(right) && +       ts_subtree_external_scanner_state_eq(left, right)))); +} + +static void stack_node_add_link(StackNode *self, StackLink link, SubtreePool *subtree_pool) { +  if (link.node == self) return; + +  for (int i = 0; i < self->link_count; i++) { +    StackLink *existing_link = &self->links[i]; +    if (stack__subtree_is_equivalent(existing_link->subtree, link.subtree)) { +      // In general, we preserve ambiguities until they are removed from the stack +      // during a pop operation where multiple paths lead to the same node. But in +      // the special case where two links directly connect the same pair of nodes, +      // we can safely remove the ambiguity ahead of time without changing behavior. +      if (existing_link->node == link.node) { +        if ( +          ts_subtree_dynamic_precedence(link.subtree) > +          ts_subtree_dynamic_precedence(existing_link->subtree) +        ) { +          ts_subtree_retain(link.subtree); +          ts_subtree_release(subtree_pool, existing_link->subtree); +          existing_link->subtree = link.subtree; +          self->dynamic_precedence = +            link.node->dynamic_precedence + ts_subtree_dynamic_precedence(link.subtree); +        } +        return; +      } + +      // If the previous nodes are mergeable, merge them recursively. +      if (existing_link->node->state == link.node->state && +          existing_link->node->position.bytes == link.node->position.bytes) { +        for (int j = 0; j < link.node->link_count; j++) { +          stack_node_add_link(existing_link->node, link.node->links[j], subtree_pool); +        } +        int32_t dynamic_precedence = link.node->dynamic_precedence; +        if (link.subtree.ptr) { +          dynamic_precedence += ts_subtree_dynamic_precedence(link.subtree); +        } +        if (dynamic_precedence > self->dynamic_precedence) { +          self->dynamic_precedence = dynamic_precedence; +        } +        return; +      } +    } +  } + +  if (self->link_count == MAX_LINK_COUNT) return; + +  stack_node_retain(link.node); +  unsigned node_count = link.node->node_count; +  int dynamic_precedence = link.node->dynamic_precedence; +  self->links[self->link_count++] = link; + +  if (link.subtree.ptr) { +    ts_subtree_retain(link.subtree); +    node_count += ts_subtree_node_count(link.subtree); +    dynamic_precedence += ts_subtree_dynamic_precedence(link.subtree); +  } + +  if (node_count > self->node_count) self->node_count = node_count; +  if (dynamic_precedence > self->dynamic_precedence) self->dynamic_precedence = dynamic_precedence; +} + +static void stack_head_delete(StackHead *self, StackNodeArray *pool, SubtreePool *subtree_pool) { +  if (self->node) { +    if (self->last_external_token.ptr) { +      ts_subtree_release(subtree_pool, self->last_external_token); +    } +    if (self->summary) { +      array_delete(self->summary); +      ts_free(self->summary); +    } +    stack_node_release(self->node, pool, subtree_pool); +  } +} + +static StackVersion ts_stack__add_version(Stack *self, StackVersion original_version, +                                          StackNode *node) { +  StackHead head = { +    .node = node, +    .node_count_at_last_error = self->heads.contents[original_version].node_count_at_last_error, +    .last_external_token = self->heads.contents[original_version].last_external_token, +    .status = StackStatusActive, +    .lookahead_when_paused = 0, +  }; +  array_push(&self->heads, head); +  stack_node_retain(node); +  if (head.last_external_token.ptr) ts_subtree_retain(head.last_external_token); +  return (StackVersion)(self->heads.size - 1); +} + +static void ts_stack__add_slice(Stack *self, StackVersion original_version, +                                StackNode *node, SubtreeArray *subtrees) { +  for (uint32_t i = self->slices.size - 1; i + 1 > 0; i--) { +    StackVersion version = self->slices.contents[i].version; +    if (self->heads.contents[version].node == node) { +      StackSlice slice = {*subtrees, version}; +      array_insert(&self->slices, i + 1, slice); +      return; +    } +  } + +  StackVersion version = ts_stack__add_version(self, original_version, node); +  StackSlice slice = { *subtrees, version }; +  array_push(&self->slices, slice); +} + +inline StackSliceArray stack__iter(Stack *self, StackVersion version, +                                   StackCallback callback, void *payload, +                                   int goal_subtree_count) { +  array_clear(&self->slices); +  array_clear(&self->iterators); + +  StackHead *head = array_get(&self->heads, version); +  StackIterator iterator = { +    .node = head->node, +    .subtrees = array_new(), +    .subtree_count = 0, +    .is_pending = true, +  }; + +  bool include_subtrees = false; +  if (goal_subtree_count >= 0) { +    include_subtrees = true; +    array_reserve(&iterator.subtrees, goal_subtree_count); +  } + +  array_push(&self->iterators, iterator); + +  while (self->iterators.size > 0) { +    for (uint32_t i = 0, size = self->iterators.size; i < size; i++) { +      StackIterator *iterator = &self->iterators.contents[i]; +      StackNode *node = iterator->node; + +      StackAction action = callback(payload, iterator); +      bool should_pop = action & StackActionPop; +      bool should_stop = action & StackActionStop || node->link_count == 0; + +      if (should_pop) { +        SubtreeArray subtrees = iterator->subtrees; +        if (!should_stop) +          ts_subtree_array_copy(subtrees, &subtrees); +        ts_subtree_array_reverse(&subtrees); +        ts_stack__add_slice( +          self, +          version, +          node, +          &subtrees +        ); +      } + +      if (should_stop) { +        if (!should_pop) +          ts_subtree_array_delete(self->subtree_pool, &iterator->subtrees); +        array_erase(&self->iterators, i); +        i--, size--; +        continue; +      } + +      for (uint32_t j = 1; j <= node->link_count; j++) { +        StackIterator *next_iterator; +        StackLink link; +        if (j == node->link_count) { +          link = node->links[0]; +          next_iterator = &self->iterators.contents[i]; +        } else { +          if (self->iterators.size >= MAX_ITERATOR_COUNT) continue; +          link = node->links[j]; +          StackIterator current_iterator = self->iterators.contents[i]; +          array_push(&self->iterators, current_iterator); +          next_iterator = array_back(&self->iterators); +          ts_subtree_array_copy(next_iterator->subtrees, &next_iterator->subtrees); +        } + +        next_iterator->node = link.node; +        if (link.subtree.ptr) { +          if (include_subtrees) { +            array_push(&next_iterator->subtrees, link.subtree); +            ts_subtree_retain(link.subtree); +          } + +          if (!ts_subtree_extra(link.subtree)) { +            next_iterator->subtree_count++; +            if (!link.is_pending) { +              next_iterator->is_pending = false; +            } +          } +        } else { +          next_iterator->subtree_count++; +          next_iterator->is_pending = false; +        } +      } +    } +  } + +  return self->slices; +} + +Stack *ts_stack_new(SubtreePool *subtree_pool) { +  Stack *self = ts_calloc(1, sizeof(Stack)); + +  array_init(&self->heads); +  array_init(&self->slices); +  array_init(&self->iterators); +  array_init(&self->node_pool); +  array_reserve(&self->heads, 4); +  array_reserve(&self->slices, 4); +  array_reserve(&self->iterators, 4); +  array_reserve(&self->node_pool, MAX_NODE_POOL_SIZE); + +  self->subtree_pool = subtree_pool; +  self->base_node = stack_node_new(NULL, NULL_SUBTREE, false, 1, &self->node_pool); +  ts_stack_clear(self); + +  return self; +} + +void ts_stack_delete(Stack *self) { +  if (self->slices.contents) +    array_delete(&self->slices); +  if (self->iterators.contents) +    array_delete(&self->iterators); +  stack_node_release(self->base_node, &self->node_pool, self->subtree_pool); +  for (uint32_t i = 0; i < self->heads.size; i++) { +    stack_head_delete(&self->heads.contents[i], &self->node_pool, self->subtree_pool); +  } +  array_clear(&self->heads); +  if (self->node_pool.contents) { +    for (uint32_t i = 0; i < self->node_pool.size; i++) +      ts_free(self->node_pool.contents[i]); +    array_delete(&self->node_pool); +  } +  array_delete(&self->heads); +  ts_free(self); +} + +uint32_t ts_stack_version_count(const Stack *self) { +  return self->heads.size; +} + +TSStateId ts_stack_state(const Stack *self, StackVersion version) { +  return array_get(&self->heads, version)->node->state; +} + +Length ts_stack_position(const Stack *self, StackVersion version) { +  return array_get(&self->heads, version)->node->position; +} + +Subtree ts_stack_last_external_token(const Stack *self, StackVersion version) { +  return array_get(&self->heads, version)->last_external_token; +} + +void ts_stack_set_last_external_token(Stack *self, StackVersion version, Subtree token) { +  StackHead *head = array_get(&self->heads, version); +  if (token.ptr) ts_subtree_retain(token); +  if (head->last_external_token.ptr) ts_subtree_release(self->subtree_pool, head->last_external_token); +  head->last_external_token = token; +} + +unsigned ts_stack_error_cost(const Stack *self, StackVersion version) { +  StackHead *head = array_get(&self->heads, version); +  unsigned result = head->node->error_cost; +  if ( +    head->status == StackStatusPaused || +    (head->node->state == ERROR_STATE && !head->node->links[0].subtree.ptr)) { +    result += ERROR_COST_PER_RECOVERY; +  } +  return result; +} + +unsigned ts_stack_node_count_since_error(const Stack *self, StackVersion version) { +  StackHead *head = array_get(&self->heads, version); +  if (head->node->node_count < head->node_count_at_last_error) { +    head->node_count_at_last_error = head->node->node_count; +  } +  return head->node->node_count - head->node_count_at_last_error; +} + +void ts_stack_push(Stack *self, StackVersion version, Subtree subtree, +                   bool pending, TSStateId state) { +  StackHead *head = array_get(&self->heads, version); +  StackNode *new_node = stack_node_new(head->node, subtree, pending, state, &self->node_pool); +  if (!subtree.ptr) head->node_count_at_last_error = new_node->node_count; +  head->node = new_node; +} + +inline StackAction iterate_callback(void *payload, const StackIterator *iterator) { +  StackIterateSession *session = payload; +  session->callback( +    session->payload, +    iterator->node->state, +    iterator->subtree_count +  ); +  return StackActionNone; +} + +void ts_stack_iterate(Stack *self, StackVersion version, +                      StackIterateCallback callback, void *payload) { +  StackIterateSession session = {payload, callback}; +  stack__iter(self, version, iterate_callback, &session, -1); +} + +inline StackAction pop_count_callback(void *payload, const StackIterator *iterator) { +  unsigned *goal_subtree_count = payload; +  if (iterator->subtree_count == *goal_subtree_count) { +    return StackActionPop | StackActionStop; +  } else { +    return StackActionNone; +  } +} + +StackSliceArray ts_stack_pop_count(Stack *self, StackVersion version, uint32_t count) { +  return stack__iter(self, version, pop_count_callback, &count, count); +} + +inline StackAction pop_pending_callback(void *payload, const StackIterator *iterator) { +  if (iterator->subtree_count >= 1) { +    if (iterator->is_pending) { +      return StackActionPop | StackActionStop; +    } else { +      return StackActionStop; +    } +  } else { +    return StackActionNone; +  } +} + +StackSliceArray ts_stack_pop_pending(Stack *self, StackVersion version) { +  StackSliceArray pop = stack__iter(self, version, pop_pending_callback, NULL, 0); +  if (pop.size > 0) { +    ts_stack_renumber_version(self, pop.contents[0].version, version); +    pop.contents[0].version = version; +  } +  return pop; +} + +inline StackAction pop_error_callback(void *payload, const StackIterator *iterator) { +  if (iterator->subtrees.size > 0) { +    bool *found_error = payload; +    if (!*found_error && ts_subtree_is_error(iterator->subtrees.contents[0])) { +      *found_error = true; +      return StackActionPop | StackActionStop; +    } else { +      return StackActionStop; +    } +  } else { +    return StackActionNone; +  } +} + +SubtreeArray ts_stack_pop_error(Stack *self, StackVersion version) { +  StackNode *node = array_get(&self->heads, version)->node; +  for (unsigned i = 0; i < node->link_count; i++) { +    if (node->links[i].subtree.ptr && ts_subtree_is_error(node->links[i].subtree)) { +      bool found_error = false; +      StackSliceArray pop = stack__iter(self, version, pop_error_callback, &found_error, 1); +      if (pop.size > 0) { +        assert(pop.size == 1); +        ts_stack_renumber_version(self, pop.contents[0].version, version); +        return pop.contents[0].subtrees; +      } +      break; +    } +  } +  return (SubtreeArray){.size = 0}; +} + +inline StackAction pop_all_callback(void *payload, const StackIterator *iterator) { +  return iterator->node->link_count == 0 ? StackActionPop : StackActionNone; +} + +StackSliceArray ts_stack_pop_all(Stack *self, StackVersion version) { +  return stack__iter(self, version, pop_all_callback, NULL, 0); +} + +typedef struct { +  StackSummary *summary; +  unsigned max_depth; +} SummarizeStackSession; + +inline StackAction summarize_stack_callback(void *payload, const StackIterator *iterator) { +  SummarizeStackSession *session = payload; +  TSStateId state = iterator->node->state; +  unsigned depth = iterator->subtree_count; +  if (depth > session->max_depth) return StackActionStop; +  for (unsigned i = session->summary->size - 1; i + 1 > 0; i--) { +    StackSummaryEntry entry = session->summary->contents[i]; +    if (entry.depth < depth) break; +    if (entry.depth == depth && entry.state == state) return StackActionNone; +  } +  array_push(session->summary, ((StackSummaryEntry){ +    .position = iterator->node->position, +    .depth = depth, +    .state = state, +  })); +  return StackActionNone; +} + +void ts_stack_record_summary(Stack *self, StackVersion version, unsigned max_depth) { +  SummarizeStackSession session = { +    .summary = ts_malloc(sizeof(StackSummary)), +    .max_depth = max_depth +  }; +  array_init(session.summary); +  stack__iter(self, version, summarize_stack_callback, &session, -1); +  self->heads.contents[version].summary = session.summary; +} + +StackSummary *ts_stack_get_summary(Stack *self, StackVersion version) { +  return array_get(&self->heads, version)->summary; +} + +int ts_stack_dynamic_precedence(Stack *self, StackVersion version) { +  return array_get(&self->heads, version)->node->dynamic_precedence; +} + +bool ts_stack_has_advanced_since_error(const Stack *self, StackVersion version) { +  const StackHead *head = array_get(&self->heads, version); +  const StackNode *node = head->node; +  if (node->error_cost == 0) return true; +  while (node) { +    if (node->link_count > 0) { +      Subtree subtree = node->links[0].subtree; +      if (subtree.ptr) { +        if (ts_subtree_total_bytes(subtree) > 0) { +          return true; +        } else if ( +          node->node_count > head->node_count_at_last_error && +          ts_subtree_error_cost(subtree) == 0 +        ) { +          node = node->links[0].node; +          continue; +        } +      } +    } +    break; +  } +  return false; +} + +void ts_stack_remove_version(Stack *self, StackVersion version) { +  stack_head_delete(array_get(&self->heads, version), &self->node_pool, self->subtree_pool); +  array_erase(&self->heads, version); +} + +void ts_stack_renumber_version(Stack *self, StackVersion v1, StackVersion v2) { +  if (v1 == v2) return; +  assert(v2 < v1); +  assert((uint32_t)v1 < self->heads.size); +  StackHead *source_head = &self->heads.contents[v1]; +  StackHead *target_head = &self->heads.contents[v2]; +  if (target_head->summary && !source_head->summary) { +    source_head->summary = target_head->summary; +    target_head->summary = NULL; +  } +  stack_head_delete(target_head, &self->node_pool, self->subtree_pool); +  *target_head = *source_head; +  array_erase(&self->heads, v1); +} + +void ts_stack_swap_versions(Stack *self, StackVersion v1, StackVersion v2) { +  StackHead temporary_head = self->heads.contents[v1]; +  self->heads.contents[v1] = self->heads.contents[v2]; +  self->heads.contents[v2] = temporary_head; +} + +StackVersion ts_stack_copy_version(Stack *self, StackVersion version) { +  assert(version < self->heads.size); +  array_push(&self->heads, self->heads.contents[version]); +  StackHead *head = array_back(&self->heads); +  stack_node_retain(head->node); +  if (head->last_external_token.ptr) ts_subtree_retain(head->last_external_token); +  head->summary = NULL; +  return self->heads.size - 1; +} + +bool ts_stack_merge(Stack *self, StackVersion version1, StackVersion version2) { +  if (!ts_stack_can_merge(self, version1, version2)) return false; +  StackHead *head1 = &self->heads.contents[version1]; +  StackHead *head2 = &self->heads.contents[version2]; +  for (uint32_t i = 0; i < head2->node->link_count; i++) { +    stack_node_add_link(head1->node, head2->node->links[i], self->subtree_pool); +  } +  if (head1->node->state == ERROR_STATE) { +    head1->node_count_at_last_error = head1->node->node_count; +  } +  ts_stack_remove_version(self, version2); +  return true; +} + +bool ts_stack_can_merge(Stack *self, StackVersion version1, StackVersion version2) { +  StackHead *head1 = &self->heads.contents[version1]; +  StackHead *head2 = &self->heads.contents[version2]; +  return +    head1->status == StackStatusActive && +    head2->status == StackStatusActive && +    head1->node->state == head2->node->state && +    head1->node->position.bytes == head2->node->position.bytes && +    head1->node->error_cost == head2->node->error_cost && +    ts_subtree_external_scanner_state_eq(head1->last_external_token, head2->last_external_token); +} + +void ts_stack_halt(Stack *self, StackVersion version) { +  array_get(&self->heads, version)->status = StackStatusHalted; +} + +void ts_stack_pause(Stack *self, StackVersion version, TSSymbol lookahead) { +  StackHead *head = array_get(&self->heads, version); +  head->status = StackStatusPaused; +  head->lookahead_when_paused = lookahead; +  head->node_count_at_last_error = head->node->node_count; +} + +bool ts_stack_is_active(const Stack *self, StackVersion version) { +  return array_get(&self->heads, version)->status == StackStatusActive; +} + +bool ts_stack_is_halted(const Stack *self, StackVersion version) { +  return array_get(&self->heads, version)->status == StackStatusHalted; +} + +bool ts_stack_is_paused(const Stack *self, StackVersion version) { +  return array_get(&self->heads, version)->status == StackStatusPaused; +} + +TSSymbol ts_stack_resume(Stack *self, StackVersion version) { +  StackHead *head = array_get(&self->heads, version); +  assert(head->status == StackStatusPaused); +  TSSymbol result = head->lookahead_when_paused; +  head->status = StackStatusActive; +  head->lookahead_when_paused = 0; +  return result; +} + +void ts_stack_clear(Stack *self) { +  stack_node_retain(self->base_node); +  for (uint32_t i = 0; i < self->heads.size; i++) { +    stack_head_delete(&self->heads.contents[i], &self->node_pool, self->subtree_pool); +  } +  array_clear(&self->heads); +  array_push(&self->heads, ((StackHead){ +    .node = self->base_node, +    .last_external_token = NULL_SUBTREE, +    .status = StackStatusActive, +    .lookahead_when_paused = 0, +  })); +} + +bool ts_stack_print_dot_graph(Stack *self, const TSLanguage *language, FILE *f) { +  array_reserve(&self->iterators, 32); +  bool was_recording_allocations = ts_toggle_allocation_recording(false); +  if (!f) f = stderr; + +  fprintf(f, "digraph stack {\n"); +  fprintf(f, "rankdir=\"RL\";\n"); +  fprintf(f, "edge [arrowhead=none]\n"); + +  Array(StackNode *) visited_nodes = array_new(); + +  array_clear(&self->iterators); +  for (uint32_t i = 0; i < self->heads.size; i++) { +    StackHead *head = &self->heads.contents[i]; +    if (head->status == StackStatusHalted) continue; + +    fprintf(f, "node_head_%u [shape=none, label=\"\"]\n", i); +    fprintf(f, "node_head_%u -> node_%p [", i, head->node); + +    if (head->status == StackStatusPaused) { +      fprintf(f, "color=red "); +    } +    fprintf(f, +      "label=%u, fontcolor=blue, weight=10000, labeltooltip=\"node_count: %u\nerror_cost: %u", +      i, +      ts_stack_node_count_since_error(self, i), +      ts_stack_error_cost(self, i) +    ); + +    if (head->last_external_token.ptr) { +      const ExternalScannerState *state = &head->last_external_token.ptr->external_scanner_state; +      const char *data = ts_external_scanner_state_data(state); +      fprintf(f, "\nexternal_scanner_state:"); +      for (uint32_t j = 0; j < state->length; j++) fprintf(f, " %2X", data[j]); +    } + +    fprintf(f, "\"]\n"); +    array_push(&self->iterators, ((StackIterator){.node = head->node })); +  } + +  bool all_iterators_done = false; +  while (!all_iterators_done) { +    all_iterators_done = true; + +    for (uint32_t i = 0; i < self->iterators.size; i++) { +      StackIterator iterator = self->iterators.contents[i]; +      StackNode *node = iterator.node; + +      for (uint32_t j = 0; j < visited_nodes.size; j++) { +        if (visited_nodes.contents[j] == node) { +          node = NULL; +          break; +        } +      } + +      if (!node) continue; +      all_iterators_done = false; + +      fprintf(f, "node_%p [", node); +      if (node->state == ERROR_STATE) { +        fprintf(f, "label=\"?\""); +      } else if ( +        node->link_count == 1 && +        node->links[0].subtree.ptr && +        ts_subtree_extra(node->links[0].subtree) +      ) { +        fprintf(f, "shape=point margin=0 label=\"\""); +      } else { +        fprintf(f, "label=\"%d\"", node->state); +      } + +      fprintf( +        f, +        " tooltip=\"position: %u,%u\nnode_count:%u\nerror_cost: %u\ndynamic_precedence: %d\"];\n", +        node->position.extent.row + 1, +        node->position.extent.column, +        node->node_count, +        node->error_cost, +        node->dynamic_precedence +      ); + +      for (int j = 0; j < node->link_count; j++) { +        StackLink link = node->links[j]; +        fprintf(f, "node_%p -> node_%p [", node, link.node); +        if (link.is_pending) fprintf(f, "style=dashed "); +        if (link.subtree.ptr && ts_subtree_extra(link.subtree)) fprintf(f, "fontcolor=gray "); + +        if (!link.subtree.ptr) { +          fprintf(f, "color=red"); +        } else { +          fprintf(f, "label=\""); +          bool quoted = ts_subtree_visible(link.subtree) && !ts_subtree_named(link.subtree); +          if (quoted) fprintf(f, "'"); +          const char *name = ts_language_symbol_name(language, ts_subtree_symbol(link.subtree)); +          for (const char *c = name; *c; c++) { +            if (*c == '\"' || *c == '\\') fprintf(f, "\\"); +            fprintf(f, "%c", *c); +          } +          if (quoted) fprintf(f, "'"); +          fprintf(f, "\""); +          fprintf( +            f, +            "labeltooltip=\"error_cost: %u\ndynamic_precedence: %u\"", +            ts_subtree_error_cost(link.subtree), +            ts_subtree_dynamic_precedence(link.subtree) +          ); +        } + +        fprintf(f, "];\n"); + +        StackIterator *next_iterator; +        if (j == 0) { +          next_iterator = &self->iterators.contents[i]; +        } else { +          array_push(&self->iterators, iterator); +          next_iterator = array_back(&self->iterators); +        } +        next_iterator->node = link.node; +      } + +      array_push(&visited_nodes, node); +    } +  } + +  fprintf(f, "}\n"); + +  array_delete(&visited_nodes); +  ts_toggle_allocation_recording(was_recording_allocations); +  return true; +} + +#undef inline | 
