1 files changed, 714 insertions, 0 deletions

diff --git a/vendor/github.com/mitjafelicijan/go-tree-sitter/tree_cursor.c b/vendor/github.com/mitjafelicijan/go-tree-sitter/tree_cursor.c
new file mode 100644
index 0000000..c1a3d8a
--- /dev/null
+++ b/vendor/github.com/mitjafelicijan/go-tree-sitter/tree_cursor.c
@@ -0,0 +1,714 @@
+#include "api.h"
+#include "./alloc.h"
+#include "./tree_cursor.h"
+#include "./language.h"
+#include "./tree.h"
+
+typedef struct {
+  Subtree parent;
+  const TSTree *tree;
+  Length position;
+  uint32_t child_index;
+  uint32_t structural_child_index;
+  uint32_t descendant_index;
+  const TSSymbol *alias_sequence;
+} CursorChildIterator;
+
+// CursorChildIterator
+
+static inline bool ts_tree_cursor_is_entry_visible(const TreeCursor *self, uint32_t index) {
+  TreeCursorEntry *entry = &self->stack.contents[index];
+  if (index == 0 || ts_subtree_visible(*entry->subtree)) {
+    return true;
+  } else if (!ts_subtree_extra(*entry->subtree)) {
+    TreeCursorEntry *parent_entry = &self->stack.contents[index - 1];
+    return ts_language_alias_at(
+      self->tree->language,
+      parent_entry->subtree->ptr->production_id,
+      entry->structural_child_index
+    );
+  } else {
+    return false;
+  }
+}
+
+static inline CursorChildIterator ts_tree_cursor_iterate_children(const TreeCursor *self) {
+  TreeCursorEntry *last_entry = array_back(&self->stack);
+  if (ts_subtree_child_count(*last_entry->subtree) == 0) {
+    return (CursorChildIterator) {NULL_SUBTREE, self->tree, length_zero(), 0, 0, 0, NULL};
+  }
+  const TSSymbol *alias_sequence = ts_language_alias_sequence(
+    self->tree->language,
+    last_entry->subtree->ptr->production_id
+  );
+
+  uint32_t descendant_index = last_entry->descendant_index;
+  if (ts_tree_cursor_is_entry_visible(self, self->stack.size - 1)) {
+    descendant_index += 1;
+  }
+
+  return (CursorChildIterator) {
+    .tree = self->tree,
+    .parent = *last_entry->subtree,
+    .position = last_entry->position,
+    .child_index = 0,
+    .structural_child_index = 0,
+    .descendant_index = descendant_index,
+    .alias_sequence = alias_sequence,
+  };
+}
+
+static inline bool ts_tree_cursor_child_iterator_next(
+  CursorChildIterator *self,
+  TreeCursorEntry *result,
+  bool *visible
+) {
+  if (!self->parent.ptr || self->child_index == self->parent.ptr->child_count) return false;
+  const Subtree *child = &ts_subtree_children(self->parent)[self->child_index];
+  *result = (TreeCursorEntry) {
+    .subtree = child,
+    .position = self->position,
+    .child_index = self->child_index,
+    .structural_child_index = self->structural_child_index,
+    .descendant_index = self->descendant_index,
+  };
+  *visible = ts_subtree_visible(*child);
+  bool extra = ts_subtree_extra(*child);
+  if (!extra) {
+    if (self->alias_sequence) {
+      *visible |= self->alias_sequence[self->structural_child_index];
+    }
+    self->structural_child_index++;
+  }
+
+  self->descendant_index += ts_subtree_visible_descendant_count(*child);
+  if (*visible) {
+    self->descendant_index += 1;
+  }
+
+  self->position = length_add(self->position, ts_subtree_size(*child));
+  self->child_index++;
+
+  if (self->child_index < self->parent.ptr->child_count) {
+    Subtree next_child = ts_subtree_children(self->parent)[self->child_index];
+    self->position = length_add(self->position, ts_subtree_padding(next_child));
+  }
+
+  return true;
+}
+
+// Return a position that, when `b` is added to it, yields `a`. This
+// can only be computed if `b` has zero rows. Otherwise, this function
+// returns `LENGTH_UNDEFINED`, and the caller needs to recompute
+// the position some other way.
+static inline Length length_backtrack(Length a, Length b) {
+  if (length_is_undefined(a) || b.extent.row != 0) {
+    return LENGTH_UNDEFINED;
+  }
+
+  Length result;
+  result.bytes = a.bytes - b.bytes;
+  result.extent.row = a.extent.row;
+  result.extent.column = a.extent.column - b.extent.column;
+  return result;
+}
+
+static inline bool ts_tree_cursor_child_iterator_previous(
+  CursorChildIterator *self,
+  TreeCursorEntry *result,
+  bool *visible
+) {
+  // this is mostly a reverse `ts_tree_cursor_child_iterator_next` taking into
+  // account unsigned underflow
+  if (!self->parent.ptr || (int8_t)self->child_index == -1) return false;
+  const Subtree *child = &ts_subtree_children(self->parent)[self->child_index];
+  *result = (TreeCursorEntry) {
+    .subtree = child,
+    .position = self->position,
+    .child_index = self->child_index,
+    .structural_child_index = self->structural_child_index,
+  };
+  *visible = ts_subtree_visible(*child);
+  bool extra = ts_subtree_extra(*child);
+  if (!extra && self->alias_sequence) {
+    *visible |= self->alias_sequence[self->structural_child_index];
+    self->structural_child_index--;
+  }
+
+  self->position = length_backtrack(self->position, ts_subtree_padding(*child));
+  self->child_index--;
+
+  // unsigned can underflow so compare it to child_count
+  if (self->child_index < self->parent.ptr->child_count) {
+    Subtree previous_child = ts_subtree_children(self->parent)[self->child_index];
+    Length size = ts_subtree_size(previous_child);
+    self->position = length_backtrack(self->position, size);
+  }
+
+  return true;
+}
+
+// TSTreeCursor - lifecycle
+
+TSTreeCursor ts_tree_cursor_new(TSNode node) {
+  TSTreeCursor self = {NULL, NULL, {0, 0, 0}};
+  ts_tree_cursor_init((TreeCursor *)&self, node);
+  return self;
+}
+
+void ts_tree_cursor_reset(TSTreeCursor *_self, TSNode node) {
+  ts_tree_cursor_init((TreeCursor *)_self, node);
+}
+
+void ts_tree_cursor_init(TreeCursor *self, TSNode node) {
+  self->tree = node.tree;
+  self->root_alias_symbol = node.context[3];
+  array_clear(&self->stack);
+  array_push(&self->stack, ((TreeCursorEntry) {
+    .subtree = (const Subtree *)node.id,
+    .position = {
+      ts_node_start_byte(node),
+      ts_node_start_point(node)
+    },
+    .child_index = 0,
+    .structural_child_index = 0,
+    .descendant_index = 0,
+  }));
+}
+
+void ts_tree_cursor_delete(TSTreeCursor *_self) {
+  TreeCursor *self = (TreeCursor *)_self;
+  array_delete(&self->stack);
+}
+
+// TSTreeCursor - walking the tree
+
+TreeCursorStep ts_tree_cursor_goto_first_child_internal(TSTreeCursor *_self) {
+  TreeCursor *self = (TreeCursor *)_self;
+  bool visible;
+  TreeCursorEntry entry;
+  CursorChildIterator iterator = ts_tree_cursor_iterate_children(self);
+  while (ts_tree_cursor_child_iterator_next(&iterator, &entry, &visible)) {
+    if (visible) {
+      array_push(&self->stack, entry);
+      return TreeCursorStepVisible;
+    }
+    if (ts_subtree_visible_child_count(*entry.subtree) > 0) {
+      array_push(&self->stack, entry);
+      return TreeCursorStepHidden;
+    }
+  }
+  return TreeCursorStepNone;
+}
+
+bool ts_tree_cursor_goto_first_child(TSTreeCursor *self) {
+  for (;;) {
+    switch (ts_tree_cursor_goto_first_child_internal(self)) {
+      case TreeCursorStepHidden:
+        continue;
+      case TreeCursorStepVisible:
+        return true;
+      default:
+        return false;
+    }
+  }
+  return false;
+}
+
+TreeCursorStep ts_tree_cursor_goto_last_child_internal(TSTreeCursor *_self) {
+  TreeCursor *self = (TreeCursor *)_self;
+  bool visible;
+  TreeCursorEntry entry;
+  CursorChildIterator iterator = ts_tree_cursor_iterate_children(self);
+  if (!iterator.parent.ptr || iterator.parent.ptr->child_count == 0) return TreeCursorStepNone;
+
+  TreeCursorEntry last_entry = {0};
+  TreeCursorStep last_step = TreeCursorStepNone;
+  while (ts_tree_cursor_child_iterator_next(&iterator, &entry, &visible)) {
+    if (visible) {
+      last_entry = entry;
+      last_step = TreeCursorStepVisible;
+    }
+    else if (ts_subtree_visible_child_count(*entry.subtree) > 0) {
+      last_entry = entry;
+      last_step = TreeCursorStepHidden;
+    }
+  }
+  if (last_entry.subtree) {
+    array_push(&self->stack, last_entry);
+    return last_step;
+  }
+
+  return TreeCursorStepNone;
+}
+
+bool ts_tree_cursor_goto_last_child(TSTreeCursor *self) {
+  for (;;) {
+    switch (ts_tree_cursor_goto_last_child_internal(self)) {
+      case TreeCursorStepHidden:
+        continue;
+      case TreeCursorStepVisible:
+        return true;
+      default:
+        return false;
+    }
+  }
+  return false;
+}
+
+static inline int64_t ts_tree_cursor_goto_first_child_for_byte_and_point(
+  TSTreeCursor *_self,
+  uint32_t goal_byte,
+  TSPoint goal_point
+) {
+  TreeCursor *self = (TreeCursor *)_self;
+  uint32_t initial_size = self->stack.size;
+  uint32_t visible_child_index = 0;
+
+  bool did_descend;
+  do {
+    did_descend = false;
+
+    bool visible;
+    TreeCursorEntry entry;
+    CursorChildIterator iterator = ts_tree_cursor_iterate_children(self);
+    while (ts_tree_cursor_child_iterator_next(&iterator, &entry, &visible)) {
+      Length entry_end = length_add(entry.position, ts_subtree_size(*entry.subtree));
+      bool at_goal = entry_end.bytes >= goal_byte && point_gte(entry_end.extent, goal_point);
+      uint32_t visible_child_count = ts_subtree_visible_child_count(*entry.subtree);
+      if (at_goal) {
+        if (visible) {
+          array_push(&self->stack, entry);
+          return visible_child_index;
+        }
+        if (visible_child_count > 0) {
+          array_push(&self->stack, entry);
+          did_descend = true;
+          break;
+        }
+      } else if (visible) {
+        visible_child_index++;
+      } else {
+        visible_child_index += visible_child_count;
+      }
+    }
+  } while (did_descend);
+
+  self->stack.size = initial_size;
+  return -1;
+}
+
+int64_t ts_tree_cursor_goto_first_child_for_byte(TSTreeCursor *self, uint32_t goal_byte) {
+  return ts_tree_cursor_goto_first_child_for_byte_and_point(self, goal_byte, POINT_ZERO);
+}
+
+int64_t ts_tree_cursor_goto_first_child_for_point(TSTreeCursor *self, TSPoint goal_point) {
+  return ts_tree_cursor_goto_first_child_for_byte_and_point(self, 0, goal_point);
+}
+
+TreeCursorStep ts_tree_cursor_goto_sibling_internal(
+    TSTreeCursor *_self,
+    bool (*advance)(CursorChildIterator *, TreeCursorEntry *, bool *)) {
+  TreeCursor *self = (TreeCursor *)_self;
+  uint32_t initial_size = self->stack.size;
+
+  while (self->stack.size > 1) {
+    TreeCursorEntry entry = array_pop(&self->stack);
+    CursorChildIterator iterator = ts_tree_cursor_iterate_children(self);
+    iterator.child_index = entry.child_index;
+    iterator.structural_child_index = entry.structural_child_index;
+    iterator.position = entry.position;
+    iterator.descendant_index = entry.descendant_index;
+
+    bool visible = false;
+    advance(&iterator, &entry, &visible);
+    if (visible && self->stack.size + 1 < initial_size) break;
+
+    while (advance(&iterator, &entry, &visible)) {
+      if (visible) {
+        array_push(&self->stack, entry);
+        return TreeCursorStepVisible;
+      }
+
+      if (ts_subtree_visible_child_count(*entry.subtree)) {
+        array_push(&self->stack, entry);
+        return TreeCursorStepHidden;
+      }
+    }
+  }
+
+  self->stack.size = initial_size;
+  return TreeCursorStepNone;
+}
+
+TreeCursorStep ts_tree_cursor_goto_next_sibling_internal(TSTreeCursor *_self) {
+  return ts_tree_cursor_goto_sibling_internal(_self, ts_tree_cursor_child_iterator_next);
+}
+
+bool ts_tree_cursor_goto_next_sibling(TSTreeCursor *self) {
+  switch (ts_tree_cursor_goto_next_sibling_internal(self)) {
+    case TreeCursorStepHidden:
+      ts_tree_cursor_goto_first_child(self);
+      return true;
+    case TreeCursorStepVisible:
+      return true;
+    default:
+      return false;
+  }
+}
+
+TreeCursorStep ts_tree_cursor_goto_previous_sibling_internal(TSTreeCursor *_self) {
+  // since subtracting across row loses column information, we may have to
+  // restore it
+  TreeCursor *self = (TreeCursor *)_self;
+
+  // for that, save current position before traversing
+  TreeCursorStep step = ts_tree_cursor_goto_sibling_internal(
+      _self, ts_tree_cursor_child_iterator_previous);
+  if (step == TreeCursorStepNone)
+    return step;
+
+  // if length is already valid, there's no need to recompute it
+  if (!length_is_undefined(array_back(&self->stack)->position))
+    return step;
+
+  // restore position from the parent node
+  const TreeCursorEntry *parent = &self->stack.contents[self->stack.size - 2];
+  Length position = parent->position;
+  uint32_t child_index = array_back(&self->stack)->child_index;
+  const Subtree *children = ts_subtree_children((*(parent->subtree)));
+
+  if (child_index > 0) {
+    // skip first child padding since its position should match the position of the parent
+    position = length_add(position, ts_subtree_size(children[0]));
+    for (uint32_t i = 1; i < child_index; ++i) {
+      position = length_add(position, ts_subtree_total_size(children[i]));
+    }
+    position = length_add(position, ts_subtree_padding(children[child_index]));
+  }
+
+  array_back(&self->stack)->position = position;
+
+  return step;
+}
+
+bool ts_tree_cursor_goto_previous_sibling(TSTreeCursor *self) {
+  switch (ts_tree_cursor_goto_previous_sibling_internal(self)) {
+    case TreeCursorStepHidden:
+      ts_tree_cursor_goto_last_child(self);
+      return true;
+    case TreeCursorStepVisible:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool ts_tree_cursor_goto_parent(TSTreeCursor *_self) {
+  TreeCursor *self = (TreeCursor *)_self;
+  for (unsigned i = self->stack.size - 2; i + 1 > 0; i--) {
+    if (ts_tree_cursor_is_entry_visible(self, i)) {
+      self->stack.size = i + 1;
+      return true;
+    }
+  }
+  return false;
+}
+
+void ts_tree_cursor_goto_descendant(
+  TSTreeCursor *_self,
+  uint32_t goal_descendant_index
+) {
+  TreeCursor *self = (TreeCursor *)_self;
+
+  // Ascend to the lowest ancestor that contains the goal node.
+  for (;;) {
+    uint32_t i = self->stack.size - 1;
+    TreeCursorEntry *entry = &self->stack.contents[i];
+    uint32_t next_descendant_index =
+      entry->descendant_index +
+      (ts_tree_cursor_is_entry_visible(self, i) ? 1 : 0) +
+      ts_subtree_visible_descendant_count(*entry->subtree);
+    if (
+      (entry->descendant_index <= goal_descendant_index) &&
+      (next_descendant_index > goal_descendant_index)
+    ) {
+      break;
+    } else if (self->stack.size <= 1) {
+      return;
+    } else {
+      self->stack.size--;
+    }
+  }
+
+  // Descend to the goal node.
+  bool did_descend = true;
+  do {
+    did_descend = false;
+    bool visible;
+    TreeCursorEntry entry;
+    CursorChildIterator iterator = ts_tree_cursor_iterate_children(self);
+    if (iterator.descendant_index > goal_descendant_index) {
+      return;
+    }
+
+    while (ts_tree_cursor_child_iterator_next(&iterator, &entry, &visible)) {
+      if (iterator.descendant_index > goal_descendant_index) {
+        array_push(&self->stack, entry);
+        if (visible && entry.descendant_index == goal_descendant_index) {
+          return;
+        } else {
+          did_descend = true;
+          break;
+        }
+      }
+    }
+  } while (did_descend);
+}
+
+uint32_t ts_tree_cursor_current_descendant_index(const TSTreeCursor *_self) {
+  const TreeCursor *self = (const TreeCursor *)_self;
+  TreeCursorEntry *last_entry = array_back(&self->stack);
+  return last_entry->descendant_index;
+}
+
+TSNode ts_tree_cursor_current_node(const TSTreeCursor *_self) {
+  const TreeCursor *self = (const TreeCursor *)_self;
+  TreeCursorEntry *last_entry = array_back(&self->stack);
+  TSSymbol alias_symbol = self->root_alias_symbol;
+  if (self->stack.size > 1 && !ts_subtree_extra(*last_entry->subtree)) {
+    TreeCursorEntry *parent_entry = &self->stack.contents[self->stack.size - 2];
+    alias_symbol = ts_language_alias_at(
+      self->tree->language,
+      parent_entry->subtree->ptr->production_id,
+      last_entry->structural_child_index
+    );
+  }
+  return ts_node_new(
+    self->tree,
+    last_entry->subtree,
+    last_entry->position,
+    alias_symbol
+  );
+}
+
+// Private - Get various facts about the current node that are needed
+// when executing tree queries.
+void ts_tree_cursor_current_status(
+  const TSTreeCursor *_self,
+  TSFieldId *field_id,
+  bool *has_later_siblings,
+  bool *has_later_named_siblings,
+  bool *can_have_later_siblings_with_this_field,
+  TSSymbol *supertypes,
+  unsigned *supertype_count
+) {
+  const TreeCursor *self = (const TreeCursor *)_self;
+  unsigned max_supertypes = *supertype_count;
+  *field_id = 0;
+  *supertype_count = 0;
+  *has_later_siblings = false;
+  *has_later_named_siblings = false;
+  *can_have_later_siblings_with_this_field = false;
+
+  // Walk up the tree, visiting the current node and its invisible ancestors,
+  // because fields can refer to nodes through invisible *wrapper* nodes,
+  for (unsigned i = self->stack.size - 1; i > 0; i--) {
+    TreeCursorEntry *entry = &self->stack.contents[i];
+    TreeCursorEntry *parent_entry = &self->stack.contents[i - 1];
+
+    const TSSymbol *alias_sequence = ts_language_alias_sequence(
+      self->tree->language,
+      parent_entry->subtree->ptr->production_id
+    );
+
+    #define subtree_symbol(subtree, structural_child_index) \
+      ((                                                    \
+        !ts_subtree_extra(subtree) &&                       \
+        alias_sequence &&                                   \
+        alias_sequence[structural_child_index]              \
+      ) ?                                                   \
+        alias_sequence[structural_child_index] :            \
+        ts_subtree_symbol(subtree))
+
+    // Stop walking up when a visible ancestor is found.
+    TSSymbol entry_symbol = subtree_symbol(
+      *entry->subtree,
+      entry->structural_child_index
+    );
+    TSSymbolMetadata entry_metadata = ts_language_symbol_metadata(
+      self->tree->language,
+      entry_symbol
+    );
+    if (i != self->stack.size - 1 && entry_metadata.visible) break;
+
+    // Record any supertypes
+    if (entry_metadata.supertype && *supertype_count < max_supertypes) {
+      supertypes[*supertype_count] = entry_symbol;
+      (*supertype_count)++;
+    }
+
+    // Determine if the current node has later siblings.
+    if (!*has_later_siblings) {
+      unsigned sibling_count = parent_entry->subtree->ptr->child_count;
+      unsigned structural_child_index = entry->structural_child_index;
+      if (!ts_subtree_extra(*entry->subtree)) structural_child_index++;
+      for (unsigned j = entry->child_index + 1; j < sibling_count; j++) {
+        Subtree sibling = ts_subtree_children(*parent_entry->subtree)[j];
+        TSSymbolMetadata sibling_metadata = ts_language_symbol_metadata(
+          self->tree->language,
+          subtree_symbol(sibling, structural_child_index)
+        );
+        if (sibling_metadata.visible) {
+          *has_later_siblings = true;
+          if (*has_later_named_siblings) break;
+          if (sibling_metadata.named) {
+            *has_later_named_siblings = true;
+            break;
+          }
+        } else if (ts_subtree_visible_child_count(sibling) > 0) {
+          *has_later_siblings = true;
+          if (*has_later_named_siblings) break;
+          if (sibling.ptr->named_child_count > 0) {
+            *has_later_named_siblings = true;
+            break;
+          }
+        }
+        if (!ts_subtree_extra(sibling)) structural_child_index++;
+      }
+    }
+
+    #undef subtree_symbol
+
+    if (!ts_subtree_extra(*entry->subtree)) {
+      const TSFieldMapEntry *field_map, *field_map_end;
+      ts_language_field_map(
+        self->tree->language,
+        parent_entry->subtree->ptr->production_id,
+        &field_map, &field_map_end
+      );
+
+      // Look for a field name associated with the current node.
+      if (!*field_id) {
+        for (const TSFieldMapEntry *map = field_map; map < field_map_end; map++) {
+          if (!map->inherited && map->child_index == entry->structural_child_index) {
+            *field_id = map->field_id;
+            break;
+          }
+        }
+      }
+
+      // Determine if the current node can have later siblings with the same field name.
+      if (*field_id) {
+        for (const TSFieldMapEntry *map = field_map; map < field_map_end; map++) {
+          if (
+            map->field_id == *field_id &&
+            map->child_index > entry->structural_child_index
+          ) {
+            *can_have_later_siblings_with_this_field = true;
+            break;
+          }
+        }
+      }
+    }
+  }
+}
+
+uint32_t ts_tree_cursor_current_depth(const TSTreeCursor *_self) {
+  const TreeCursor *self = (const TreeCursor *)_self;
+  uint32_t depth = 0;
+  for (unsigned i = 1; i < self->stack.size; i++) {
+    if (ts_tree_cursor_is_entry_visible(self, i)) {
+      depth++;
+    }
+  }
+  return depth;
+}
+
+TSNode ts_tree_cursor_parent_node(const TSTreeCursor *_self) {
+  const TreeCursor *self = (const TreeCursor *)_self;
+  for (int i = (int)self->stack.size - 2; i >= 0; i--) {
+    TreeCursorEntry *entry = &self->stack.contents[i];
+    bool is_visible = true;
+    TSSymbol alias_symbol = 0;
+    if (i > 0) {
+      TreeCursorEntry *parent_entry = &self->stack.contents[i - 1];
+      alias_symbol = ts_language_alias_at(
+        self->tree->language,
+        parent_entry->subtree->ptr->production_id,
+        entry->structural_child_index
+      );
+      is_visible = (alias_symbol != 0) || ts_subtree_visible(*entry->subtree);
+    }
+    if (is_visible) {
+      return ts_node_new(
+        self->tree,
+        entry->subtree,
+        entry->position,
+        alias_symbol
+      );
+    }
+  }
+  return ts_node_new(NULL, NULL, length_zero(), 0);
+}
+
+TSFieldId ts_tree_cursor_current_field_id(const TSTreeCursor *_self) {
+  const TreeCursor *self = (const TreeCursor *)_self;
+
+  // Walk up the tree, visiting the current node and its invisible ancestors.
+  for (unsigned i = self->stack.size - 1; i > 0; i--) {
+    TreeCursorEntry *entry = &self->stack.contents[i];
+    TreeCursorEntry *parent_entry = &self->stack.contents[i - 1];
+
+    // Stop walking up when another visible node is found.
+    if (
+      i != self->stack.size - 1 &&
+      ts_tree_cursor_is_entry_visible(self, i)
+    ) break;
+
+    if (ts_subtree_extra(*entry->subtree)) break;
+
+    const TSFieldMapEntry *field_map, *field_map_end;
+    ts_language_field_map(
+      self->tree->language,
+      parent_entry->subtree->ptr->production_id,
+      &field_map, &field_map_end
+    );
+    for (const TSFieldMapEntry *map = field_map; map < field_map_end; map++) {
+      if (!map->inherited && map->child_index == entry->structural_child_index) {
+        return map->field_id;
+      }
+    }
+  }
+  return 0;
+}
+
+const char *ts_tree_cursor_current_field_name(const TSTreeCursor *_self) {
+  TSFieldId id = ts_tree_cursor_current_field_id(_self);
+  if (id) {
+    const TreeCursor *self = (const TreeCursor *)_self;
+    return self->tree->language->field_names[id];
+  } else {
+    return NULL;
+  }
+}
+
+TSTreeCursor ts_tree_cursor_copy(const TSTreeCursor *_cursor) {
+  const TreeCursor *cursor = (const TreeCursor *)_cursor;
+  TSTreeCursor res = {NULL, NULL, {0, 0}};
+  TreeCursor *copy = (TreeCursor *)&res;
+  copy->tree = cursor->tree;
+  copy->root_alias_symbol = cursor->root_alias_symbol;
+  array_init(&copy->stack);
+  array_push_all(&copy->stack, &cursor->stack);
+  return res;
+}
+
+void ts_tree_cursor_reset_to(TSTreeCursor *_dst, const TSTreeCursor *_src) {
+  const TreeCursor *cursor = (const TreeCursor *)_src;
+  TreeCursor *copy = (TreeCursor *)_dst;
+  copy->tree = cursor->tree;
+  copy->root_alias_symbol = cursor->root_alias_symbol;
+  array_clear(&copy->stack);
+  array_push_all(&copy->stack, &cursor->stack);
+}