tree-sitter/src/compiler/parse_table.cc

#include "compiler/parse_table.h"
#include <string>

namespace tree_sitter {

using std::string;
using std::ostream;
using std::to_string;
using std::set;
using std::vector;
using rules::Symbol;

ParseAction::ParseAction(ParseActionType type, ParseStateId state_index,
                         Symbol symbol, size_t consumed_symbol_count,
                         set<int> precedence_values,
                         rules::Associativity associativity,
                         int production_id)
    : type(type),
      symbol(symbol),
      state_index(state_index),
      consumed_symbol_count(consumed_symbol_count),
      precedence_values(precedence_values),
      associativity(associativity),
      production_id(production_id) {}

ParseAction::ParseAction()
    : type(ParseActionTypeError),
      symbol(Symbol(-1)),
      state_index(-1),
      consumed_symbol_count(0),
      associativity(rules::AssociativityUnspecified) {}

ParseAction ParseAction::Error() {
  return ParseAction();
}

ParseAction ParseAction::Accept() {
  ParseAction action;
  action.type = ParseActionTypeAccept;
  return action;
}

ParseAction ParseAction::Shift(ParseStateId state_index,
                               set<int> precedence_values) {
  return ParseAction(ParseActionTypeShift, state_index, Symbol(-1), 0,
                     precedence_values, rules::AssociativityUnspecified, -1);
}

ParseAction ParseAction::ShiftExtra() {
  ParseAction action;
  action.type = ParseActionTypeShiftExtra;
  return action;
}

ParseAction ParseAction::ReduceExtra(Symbol symbol) {
  ParseAction action;
  action.type = ParseActionTypeReduceExtra;
  action.symbol = symbol;
  return action;
}

ParseAction ParseAction::Reduce(Symbol symbol, size_t consumed_symbol_count,
                                int precedence, rules::Associativity associativity,
                                int production_id) {
  return ParseAction(ParseActionTypeReduce, 0, symbol, consumed_symbol_count,
                     { precedence }, associativity, production_id);
}

bool ParseAction::operator==(const ParseAction &other) const {
  bool types_eq = type == other.type;
  bool symbols_eq = symbol == other.symbol;
  bool state_indices_eq = state_index == other.state_index;
  bool consumed_symbol_counts_eq =
      consumed_symbol_count == other.consumed_symbol_count;
  return types_eq && symbols_eq && state_indices_eq && consumed_symbol_counts_eq;
}

bool ParseAction::operator<(const ParseAction &other) const {
  if (type < other.type) return true;
  if (other.type < type) return false;
  if (symbol < other.symbol) return true;
  if (other.symbol < symbol) return false;
  if (state_index < other.state_index) return true;
  if (other.state_index < state_index) return false;
  return consumed_symbol_count < other.consumed_symbol_count;
}

ostream &operator<<(ostream &stream, const ParseAction &action) {
  switch (action.type) {
    case ParseActionTypeError:
      return stream << string("#<error>");
    case ParseActionTypeAccept:
      return stream << string("#<accept>");
    case ParseActionTypeShift:
      return stream << (string("#<shift ") + to_string(action.state_index) +
                        ">");
    case ParseActionTypeShiftExtra:
      return stream << string("#<shift_extra");
    case ParseActionTypeReduceExtra:
      return stream << ("#<reduce_extra sym" + to_string(action.symbol.index) +
                        ">");
    case ParseActionTypeReduce:
      return stream << ("#<reduce sym" + to_string(action.symbol.index) + " " +
                        to_string(action.consumed_symbol_count) + ">");
    default:
      return stream;
  }
}

ParseState::ParseState() : lex_state_id(-1) {}

set<Symbol> ParseState::expected_inputs() const {
  set<Symbol> result;
  for (auto &pair : actions)
    result.insert(pair.first);
  return result;
}

ostream &operator<<(ostream &stream, const ParseState &state) {
  stream << string("#<parse_state ");
  bool started = false;
  for (auto pair : state.actions) {
    if (started)
      stream << string(", ");
    stream << pair.first << string(" => {");
    for (auto &action : pair.second) {
      stream << string(" ") << action;
    }
    stream << string("}");
    started = true;
  }
  stream << string(">");
  return stream;
}

ParseStateId ParseTable::add_state() {
  states.push_back(ParseState());
  return states.size() - 1;
}

ParseAction &ParseTable::set_action(ParseStateId id, Symbol symbol, ParseAction action) {
  symbols.insert(symbol);
  states[id].actions[symbol] = vector<ParseAction>({ action });
  return *states[id].actions[symbol].begin();
}

ParseAction &ParseTable::add_action(ParseStateId id, Symbol symbol, ParseAction action) {
  symbols.insert(symbol);
  states[id].actions[symbol].push_back(action);
  return *states[id].actions[symbol].rbegin();
}

}  // namespace tree_sitter