Function ExpandMap3Macro

parser/macro.cc:223–250

}

absl::optional<Expr> ExpandMap3Macro(MacroExprFactory& factory, Expr& target,
                                     absl::Span<Expr> args) {
  if (args.size() != 3) {
    return factory.ReportError("map() requires 3 arguments");
  }
  if (!args[0].has_ident_expr() || args[0].ident_expr().name().empty()) {
    return factory.ReportErrorAt(
        args[0], "map() variable name must be a simple identifier");
  }
  if (args[0].ident_expr().name() == kAccumulatorVariableName) {
    return factory.ReportErrorAt(args[1],
                                 absl::StrCat("map() variable name cannot be ",
                                              kAccumulatorVariableName));
  }
  auto init = factory.NewList();
  auto condition = factory.NewBoolConst(true);
  auto accu_ref = factory.NewAccuIdent();
  auto accu_update =
      factory.NewList(factory.NewListElement(std::move(args[2])));
  auto step = factory.NewCall(CelOperator::ADD, std::move(accu_ref),
                              std::move(accu_update));
  step = factory.NewCall(CelOperator::CONDITIONAL, std::move(args[1]),
                         std::move(step), factory.NewAccuIdent());
  return factory.NewComprehension(args[0].ident_expr().name(),
                                  std::move(target), factory.AccuVarName(),
                                  std::move(init), std::move(condition),
                                  std::move(step), factory.NewAccuIdent());
}

Macro MakeMap3Macro() {
  auto status_or_macro = Macro::Receiver(CelOperator::MAP, 3, ExpandMap3Macro);