Method generate

src/sys/expressionparser.cxx:231–233

Evaluate expression, check it's a bool, and return 1 or 0

  /// Evaluate expression, check it's a bool, and return 1 or 0
  double generate(const Context& ctx) override {
    return toBool(expr->generate(ctx)) ? 0.0 : 1.0;
  }

  std::string str() const override { return "!"s + expr->str(); }