Function is_operator_token

engine/src/parser/expression_utils.cpp:493–497

}

bool is_operator_token(const std::string & token) {
	// can't use is_unary_operator_token(token) || is_binary_operator_token(token);
	// need to work with calcite operators too i.e. CASE, CAST, etc
	return !is_literal(token) && !is_var_column(token) && !is_SQL_data_type(token);
}

bool is_literal(const std::string & token) {
	return is_null(token) || is_bool(token) || is_number(token) || is_date(token) || is_string(token) ||