Method parseArguments

src/TableFunctions/TableFunctionValues.cpp:115–157

template <bool interpret_first_argument_as_structure>
void TableFunctionValues<interpret_first_argument_as_structure>::parseArguments(const ASTPtr & ast_function, ContextPtr context)
{
    ASTs & args_func = ast_function->children;

    if (args_func.size() != 1)
        throw Exception(ErrorCodes::LOGICAL_ERROR, "Table function '{}' must have arguments", getName());

    ASTs & args = args_func.at(0)->children;

    if (args.empty())
        throw Exception(ErrorCodes::TOO_FEW_ARGUMENTS_FOR_FUNCTION, "Table function '{}' requires at least 1 argument", getName());

    if constexpr (interpret_first_argument_as_structure)
    {
        const auto & literal = args[0]->as<const ASTLiteral>();
        String value;
        String error;
        if (args.size() > 1 && literal && literal->value.tryGet(value) && tryParseColumnsListFromString(value, structure, context, error))
        {
            has_structure_in_arguments = true;
            return;
        }
    }

    has_structure_in_arguments = false;
    DataTypes data_types = getTypesFromArgument(args[0], context);
    for (size_t i = 1; i < args.size(); ++i)
    {
        auto arg_types = getTypesFromArgument(args[i], context);
        if (data_types.size() != arg_types.size())
            throw Exception(
                ErrorCodes::CANNOT_EXTRACT_TABLE_STRUCTURE,
                "Cannot determine a common structure for {} function arguments: the amount of columns is different for different arguments",
                getName());
        for (size_t j = 0; j != arg_types.size(); ++j)
            data_types[j] = getLeastSupertype(DataTypes{data_types[j], arg_types[j]});
    }

    NamesAndTypesList names_and_types;
    for (size_t i = 0; i != data_types.size(); ++i)
        names_and_types.emplace_back("c" + std::to_string(i + 1), data_types[i]);
    structure = ColumnsDescription(names_and_types);
}

template <bool interpret_first_argument_as_structure>
ColumnsDescription TableFunctionValues<interpret_first_argument_as_structure>::getActualTableStructure(ContextPtr /*context*/, bool /*is_insert_query*/) const