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c++templatestype-safety

Template typedefs - What's your work around?

C++ 0x has template aliases (sometimes referred to as template typedefs). See here. Current spec of C++ does not.

What do you like to use as work around ? Container objects or Macros ? Do you feel its worth it ?

Solution

  • What do you like to use as work around ? Container objects or Macros ? Do you feel its worth it ?

    The canonical way is to use a metafunction like thus:

    template <typename T>
struct my_string_map {
    typedef std::map<std::string, T> type;
};

// Invoke:

my_string_map<int>::type my_str_int_map;

    This is also used in the STL (allocator::rebind<U>) and in many libraries including Boost. We use it extensively in a bioinformatical library.

    It's bloated, but it's the best alternative 99% of the time. Using macros here is not worth the many downsides.

    (EDIT: I've amended the code to reflect Boost/STL conventions as pointed out by Daniel in his comment.)