Concepts substitute/emulation for C++ (17)?

With concepts not coming until C++20 and otherwise being exclusive to GCC, is there a way to sort of workaround I can do? I did see some old pre-C++11 how-tos but there was a 'to do' placeholder for static_assert, in regards for template-based concept workarounds.

Basically, I want to define a concept that represents a container (ex: standard library's string, vector, array, map classes, and so on). With the current draft for concepts, I could just define the Container concept with "requires push_back(), front(), last(), etc" willy nilly. I do know there's a way to sort of do this without concepts, but my searches haven't yielded any suitable answers.

Think I found my answer just now after a bit more digging in Boost's concept check component. Including boost/concept_check.hpp provides me with a few options, including Container (Container )

Look up void_t.
The error messages will be tricky if something goes wrong, but you can emulate concepts pretty well.
std::void_t - cppreference.com

Seems confusing, but I see some relation to concepts as far as that goes. Thanks.

Essentially what you can do is:

Code:

---

// Define is_containter<T> with SFINAE/void_t/magic

template<typename T>
void foo(T t) {
  static_assert(is_container<T>::value, "requires is_container");
  // ...
}

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Quote:

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Originally Posted by manasij7479

Essentially what you can do is:

Code:

---

// Define is_containter<T> with SFINAE/void_t/magic

template<typename T>
void foo(T t) {
  static_assert(is_container<T>::value, "requires is_container");
  // ...
}

---

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Yep! I guess that works too, thanks!