Library to facilitate the use of the “design by contract” principle [closed]

Answer 1

If you don't mind using C++0x features, you could implement preconditions and postconditions using lambdas and RAII.

A simple example of postcondition:

struct __call_on_destructor {
  std::tr1::function<void()> _function;
  template<class Func> inline __call_on_destructor(Func func) {
      _function = func;
  }
  inline ~__call_on_destructor() {
      _function();
  }
};

#define on_scope_exit(function) \
  __call_on_destructor PP_UNIQUE_LABEL(on_exit) (function)

#define ensures(expression) \
  on_scope_exit([&] () { assert(expression); })

Similarly, you could implement preconditions and invariants. The code was taken from an extremely simple C++0x Contracts library.