Replace deprecated binder2nd and binder1st

[phcerdan]

binder2nd generates error in c++17

Replace by lambdas when possible and with std::function when the type is
required.

decltype(lambda) does not work, so we bind the lambda to a std::function.

Other option also used is std::bind and std::placeholders.

FIX #1221

Checklist

• [NA] Unit-test of your feature with Catch.
• [NA] Doxygen documentation of the code completed (classes, methods, types, members...)
• [NA] Documentation module page added or updated.
• New entry in the ChangeLog.md added.
• No warning raised in Debug cmake mode (otherwise, Travis C.I. will fail).
• All continuous integration tests pass (Travis & appveyor)

[rolanddenis]

Thanks !

In fact, we can make a decltype on an already-existing lambda but compilation will fail due to the Functor concept in DGtal that except a functor to be assignable. Since a lambda is not assignable, I agree that using std::function is the best way !

There is still one std::binder1st left in DGtal/graph/DistanceBreadthFirstVisitor.h

[rolanddenis]

You can also simply pass v by const-ref and test v == 1. In fact, using && here forbids lvalue parameters, like in the code

const auto fn = [] ( int&& v ) { return v == 1; };
int a = 3;
bool dummy = fn(a);

Here, since the std::function signature specifies a pass-by-value parameter, it doesn't fail.

Therefore, I also suggest to use a std::function<bool(Image::Value const&)>.

[phcerdan]

Ahh, makes sense, still rusty with std::forward usage. I will change it in 12 hours

[phcerdan]

Good points, I will polish it tomorrow morning, thanks!

[dcoeurjo]

(tagged as 0.9.4)

[phcerdan]

I have changed the signature of std::function as @rolanddenis suggested.

Replaced binder1st with std::function, and its instantiation, using std::bind1st, with a std::bind and std::placeholder.

[rolanddenis]

Thanks !
I have also removed useless boost/bind.hpp includes.

[dcoeurjo]

thanks @phcerdan & @rolanddenis

Merging..