[review] possible bug

[DaMilyutin]

in include/pipes/base.hpp there is
struct pipeline_base : detail::crtp<Derived, pipeline_base>
{
...
Derived& operator++() { return this->derived(); } // should here be ++this->derived();
... };

[joboccara]

Thanks for bringing this up.
This is supposed to be intentional, as the derived class don't have an operator++. The point of having the base class have one is to make the code of STL algorithms compile, while all the work is done by the operator=.