Dark Corners
============

_this page accounts for some problematic areas, sketchy solutions,
nonportable hacks, terrorism and other misdemeanour_

Library
-------

Binding Placeholders
~~~~~~~~~~~~~~~~~~~~
The standard allows function objects to be partially closed; this is achieved by
marking the remaining, unbound arguments in the call to `std::bind` with some special
_marker elements_, the ``argument placeholders''. These are predefined within the
standard library as `std::placeholders::_1` and consecutive, while the _type_ of
these objects remains _unspecified_ as by the standard. But unfortunately we need
some augmentation on top of `std::bind` to help with _generic partial application_
of functions, i.e. we need to close systematically a sequence of arguments, both
starting from the front or from the back of the argument list. We need this,
because it is a standard functional programming technique. Consequently
our helper (`function-closure.hpp`) will build placeholders on its own,
and it needs to feed _placeholder types_ to the generated binders.

Thus we rely on the fact, that the gnu standard library implementation
has a templated type `std::_Placeholder<i>`



Size of standard library facilities
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Sometimes we need to know the size of an STL or Boost class, but can't afford
to include the header and just write a `sizeof()`. Because including some of those
headers incurs quite some price in terms of compilation time and even size of the
debug executable.

Obviously, a simple solution would be to measure those sizes and hardcode them.
But what about portability? To get out of that dilemma, I created a traits class
which mimics the implementation memory layout of those facilities in question,
simplified as much as possible. As long as the GNU libstdc++ or Boost don't
change their implementation layout, this give us precise and fast size bounds.

When relying on that hack, we should make sure always to place some kind of
`static_assert` into the corresponding implementation files to ensure the real
facilites actually _do fit_ into the guessed storage dimensions.

