Code
Here you can find actual code to download and use, or in some cases license, beg for, etc.
I don't believe in GPL so things here are usually free as in completely unencumbered. If you can't find a download link, it's probably not free, so please email me for details.
Monads in C++
Monads have a deep mystery surrounding them, but they're actually a very simple concept. There is nothing magic here - as a C++ programmer you've probably already done this yourself, or at least seen it done, but probably in a different context. Read more for my explanation of monads for C++ programmers.