On 2/1/07, Al Falloon
Boost.Python is for extending Python with C++, or embedding Python in C++. This is especially useful because it allows you to use Python as an extension language for a C++ program.
Presumably Boost.Haskell would be for integrating Haskell code with C++, which would of course be useful, but the main use case (an embedded extension language) that draws people to Boost.Python isn't as much of a draw for Haskell because of the compilation phase.
On the other hand, I suppose you could always integrate a Haskell interpreter like Hugs, or even go the HsPlugins route and dynamically load a compiled module, but the fit doesn't seem as natural as it does with a latently typed scripting language.
There are also technical problems that are hard to overcome. Extending Python is mostly done in C, so a C++ library to add some nice sugar is a good fit. Haskell, OTOH, embeds C programs via its FFI. There doesn't seem to be any way to export functions and value from C++ to Haskell, but instead the C++ code must import from Haskell. All the heavy lifting is done on the Haskell side, so there isn't as much opportunity to write a slick C++ library.
This could change if someone made a version of Hugs that can be linked in as a library with a documented C API for evaluating Haskell code and mucking with Haskell values. But I don't think its much of a priority right now :)
-- Alan Falloon
I think a more common scenario would be using C++ legacy code in Haskell project. I would imagine Boost.Haskell as collection of code generation templates for exposing C++ APIs to be used in Haskell. That would be sweet. Even sweeter is easily accessing .Net Framework from ghc, especially for Windows users. .Net Framework is huge. It is de-facto _the_ windows framework. Are there any projects going in this direction? -- Slavomir Kaslev