Installing on Windows
Follow SkyTreeBird's guide. It which walks you through the basic steps
- setting up environment variables
cabal install wx
Note that the best way to refer to WxWidgets in your PATH is probably to use the WXWIN variable that you set, eg.
The guide has been tested with the following configurations:
Building your own wxWidgets (optional)
Note: Microsoft compilers are no longer supported. The cabal build system cannot understand the output of wx-config for Microsoft compilers.
Note: The Haskell Platform 2010.1.0.0 installer shipped without C++ support. If you want to build wxHaskell on Windows using this Haskell Platform, please see 
Using the MSYS shell, and making sure that you have the C++ compiler option installed for MinGW as it is 'not' the default:
> cd /c/path/to/wxWidgets-2.8.10/build/msw > mingw32-make -f makefile.gcc BUILD=release MONOLITHIC=1 SHARED=1 UNICODE=1
This will take quite some time and generate lots of text in the MSYS shell. Assuming it is successful, a DLL is generated in /c/path/to/wxWidgets/gcc_dll, which you will need to copy to a location where it can be found when running your executables.