Install the Haskell Platform.
cabal update && cabal install texmath -fexecutable
texmath --help
If installation succeeds but texmath is not found,
make sure your system PATH includes the cabal bindir, which by
default is ~/.cabal on linux
and ~/Library/Haskell/bin on Mac OS X.
If you want to use texmath as a Haskell library, see the API documentation.