Call Haskell from C (not C++) seems pretty easy:
- [Calling Haskell from C - HaskellWiki](https://wiki.haskell.org/Calling_Haskell_from_C)
And the FAQ on the Haskell wiki directly addresses this too:
- https://wiki.haskell.org/Introduction#I_already_have_a_large....
So apparently it is doable!