ehm. I missed something and ghc api is well documented and stable ?
There are other ways of adding Haskell as a scripting language - bundling ghc is not necessary.
It is inacceptable for scripting language, faced to no-programmers. Such languages must be as plain and regular, as possible.
We give Haskell as a embedded scripting language to non-programmers, and they love it. They especially like the strong typing, which finds their bugs before they ever get the chance to run their script. The terseness and lack of similarity to other programming languages is another benefit. I loved it as well and I was not programmer at that moment. However, I spent about 30-40 evenings to learn it well enough. I wish language,
I still have not found haskell interpreter, that is written in pure haskell and has good quality (i.e. stable, written in stable subset of ghc haskell, is small and so on). I know, that there is haskell-src(-ext), but interpreter (or at least compiler to ext-core) is needed. However, it may be a way... if no other will be found. that can be learned in 3 evenings and used well enough for 3 days of work... And many of it's fetures are not standardized yet.