I used to take a look at cabal files from projects that I've used and found to work. For example, IHaskell uses a lot of extensions [1].

[1]: https://github.com/gibiansky/IHaskell/blob/master/ihaskell.cabal#L122-L126

On 9 July 2015 at 21:32, Imants Cekusins <imantc@gmail.com> wrote:

Thank you Sumit.

This is how far I got:

if I put this right after hs-source-dirs:

default-extensions: FlexibleInstances

, it works: ghc asks for MultiParamTypeClasses option.

However if I add FlexibleInstances, MultiParamTypeClasses
- either separated with comma or on the next line, the compiler parses
.cabal and tries to build however prompts for FlexibleInstances again.

How would I specify >1 option?

Regards

Sumit Sahrawat