On 9/15/16 4:19 PM, Harendra Kumar wrote:

How about cabal-install using the YAML format as hpack has proven that it works very well for expressing the existing .cabal files? YAML is simple, flexible and open, used across many tools so the knowledge of format is more widely sharable which has its advantages. Are there reasons to keep using the cabal format other than the legacy reasons and the pain of asking everyone to move to another format?

The legacy reasons are important. Haskell has a wonderfully rich software ecosystem, and I wouldn't want to see that ruined by fragmentation.

At the very least, if hpack is going to be supported as an alternative to .cabal files, the support should be implemented in cabal-the-library, not in the front-ends like cabal-install or stack. As long as all the front-ends use cabal-the-library to parse project files, then cabal-the-library can add support for new types of project files (while still keeping support for .cabal files) without risk of fragmentation.

--Patrick