Editing CamHac/PostHackathonReport (section)

== Implementing 'docase' notation in GHC ==

I (Tomas Petricek) started implementing the <hask>docase</hask> notation that I briefly presented on Sunday as a GHC langauge extension. The slides from the presentation [http://slidesha.re/oJP10b are available online] and you can find more information in my [http://www.cl.cam.ac.uk/~tp322/papers/docase.html Haskell Symposium paper].<br /><br />
At Hasckathon, I extended the GHC lexer & parser and added a language extension flag <Hask>DocaseNotation</Hask>. I also understood a little bit how type-checker and desugaring works and I got a very basic part of the extension to work (one particular part of syntax type-checks and desugars to Prelude function call, but it supports re-bindable syntax as other similar extensions). I continue working on the extension and will upload a patch for more discussion when it's ready.