do and if then else (Ticket 23)

[Jon Fairbairn]

This seems like a good idea, but if it's adopted, I'd argue
that the same thing should be done to case, for consistency.

I like to lay out case like this:

case whatever
of
   blah -> bluh
   blah' -> bluh'

and that also breaks under do. case exp1 [;] of ... would
solve this.

-- 
Jón Fairbairn                              Jon.Fairbairn at cl.cam.ac.uk