[Haskell-cafe] Are there standard idioms for lazy,
pure error handling?
ketil at malde.org
Thu Dec 3 06:34:05 EST 2009
Duncan Coutts <duncan.coutts at googlemail.com> writes:
>>  http://hackage.haskell.org/package/failable-list
I agree this is needed (or rather, would be nice to standardise).
Although I don't care for the cutesy naming suggested in the 'Train'
datatype, failable-list could be made more general. Why is there a
specific constructor 'Done', instead of just allowing the user to select
a value of type 'e' (using 'Maybe b' if nothing else works)?
Perhaps we could also consider an infix notation, like:
data TerminatedList a e = Then a (TerminatedList a e)
| Finally e
(So you could do e.g: 4 `Then` 5 `Then` 1 `Finally` "success!". Of
course, you might prefer symbols instead.)
If I haven't seen further, it is by standing in the footprints of giants
More information about the Haskell-Cafe