[Haskell-cafe] Call for comments: neither package

Stephen Tetley stephen.tetley at gmail.com
Tue Jun 29 07:02:45 EDT 2010

Hi Michael

Good names are a problem of course.

The "Applicative Programming with Effects Paper" has the "monodial
accumulating" applicative instance on a sum type Conor McBride and
Ross Paterson call Except:

data Except err a = OK a | Failed err

The names are nice and to the point, but they would equally describes
the other exception model (monadic - exit on first fail) and having
both might be particularly confusing to newcomers: two error types -
one with an obvious name, one with an unfamiliar one, the unfamiliar
one might be the one they need most often...

Sum might be a candidate, were it not already taken as a type name by

data Sum e a = ??? e | Result a

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