[Haskell-cafe] Call for comments: neither package

Jeremy Shaw jeremy at n-heptane.com
Tue Jun 29 15:56:18 EDT 2010

On Jun 29, 2010, at 6:02 AM, Stephen Tetley wrote:

> 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 applicatives-extra package defines a type:

type ErrorMsg = String
data Failing a = Failure [ErrorMsg] | Success a

Which is a less general version of that type.

I am fine with the more general version, but we should make sure that  
applicative-extras and things which depend on it are updated, so that  
we don't have a bunch of really similar types floating around.

- jeremy

More information about the Haskell-Cafe mailing list