IdentityT to transformers

[Ross Paterson]

On Thu, Feb 12, 2009 at 08:06:30PM +0100, Henning Thielemann wrote:
>
> On Thu, 12 Feb 2009, Henning Thielemann wrote:
>
>> Unfortunately I have just another wish. In a parser I like to show by 
>> types whether the parser can fail or not. To this end I have a type 
>> parameter for a monad transformer that can be instantiated either by 
>> MaybeT or by IdentityT. The only problem is, that there is no IdentityT 
>> in transformers package, yet.
>
> Does the attached module makes sense?

I've already got Magnus Therning's from his blog.