Re: [Haskell-cafe] Questions about the Functor class and it's use in "Data types à la carte"

[Jules Bean]

jerzy.karczmarczuk at info.unicaen.fr wrote:
> Roberto Zunino writes:
>> without seq, there is no way to distinguish between undefined and (const
>> undefined), 
> 
> "no way to distinguish" is perhaps too strong. They have slightly
> different types.

At a particular type which they both inhabit, such as (a->b) or, to be 
concrete, (Int -> Int), there is no way to distinguish without seq.

Jules