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

[jerzy.karczmarczuk at info.unicaen.fr]

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. 


Jerzy Karczmarczuk