[Haskell] Broken monad laws

[Sean Seefried]

On 24/11/2005, at 9:45 AM, Iavor Diatchki wrote:

> Hello,
> I just noticed that the GHC/Hugs "standard" libraries have acquired a
> list monad transformer, which is broken, because it does not satisfy
> the associativity law when applied to non-commutative monads.  I am
> not referring to some corner-case strictness problem, but rather a
> fairly well known result.  The associativity law is important, because
> without it the 'do' notation can be very confusing.  Bellow is an
> example, for people not familiar with the porblem.
> -Iavor

This seems to have been discussed already:

http://haskell.cs.yale.edu/hawiki/ListTDoneRight

Sean