Re: [Haskell-cafe] Monads, do and strictness

21 Jan 2012


      On Sat, Jan 21, 2012 at 11:08 AM, Roman Cheplyaka  wrote:
...
* David Barbour  [2012-01-21 11:02:40-0800]
...
On Sat, Jan 21, 2012 at 10:51 AM, David Menendez 
wrote:
...
The Eval monad has the property: return undefined >>= const e = e.
You can't write `const e` in the Eval monad.
Why not?
ghci> runEval $ return undefined >>= const (return ())
()
It is, at the very least, utterly pointless to have an Eval monad with
`const`.

Regards,

Dave