[Haskell-cafe] the trivial monad- thoughts and a question

Isaac Dupree isaacdupree at charter.net
Sat Jan 12 19:34:10 EST 2008


Brian Hurt wrote:
> The second question I have is: is there any hope of getting something 
> like this into the standard library?

the newtype Identity in module Control.Monad.Identity in package `mtl` 
is what you describe:
http://www.haskell.org/ghc/docs/latest/html/libraries/mtl/Control-Monad-Identity.html

in other words, it already is practically in the standard library.

The type-synonym technique doesn't work very well because, e.g., is 
(TrivialMonad (IO ())) ">>=" an IO function or a Trivial function?  It 
has been thoroughly discussed before, IIRC...

~Isaac


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