Excerpts from Jose Iborra's message of Sun Nov 29 10:41:50 -0500 2009:
There is indeed an Monad instance for Either in mtl,
declared in the module Control.Monad.Error.
I can't explain why your compiler cannot find it.
Can you paste a blurb of code somewhere?
{-# LANGUAGE PackageImports,
On 28/11/2009, at 22:08, Edward Z. Yang wrote:
Hello folks,
I took advantage of Thanksgiving weekend to port my application to use
Control.Monad.Failure, and learned (slightly painfully) that I still
needed to pick some mechanism to instantiate my failure monads as.
After the experience,
Hello folks,
I took advantage of Thanksgiving weekend to port my application to use
Control.Monad.Failure, and learned (slightly painfully) that I still
needed to pick some mechanism to instantiate my failure monads as.
After the experience, I have three questions/comments:
1. Why isn't there an
