Here's a clearer description:class Monad m where
return :: a -> m a
(>>=) :: m a -> (a -> m b) -> m b
Instances of Monad must satisfy the following laws:
return a >>= k == k a
m >>= return == m
m >>= (k >>= h) == (m >>= k) >>= h
Much more clear and concise, don't you think?
On Wed, Apr 22, 2009 at 6:21 AM, Daniel Carrera
<daniel.carrera@theingots.org> wrote:
I hate monads.
I love 90% of Haskell. The functional stuff is beautiful, easy to understand, crystal clear, elegant, etc. But I'm having a mighty hard time getting my head around monads. Consider the following explanation of a monad:
"A monad is represented as a type constructor (call it m), a function that builds values of that type (a -> m a), and a function that combines values of that type with computations that produce values of that type to produce a new computation for values of that type".
1) I know what a type is, but not a "type constructor". I don't normally think of an Int or even a complex type as being "constructed" except in the sense of OOP which I know is not what the author means.
2) Just *read* the paragraph... "a type constructor, a function that builds value of that type, and a function that combines values of that type with computations that produce values of that type to produce a computation of values of that type" Ugh....
Can anyone recommend a simple and clear explanation of monads? You can assume that I know basic math and basic Haskell syntax. So, for example, "a -> b" is much more clear than "a function that takes input of one type and has an output of a different type".
Any help would be appreciated.
Daniel.
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