[Haskell-cafe] Category Theory woes

[Alexander Solla]

On Feb 18, 2010, at 1:28 PM, Hans Aberg wrote:

> It is a powerful concept. I think of a function closure as what one  
> gets when adding all an expression binds to, though I'm not sure  
> that is why it is called a closure.

Its because a monadic morphism into the same type carrying around data  
is a closure operator on the type.  It's basically a direct sum of the  
"inner" type, and the "data" type.