[Haskell-beginners] Re: Closure

[Daniel Bastos]

In article <20090729202442.GA8017 at seas.upenn.edu>,
Brent Yorgey wrote:

> With that said, on some level the idea of a closure is really just an
> implementation detail---I wouldn't say that understanding it is of
> fundamental importance in learning Haskell.  But learning things never
> hurts (except when it does).

So it sounds correct to say that a closure is a function that brings
an environment with it, such as variables defined outside of it. 

With this ability, we can construct functions on the fly because a
function can return a closure which is amended and, say, returned
again another closure more fully specified.