[Haskell-beginners] Sidebar to variables

[Thomas Davie]

On 25 Jul 2009, at 15:42, Duke Normandin wrote:

> My recent questions concerning "variables" spawned this observation:
>
> I take it that programming a solution using a functional language like
> Haskell is really about "linking" a series of functions from which a
> solution is derived.
>
> It seems to me that this approach would naturally encourage the use of
> the "bottom-up" method of program development. I mean, breaking the
> task down to the smallest possible segments, and then writing a  
> function
> for each segment. Refactoring the task until the smallest segments are
> achieved. Very much like what I learned about programming in Forth  
> (they
> use the term "words" to mean "function")
>
> Am I on the right track here, in my view of the "Haskell approach" to
> programming solutions?

I'm not sure -- bottom up is certainly something useful, but top down  
can still be done.  I often write programs like this:

bigFunction :: a -> b -> c
bigFunction = undefined

<thinks>

bigFunction x = smallerFunction . otherFunction x . anotherFunction

smallerFunction :: a -> b
smallerFunction = undefined

otherFunction :: a -> b -> c
otherFunction = undefined

anotherFunction :: a -> b
anotherFunction = undefined

<thinks>

(repeat the process until no more undefineds)

Bob