[Haskell-cafe] what are the points in pointsfree?

[Andrew Wagner]

Here, I think an examples worth a thousand poi....err, words. This one
comes from YAHT. Consider the two implementations of the following
function:

lcaseLetters :: String -> String
lcaseLetters s = map toLower (filter isAlpha s)

lcaseLetters :: Strint -> String
lcaseLetters = map toLower . filter isAlpha

Both functions will do the exact same thing. The second, however is
written completely in terms of function composition and application.
The s in the first implementation is what's being referred to as a
'point'.

On 12/14/06, Steve Downey <sdowney at gmail.com> wrote:
> i'm not naive enough to think they are the composition function, and
> i've gathered it has something to do with free terms, but beyond that
> i'm not sure. unless it also has something to do with fix points?
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