[Haskell-cafe] Paths to tree

[Bulat Ziganshin]

Hello John,

Tuesday, January 30, 2007, 2:57:04 PM, you wrote:

>     mergeForest2 =
>         map pairToNode .
>         Map.toList .
>         Map.map mergeForest2 .
>         Map.fromListWith (++) .
>         map nodeToPair

> My problem I guess is being able to write the code this way when
> the need arises or even just recognising when and where it's an
> option, both of which to me is considerably harder.

i guess that it's just imperative style of thought that you can't
easily scrap out. the whole idea of functional programming is that you
make data *transformations*. you start with one data representation,
then transform it into another, then you can make some
sub-transformations with sub-elements of your data (using various "map"s),
then you may glue data together using various folds and so on. there
are real difference between imperative style do-it-after-that and
functional style "map original data into result"

btw, are you seen http://haskell.org/haskellwiki/Simple_unix_tools ? :)


-- 
Best regards,
 Bulat                            mailto:Bulat.Ziganshin at gmail.com