[Haskell-beginners] Review request

[C K Kashyap]

Thanks Carlos - you can import Text.Regex.Posix to get (=~)
Is there a way to avoid the (++) in your implementation? It has a linear
time overhead.

Regards,
Kashyap

On Mon, Jul 16, 2012 at 1:36 AM, Carlos J. G. Duarte <
carlos.j.g.duarte at gmail.com> wrote:

>  Looks good to me, but I'm just a beginner!
> I used the isInfixOf from Data.List instead of =~ to run your example
> because the later wasn't working on my instalation.
>
> I've made a slightly variant using the break function:
>
> import Data.List
>
> startTag = "<bug>"
> endTag = "</bug>"
>
> main = interact process
>
> process  = unlines . extractSection startTag endTag . lines
> extractSection start stop xs =
>   let (ls,rs) = break (isInfixOf stop) $ dropWhile (not . isInfixOf start)
> xs
>   in ls ++ take 1 rs
>
>
>
> On 07/15/12 13:08, C K Kashyap wrote:
>
> Hi,
> I've written a small haskell program to extract a section from a file
> between start and end markers. For example, if I have a file such as below
> -
>  a
> b
> c
>         <bug>
> d
> e
> f
>         </bug>
> g
> h
> i
>
>  I'd like to extract the contents between <bug> and </bug> (including the
> markers).
>
>  startTag = "<bug>"endTag = "</bug>"
> process  = unlines . specialTakeWhile (f endTag) . dropWhile (f startTag) . lines
>         where f t x = not (x =~ t)
>               specialTakeWhile :: (a -> Bool) -> [a] -> [a]
>               specialTakeWhile ff [] = []
>               specialTakeWhile ff (x:xs) = if ff x then x:(specialTakeWhile ff xs)** else [x]
>
>   It'll be great if I could get some feedback on this.
>
>  Regards,
>
> Kashyap
>
>
>
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