Comments on: Kid’s play with HTML in Haskell

By: fritz

fritz — Tue, 01 Apr 2008 17:28:10 +0000

All this and a bonus: the code upgrades easily to retrieve broadcasts made in the late afternoon!

isMp3Link = (==) “3pm.” . take 4 . reverse

Just take away that reverse … .

(Sorry, April 1st for me, couldn’t resist the “3pm” part ).

By: Neil Mitchell

Neil Mitchell — Sun, 30 Mar 2008 22:30:50 +0000

@Magnus, I decided to write it up as a post on my blog, http://neilmitchell.blogspot.com/2008/03/toddlers-play-with-html-in-haskell.html

HXT certainly does a lot more than TagSoup does, but for the simple cases (like this one), I find TagSoup tends to be shorter and a bit clearer.

By: Magnus

Magnus — Sun, 30 Mar 2008 22:22:56 +0000

@Neil,

Nice. I've never looked at tagsoup so it's nice to see some code using it. One nice thing with HXT is that it handles both URLs and files without any extra work by me. Though I think your code above is a bit more “intuitive”, at least for someone like me who doesn't have a lot of previous exposure to arrows.

By: Neil Mitchell

Neil Mitchell — Sun, 30 Mar 2008 22:16:06 +0000

Instead of using HXT, you can do this directly in TagSoup:

import System.FilePath import System.Environment import Text.HTML.TagSoup

main = do [src] <- getArgs txt <- readFile src mapM_ putStrLn [mp3 | TagOpen "a" atts <- parseTags txt, ("href",mp3) <- atts, takeExtension mp3 == ".mp3"]

I've also used System.FilePath to check if an extension is mp3