Ask YC: if Haskell is the hammer, what should be the nail?

I've just started watching the Simon Peyton Jones videos on the subject (from OSCon last year), and I've been kinda thinking I might tackle some systems monitoring problems (I usually use Perl for that sort of thing...and most every other sort of thing, lately). I, too, have been struck a bit by how low-level most of the libraries and such are, at this point (then again, compared to CPAN almost every language has a dearth of high level libraries). And I'm still far too much of an amateur at the language to do much about it. But it is an interesting language, and probably useful to tinker with even if no useful code ever comes of it.

Right now, the area Haskell absolutely thrashes everything else is speedy and lightweight concurrency (it even stomps Erlang in the Debian Shootout). So if you can find a project that needs fluid responsiveness, multi-connection or or multi-CPU scaling, Haskell is the ideal tool.

Personally, I think there are some very interesting possibilities for using Haskell in the highly-secure web application space. The most trivial example would be simply using the type checker to protect against SQL injection and cross-site scripting attacks by representing user input with a different type than query parameters or HTML output.<p>I've also thought for a while that Haskell would be a great environment in which to implement a static analysis tool to check the security of existing application code. In particular, I think that the PHP community could really use an information-flow and type-checking tool external to the core runtime which could be used to run a quick "sanity check" over source code. The simplicity of the language (relative to, say, Ruby or Perl) makes it a prime target for parsing and analysis, and the large body of existing code in the wild makes for an interesting set of test cases.

what isn't haskell for?<p>i've been throwing it at everything from fastcgi programs to scrapers to scripting to systems stuff<p>maybe the one place it isn't well suited is in the realm of throw-away quickies. haskell code takes longer to write. that doesn't mean you are writing a lot of code. i still see a role for perl/python in throaway scripts<p>haskell has practically every meaningful cool concept in CS built in. it is <i>the</i> functional language (for now). it is very fast and as the number of cores rises, haskell's performance will start to leave traditional tools in the dust. with the new GC it will destroy erlang on its own turf.<p>haskell takes time to learn and time to code. if you are in a rush, it is not for you. otherwise, haskell can handle almost any problem<p>in any case, you can come to haskell or it can come to you. the next ten years will see functional concepts get weaved into every language.