"Yitzchak Gale"
Jon Fairbairn wrote:
... or, "whoops! I've writtten another html combinator library." History: I was surprised to find that all the Haskell html generating stuff I've tried allowed one to construct invalid HTML...
This is a wonderful idea, and it is clear that you have done some serious work here.
Thanks. It certainly felt that way... in case anyone reading my announcement thought otherwise, the library is pretty much complete, but there are a few design decisions that need more heads than just my own. [I've thought of another one: should I group together the prohibited elements corresponding to %pre.exclusion, %formctrl (in the html dtd) to reduce the number of type arguments?]
I'm announcing it here because I hope the audience is fairly small but discerning
I believe that the audience could be large. As for discerning, that remains to be seen. :)
:-) Well, I mean here on the libraries list. If I get some feedback from here I'll announce it on one of the other Haskell lists.
What you are doing here is enforcing a DTD using the Haskell type system. Apart from your plans for HTML 4.01, perhaps a better generalization would be to generate typeful combinators that could validate at compile time for any given XML DTD.
I think that would be the job of something like HaXml or HXT, and there are plenty of good people working on them. To clarify, what these types enforce is something stronger than an XML DTD, more like the SGML DTD of html (and as I write this I am inclining myself further towards making the document tree types fit the common subset); it enforces the restrictions that are only expressed in prose in the xhtml1.0 standard. You could think of it as enforcing a schema (that the w3c didn't provide). The reason for wanting to produce HTML4.01 is that it's widely understood by current browsers, and serving xhtml as html is (IMHO) rather questionable (the sets of attributes aren't the same for one thing). I only started with xhtml because I could use HaXml to get it off the ground. As to other future work, I'm more inclined to try to push typefulness out into other libraries that this one could use, such as Network.URI. -- Jón Fairbairn Jon.Fairbairn@cl.cam.ac.uk