"S. Alexander Jacobson" <[EMAIL PROTECTED]> writes:
> There is a campaign going on to separate XSL (eXtensible style
> language) into two separate languages
> 1. a transformation language
> 2. a style language
>
> I suggest that now is the opportunity to make a convincing case that the
> transformational language should be a functional programming language.
> HoF, Laziness and statelessness are ideal properties for such a language.
> The existing XSL spec was somewhat influenced by scheme, but a
> transformational language has stronger consistency requirements and should
> be typechecked so Haskell seems like a good choice.
I have bad news, good news, bad news, and good news.
Bad news: The proposal to split XSL refers to the current working
draft, which already contains a transformation language (Section 2)
and a style language (Section 3). Preliminary versions of the
transformation language are already in wide use (including Internet
Explorer 5 by Microsoft; LotusXSL by IBM Alphaworks; and xt, by James
Clark, editor of the XSL document). So it's way too late, there is no
chance of getting the W3C to switch to Haskell.
Good news: The charter requires that XSL be `a declarative language',
and in fact the transformation part of XSL is a functional language.
It is largely based on DSSSL, the stylesheet language for SGML, an ISO
standard based on Scheme. (I was gobsmacked when I first discovered
Scheme was part of an ISO standard for document production!)
Bad news: XSL is not nearly as nice as Haskell. Sigh.
Good news: Malcolm Wallace and Colin Runciman at York are working
on a Haskell library for manipulating XML. If the transformation and
style languages are separated (which seems likely to happen), then that
will make it easier for users to substitute Haskell for the transformation
part of XSL, if they choose.
-- Phil Wadler (member of the XSL working group)
PS. If anyone has any suggestions about *small and reasonable* changes
to the XSL working draft that would be an improvement, please let me know.
XSL working draft: http://www.w3.org/TR/WD-xsl
XSL W3C home page: http://www.w3.org/Style/XSL/
-----------------------------------------------------------------------
Philip Wadler [EMAIL PROTECTED]
Bell Labs, Lucent Technologies http://www.cs.bell-labs.com/~wadler
600 Mountain Ave, room 2T-402 office: +1 908 582 4004
Murray Hill, NJ 07974-0636 fax: +1 908 582 5857
USA home: +1 908 626 9252
-----------------------------------------------------------------------
