From: itsme213 <itsme213@...>
Date: 2005-01-07T02:51:31+09:00
Subject: Re: Ruby Data Structure Query Abstractions/Patterns


"Nicholas Van Weerdenburg" <vanweerd@gmail.com> wrote
> > > > (1) Having a uniform and extensible concrete syntax for tree
structures
> > is
> > > > great
> > > > (2) Having a whole set of uniform manipulations on (1) is great
> > > > (3) Insisting on applying (1) to the concrete syntax of (2) is
absurd
> > and
> > > > the result, ugly
> > >
> > > I don't know what (3) is talking about. The syntax of XPath isn't XML.
> > > It's a domain-specific language inside XML, much as regexs are a
> > > domain-specific language inside ruby.
> >
> > Well, my analogy to writing Ruby was off the mark, but I suppose I was
doing
> > my rant to your "what's not to like about XML" rant. Because (3) is
> > definitely something I dislike about the XML (and it sounds like you
would
> > agree too).
> >
> >
>
> I had trouble understanding point 3, but I'm guessing your point was
> that XSLT shouldn't be an XML dialect, but rather a proper language?

Roughly yes. Specifically I thought the designers really failed to separate:

- the conceptual model of each language (the abstract syntax graph, or
roughly the AST with all cross-tree references resolved into edges and with
its static well-formedness rules plus semantics of what a given abstract
graph actually means e.g. when executed); XML is quite inadequate for this.

- the concrete interchange syntax of the language (for which an XML dialect
typically works fine); and

- the concrete human syntax(es) of the language, whether text or graphical;
XML is typically awful for this;

- the mappings between these (e.g. more than one possible XML encoding of an
abstract syntax)

In the case of XSLT they went further and designed a very low S/N-ratio
pointy-bracket concrete syntax for an untyped language that used some
unconventional combination of functional and rule-based features to
transform statically typed data. It's a good thing XQuery backed away from
some of that earlier unbridled XML enthusiasm. And I'm sure there is a pent
up rant in there somewhere...:-)