Fw: Language is not markup and markup is not language.

["Larry Fitzpatrick" <lef@xxxxxxxxxxxx>]

Oops. that last message slipped before I finished it (keyboard stutter).

I'm hoping that someone with expertise in this area could comment.

>Dave LeBlanc
> I received a private post from someone asserting that xslt's language seems
> to have it's roots in "tree transformation languages". Seems to me that
> most general purpose languages are pretty adept at tree manipulations - and
> a host of other useful things as well.

Came across the following references to tree transformation languages which
seem to indicate some advantages to approaching the problem of transformation
this way. In particular (from below), note:
    "TT-grammars assure that the constructed transformation will produce only syntactically correct output even
    if the source and the target representations may be specified with two unrelated context-free grammars. "
and
    "TranSID does not require the user to specify a grammar for the target representation but instead gives full
    programming power for arbitrary tree modifications. "

I don't think that the same can be said for tree transformation in procedural (general purpose?) programming
languages.

Cheers!lef

In particular see:

> http://www.oasis-open.org./cover/bib-il.html
>
> Jaakkola, Jani; Kilpeläinen, Pekka; Lindén, Greger. TranSID: An SGML Tree Transformation Language. Department of Computer Science,
> University of Helsinki Report C-1997-36. Helsinki, Finland: University of Helsinki, Department of Computer Science, May 1997.
> Extent: 14 pages (with 15 references). Authors' affiliation: Department of Computer Science, University of Helsinki.
> Abstract: "We present a powerful document transformation language called TranSID, which is targeted at structured (SGML)
documents.
> The language is based on a powerful model where the entire input document tree may be referenced during the transformation
process.
> The evaluation is performed in a bottom-up manner. A language evaluator has been implemented which runs in Unix environments."
>
>
> Lindén, Greger. Structured Document Transformations. PhD Thesis. Report [Series of Publications] A-1997-2. Helsinki, Finland:
> Department of Computer Science, University of Helsinki, June 1997. Extent: 122 pages (bibliography: pages 109-122). ISBN:
> 951-45-7766-3. ISSN: 1238-8645. Author's affiliation: Department of Computer Science, P. O. Box 26 (Industrigatan 23), FIN-00014
> University of Helsinki, FINLAND; Tel: +358 9 708 44164; FAX: +358 9 708 44441; Email: Greger.Linden@xxxxxxxxxxxxxx; WWW:
> http://www.cs.helsinki.fi/~linden/.
> Abstract: "We present two techniques for transforming structured documents. The first technique, called TT-grammars, is based on
> earlier work by Keller et al., and has been extended to fit structured documents. TT-grammars assure that the constructed
> transformation will produce only syntactically correct output even if the source and the target representations may be specified
> with two unrelated context-free grammars. We present a transformation generator called ALCHEMIST which is based on TT-grammars.
> ALCHEMIST has been extended with semantic actions in order to make it possible to build full scale transformations. ALCHEMIST has
> been extensively used in a large software project for building a bridge between two development environents.
>
> The second technique is a tree transformation method especially targeted at SGML documents. The technique employs a transformation
> language called TranSID, which is a declarative, high-level tree transformation language. TranSID does not require the user to
> specify a grammar for the target representation but instead gives full programming power for arbitrary tree modifications. Both
> ALCHEMIST and TranSID are fully operational on UNIX platforms."
>
> http://www.w3.org/TR/NOTE-stts2.html.en
>
> http://archie.inesc.pt/free-dir/free-S-1.299.html
> TXL is a language for performing source to source transformations and is well suited for rapidly prototyping new languages and
> language processors. It has also been used to prototype specification languages, command languages, and more traditional program
> transformation tasks such as constant folding, type inference, source optimization and reverse engineering. TXL takes as input an
> arbitrary context-free grammar in extended BNF-like notation, and a set of show-by-example transformation rules to be applied to
> inputs parsed using the grammar. TXL is a functional/rule-based hybrid programming language, using the paradigm of structural
> transformation.
>



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