XDuce: A Typed XML Processing Language

Overview

   XDuce ("transduce") is a typed programming language that is
   specifically designed for processing XML data. One can read an XML
   document as an XDuce value, extract information from it or convert it
   to another format, and write out the result value as an XML document.
   Since XDuce is statically typed, XDuce programs never crash at run
   time and the resulting XML documents always conform specified types.

   XDuce has several notable features.
    1. Regular expression types, which are similar in spirit to Document
       Type Definitions (DTD).
    2. A powerful notion of subtyping. (It allows any subtyping relation
       that you may expect from your intuition on inclusion relation of
       regular expressions.) It not only gives substantial flexibility in
       programming, but also is useful for schema evolution or
       integration.
    3. Regular expression pattern matching. In addition to ML-like
       patterns, we can match values against regular expression types.
    4. Attribute types in the style of RELAX NG. We can mix both
       attribute constraints and element constraints in the same regular
       expression notation.
    5. Regular expression filters, an extension of pattern matching where
       we can form a regular expression over pattern clauses.
    6. Parametric polymorphism.

Implementation Status

   This implementation is a part of our ongoing research. The language
   design has not been finished, and some algorithmic issues in type
   checking and the run-time system still remain. This language system is
   likely to be drastically changed in near future. So please do not
   depend on this software. On the other hand, any comments and
   suggestions are welcome!

System Requirements

   XDuce system is solely written in [1]the O'Caml language. In
   principle, XDuce should run on any platform that O'Caml supports. In
   particular, we have checked that XDuce works on the following.
     * SunOS 5.7
     * Intel Linux
     * LinuxPPC
     * IRIX
     * Mac OS X

   We have not yet tested compilation on Windows. However, since recent
   versions of O'Caml and the libraries that XDuce depends on support
   Windoes with Cygwin, XDuce should work on this platform in principle.

Building XDuce

    1. Make sure that GNU make or its equivalent is installed.
    2. Install [2]O'Caml (newer than 3.04; older ones may not work) if
       not yet installed.
    3. Install the [3]findlib tool (newer than 0.6.2).
    4. Install the following libraries in this order.
         a. [4]netstring (newer than 0.10.1)
         b. [5]PXP (newer than 1.1.3)
       Note: You have to build each library by typing "make opt" in order
       to build xduce by the native O'Caml compiler (type "make all" if
       you want to compile the bytecode version of xduce).
       Note: You can also install all the above software by using [6]GODI
       (package manager for O'Caml libraries). In this case, replace
       netstring with ocamlnet.
    5. Compile XDuce as follows.
         a. tar xvfz xduce-xxx.tar.gz (where xxx is the version number of
            XDuce you downloaded).
         b. cd xduce-xxx
         c. make
       It will produce an executable file named xduce.opt in the
       xduce-xxx directory.
       On platforms where native O'Caml compiler is not supported, still
       bytecode version may work. For this compilation, type:

     make debug
       This will yield an executable file xduce. The usage is the same.
    6. At the moment, we do not provide any automatic installation
       mechanism. You may move the executable wherever you want. Note,
       however, it directly refers to the xduce-xxx/lib directory. Make
       sure that this directory is accessible when you use the
       executable. Or, if you need to move the lib directory, then
       specify the new location by -path option:

     xduce.opt -path <new-location> ...

Usage

   type

     xduce.opt <XDuce program file>

   to run a XDuce program. Type

     xduce.opt -help

   to see options.

Documentation

   There is no user's manual since the language design is not yet
   settled. The programs found in "examples" directory would be useful
   for understanding the language. Also, the files in "lib" directory
   (such as "pervasive.q" and "xml.q") would be worth seeing.

   For more information, visit our web page:

     [7]http://xduce.sourceforge.net

   It also provides some technical papers.

Contact

   Haruo Hosoya ([email protected])

Acknowledgement

     * We especially thank Volker Renneberg for his tremendous
       contributions to our implementation in bug reports, suggestions,
       and additional code.
     * Some sources files from the bibtex2html tool by Jean-Christophe
       Filliatre and Claude Marche are incorporated (in bibtex
       directory).
     _________________________________________________________________

   $Id: README,v 1.7 2005/04/06 07:07:32 hahosoya Exp $

References

   1. http://caml.inria.fr/ocaml/distrib.html
   2. http://caml.inria.fr/ocaml/distrib.html
   3. http://www.ocaml-programming.de/packages/documentation/findlib/
   4. http://www.ocaml-programming.de/packages/documentation/netstring
   5. http://www.ocaml-programming.de/packages/documentation/pxp
   6. http://godi.ocaml-programming.de/
   7. http://xduce.sourceforge.net/