Description

A prototype for evaluating Xcerpt programs is developed actively at the universities of Munich and Linköping. The prototype is implemented in the functional programming language Haskell and supports most of the language features described here (except negation). Since this is a development version not intended for production use, expect the prototype to contain many bugs. Although performance is not a priority in the development, Xcerpt programs are now evaluated with reasonable speed that compares to prototypical implentations of XQuery.

Demos

Xcerpt Online Demo

An online version of the Xcerpt-prototype can be found at http://demo.xcerpt.org. Xcerpt programs can be evaluated using a CGI evaluator written in Haskell. Please read the provided documentation carefully. The prototype is currently considered experimental but should work in most cases.

visXcerpt Online Demo

Besides the online version of the text-based Xcerpt prototype, there is also a prototypical implementation of visXcerpt, the visual rendering of Xcerpt. visXcerpt allows to compose and evaluate queries using a visual interface which is intended to be much easier to comprehend for novice users. The visXcerpt prototype can be tried out online at http://visxcerpt.xcerpt.org.

Getting the Code ...

The source of the prototype is available for free under the GNU General Public License. We encourage you to experiment with the code and give us some feedback. If you have bug fixes or other contributions, feel free to send an email to mailto:schaffert@xcerpt.org

Releases

Working releases (binary and source) of the prototype are made available in regular intervals at Xcerpt's SourceForge Project Site. If you merely want to try out Xcerpt, this is the place to go.

Development Snapshot

Current versions of the prototype are available through a Subversion repository. Beware that these are development versions and thus sometimes break! You can access the latest snapshot by using the following commands (on Unix):

svn co http://cvs.wastl.net/Xcerpt

If you already have a local copy of the code, switch to that directory and simply issue:

svn update

Source Compilation

Compilation of the Xcerpt source code currently only works flawlessly on Unix. Instructions for building on Windows will be provided in the near future.

Unix

To build the source code, you need at least the following software:

• GNU make
• The Glasgow Haskell Compiler (ghc), version 5.02 or later (5.04.3 recommended)

If you plan to do modifications to the parser or lexer, you will in addition need the following tools:

• happy (the Haskell Parser Generator)
• alex (Haskell Lexer Generator)

The source package also contains experimental code for interfacing with the Xcerpt prototype from foreign programming languages. At the moment, C, Java, and Python are supported. For building foreign language interfaces, you need to have the following (in addition to the tools above):

• a development environment for that language (i.e. GCC, JDK, Python headers)
• swig (an interface generator for scripting languages)

Building the source should then be as simple as

cd Xcerpt
make

When compilation finishes, you should find two binaries called xcerpt and convert in the directory.

Bug Reporting

Please use the bugtracking system at SourceForge to report bugs. This allows us to have a more centralized management of bugs.