fxp The Functional XML Parser



o About fxp
o fxp Versions and Changes
o Where to get fxp
o How to install fxp
o Example Applications: fxp, fxcanon, fxcopy, fxesis, and fxviz


What is fxp?

fxp is a validating XML parser written completely in the functional programming language SML. fxp can validate both XML 1.0 and XML 1.1 documents. It has a programming interface allowing for production of XML applications based on fxp. It comes with four example applications:
o fxp, the pure parser. It parses a document and finds well-formedness errors, validity errors and other problems;
o fxcanon produces an equivalent canonical XML document. Canonical XML was invented by James Clark for testing XML parsers. It contains only the information a processor is required to pass to the application; 
o fxcopy reproduces the document parsed by fxp. The copy can be generated in a different encoding than the input, and can be normalized in different ways concerning, e.g., expansion of entity references; 
o fxesis adds a backend to fxp, producing an output similar to nsgmls's ESIS (Element Structure Information Set) output;
o fxviz is an XML tree visualizer. It produces a graph description suitable as input to Georg Sander's vcg
More features of fxp are here.


fxp Versions and Changes

The current version of fxp is 2.0. Changes from the previous versions are described here.


Downloading fxp

The source code for fxp can be downloaded by http. The Copyright note is here.


Installation instructions

In order to install fxp, you need an SML compiler. It has been tested with the stable versions 110.0.7 and 110.0.6 of SML of New Jersey on Linux. For other unices we expect no problems. fxp ports to other SML compilers or other systems are documented here. The compiler must have the compilation manager (CM) built in, which is the default when installing SML-NJ. An installation using the Windows version of SML-NJ is documented here.

These are the steps for installing fxp under Unix:

  1. Download the latest version of fxp;
  2. Unpack the sources, and change to the fxp directory, e.g.:
  3.     gunzip -c fxp-2.0.tar.gz | tar xf -
        cd fxp-2.0
  4. Read the COPYRIGHT;
  5. Edit the Makefile according to your needs. Probably you will only have to change the following:
  6. Edit the file src/config.sml according to your needs. Currently only a single value can be configured here:
  7. Compile fxp by typing make;
  8. Install fxp by typing make install.
  9. If you want to use fxviz, you should also install vcg.

fxp's Programming Interface

Here is a document describinng the programming interface


fxp's feedback address

Any feedback related to fxp is welcome to:



The author of fxp is Andreas Neumann. fxp is maintained and updated by Alexandru Berlea.