******************************************************************************
Development of PXP
******************************************************************************
==============================================================================
PXP
==============================================================================
PXP is a validating parser for XML-1.0 which has been written entirely in
Objective Caml. This page contains development information for PXP; if you are
looking for the stable distribution, please go here [1].
==============================================================================
Download
==============================================================================
- Current stable release: 1.1.6 [2]
- Current development version: 1.2.0test1 [3]
==============================================================================
Version History
==============================================================================
- 1.2.0test*: New ~minimization option for the [write] and [display] methods
(user wish).
Improvement: better control what is printed as DTD for document#write and
#display
Fix: [Pxp_document.liquefy] terminates now when invoked only on a subtree
of a document
Cleaned up the code a bit so fewer warnings are emitted in the build.
Ported pxp-pp to O'Caml 3.10
- 1.1.96: Works now for O'Caml 3.09, too.
Fix: The "root element check" is disabled in Pxp_dtd. It did not work
together with namespaces.
Pxp_validate: Fix for namespace mode
- 1.1.95: Addition of ulex lexing.
Fix in Pxp_reader.combine.
Revised namespace handling: There are now namespace_scope objects keeping
the scoping structure of the namespaces. The namespace_info stuff has been
removed. The "display" methods can print XML while respecting the scoping
structure.
New exceptions Namespace_not_managed, Namespace_prefix_not_managed,
Namespace_not_in_scope (all replacing Not_found). Methods of
namespace_manager may raise these exceptions.
The event-based representation of XML is now symmetrical to the tree-based
representation, such that it is possible to convert one representation into
the other without loss. The type of events had to be changed to achieve
this effect.
The new module Pxp_event contains functions for the event-based
representation.
Addition of pxp-pp, the PXP preprocessor.
This release requires Ocamlnet 0.98. You should also install ulex. There
are no longer precompiled wlex lexers (use ulex instead).
- 1.1.94.2: Again fixes for the combination of 3.07/wlex
- 1.1.94.1: Fixes for 3.07 concerning the pregenerated wlexers. - New:
Pxp_document.build_node_tree
- 1.1.94: The Pxp_reader module has been completely rewritten. This fixes some
problems with relative URLs. - Pxp_yacc has been split up into four modules:
Pxp_tree_parser contains now the parser API returning object trees,
Pxp_dtd_parser is the parser API returning DTDs, Pxp_ev_parser is the
event-based API, and Pxp_core_parser is the core of the parser. Pxp_yacc is
still available as compatibility API. As part of the module redesign,
Pxp_types includes now parts of its interface from Pxp_core_types_type. I
hope this style of programming is comprehensible. - I think PXP can now
compiled with CVS releases of O'Caml. - It is now possible to turn warnings
into errors. - The event-based parser can now preprocess namespaces.
Furthermore, there are normalization filters.
- 1.1.93: This is a bugfix release. Sometimes files were not closed in
previous versions, but now they are. There were debug statements in the pull
parser code, I have removed them. Finally, some errors in the Makefiles have
been corrected.
- 1.1.92: The whole lexing stuff has been restructured. There is a new tool,
lexpp, that generates the lexers from only five files. Furthermore, much
more 8 bit character sets are now supported as internal encodings. In
previous versions of PXP, the internal representation of the XML trees was
restricted to either UTF-8 or ISO-8859-1. Now, a number of additional
encodings are supported, including the whole ISO-8859 series.
Bugfix: If the processing instruction <?xml...?> occurs in the middle of the
XML document, version 1.1.91 will immediately stop parsing, and ignore the
rest of the file. This is now fixed.
- 1.1.91: The curly braces can now even be used inside attributes, and escape
from normal XML parsing.
There is a new entry point Entry_expr for event-based parsing that expects
either a single element, a single processing instruction, or a single
comment, or whitespace. This allows more fine-grained control of what is
parsed.
There is now a "pull parser". In contrast to the "push parser" introduced in
1.1.90, the calling order of parser and parser user have been inverted, i.e.
the user calls the parser to get ("pull") the next event instead of letting
the parser call back a user function ("push"). An interesting application is
that O'Caml's lazy streams can be used to analyze events. An example can be
found in examles/pullparser.
Pull parsing is not yet well-tested!
- 1.1.90: This version introduces a new event-based interface in Pxp_yacc. For
start tags, end tags, data strings, and several other things that are found
in the XML source so-called events are generated, and a user function is
called for every event. See the directory examples/eventparser for examples.
Another innovation is support for curly braces as escape characters. Inside
elements, the left curly brace escapes from XML parsing and starts a foreign
parser until the matching right curly brace is found:
<element> ... { foreign syntax } ... </element>
The curly braces are borrowed from the XQuery draft standard. They cannot
yet be used inside attribute values. Curly braces are mostly useful in
conjunction with event-based parsing, because it is not yet possible to
include the "value" of the curly brace expression into XML trees.
It is even possible to call the XML parser from the foreign parser as
subparser. However, there not yet enough entry points for the event-based
parser (e.g. you cannot parse just the following processing instruction,
only misc* element misc* or whole documents are possible).
A long-standing bug has been found in the entity layer. When an external
entity A opens an external entity B, and B opens C, relative paths of C have
been interpreted wrong.
--------------------------
[1] see http://www.ocaml-programming.de/packages/documentation/pxp
[2] see http://www.ocaml-programming.de/packages/pxp-1.1.6.tar.gz
[3] see http://www.ocaml-programming.de/packages/pxp-1.2.0test1.tar.gz
