+++ /dev/null
-******************************************************************************
-README - PXP, the XML parser for O'Caml
-******************************************************************************
-
-
-==============================================================================
-Abstract
-==============================================================================
-
-PXP is a validating parser for XML-1.0 which has been written entirely in
-Objective Caml.
-
-PXP is the new name of the parser formerly known as "Markup". PXP means
-"Polymorphic XML parser" and emphasizes its most useful property: that the API
-is polymorphic and can be configured such that different objects are used to
-store different types of elements.
-
-==============================================================================
-Download
-==============================================================================
-
-You can download PXP as gzip'ed tarball [1]. The parser needs the Netstring [2]
-package (0.9.3). Note that PXP requires O'Caml 3.00.
-
-==============================================================================
-User's Manual
-==============================================================================
-
-The manual is included in the distribution both as Postscript document and
-bunch of HTML files. An online version can be found here [3].
-
-==============================================================================
-Author, Credits, Copying
-==============================================================================
-
-PXP has been written by Gerd Stolpmann [4]; it contains contributions by
-Claudio Sacerdoti Coen. You may copy it as you like, you may use it even for
-commercial purposes as long as the license conditions are respected, see the
-file LICENSE coming with the distribution. It allows almost everything.
-
-Thanks also to Alain Frisch and Haruo Hosoya for discussions and bug reports.
-
-==============================================================================
-Description
-==============================================================================
-
-PXP is a validating XML parser for O'Caml [5]. It strictly complies to the
-XML-1.0 [6] standard.
-
-The parser is simple to call, usually only one statement (function call) is
-sufficient to parse an XML document and to represent it as object tree.
-
-Once the document is parsed, it can be accessed using a class interface. The
-interface allows arbitrary access including transformations. One of the
-features of the document representation is its polymorphic nature; it is simple
-to add custom methods to the document classes. Furthermore, the parser can be
-configured such that different XML elements are represented by objects created
-from different classes. This is a very powerful feature, because it simplifies
-the structure of programs processing XML documents.
-
-Note that the class interface does not comply to the DOM standard. It was not a
-development goal to realize a standard API (industrial developers can this much
-better than I); however, the API is powerful enough to be considered as
-equivalent with DOM. More important, the interface is compatible with the XML
-information model required by many XML-related standards.
-
-------------------------------------------------------------------------------
-Detailed feature list
-------------------------------------------------------------------------------
-
-- The XML instance is validated against the DTD; any violation of a validation
- constraint leads to the rejection of the instance. The validator has been
- carefully implemented, and conforms strictly to the standard. If needed, it
- is also possible to run the parser in a well-formedness mode.
-
-- If possible, the validator applies a deterministic finite automaton to
- validate the content models. This ensures that validation can always be
- performed in linear time. However, in the case that the content models are
- not deterministic, the parser uses a backtracking algorithm which can be
- much slower. - It is also possible to reject non-deterministic content
- models.
-
-- In particular, the validator also checks the complicated rules whether
- parentheses are properly nested with respect to entities, and whether the
- standalone declaration is satisfied. On demand, it is checked whether the
- IDREF attributes only refer to existing nodes.
-
-- Entity references are automatically resolved while the XML text is being
- scanned. It is not possible to recognize in the object tree where a
- referenced entity begins or ends; the object tree only represents the
- logical structure.
-
-- External entities are loaded using a configurable resolver infrastructure.
- It is possible to connect the parser with an arbitrary XML source.
-
-- The parser can read XML text encoded in a variety of character sets.
- Independent of this, it is possible to choose the encoding of the internal
- representation of the tree nodes; the parser automatically converts the
- input text to this encoding. Currently, the parser supports UTF-8 and
- ISO-8859-1 as internal encodings.
-
-- The interface of the parser has been designed such that it is best
- integrated into the language O'Caml. The first goal was simplicity of usage
- which is achieved by many convenience methods and functions, and by allowing
- the user to select which parts of the XML text are actually represented in
- the tree. For example, it is possible to store processing instructions as
- tree nodes, but the parser can also be configured such that these
- instructions are put into hashtables. The information model is compatible
- with the requirements of XML-related standards such as XPath.
-
-- In particular, the node tree can optionally contain or leave out processing
- instructions and comments. It is also possible to generate a "super root"
- object which is the parent of the root element. The attributes of elements
- are normally not stored as nodes, but it is possible to get them wrapped
- into nodes.
-
-- There is also an interface for DTDs; you can parse and access sequences of
- declarations. The declarations are fully represented as recursive O'Caml
- values.
-
-------------------------------------------------------------------------------
-Code examples
-------------------------------------------------------------------------------
-
-This distribution contains several examples:
-
-- validate: simply parses a document and prints all error messages
-
-- readme: Defines a DTD for simple "README"-like documents, and offers
- conversion to HTML and text files [7].
-
-- xmlforms: This is already a sophisticated application that uses XML as style
- sheet language and data storage format. It shows how a Tk user interface can
- be configured by an XML style, and how data records can be stored using XML.
-
-------------------------------------------------------------------------------
-Restrictions and missing features
-------------------------------------------------------------------------------
-
-The following restrictions apply that are not violations of the standard:
-
-- The attributes "xml:space", and "xml:lang" are not supported specially. (The
- application can do this.)
-
-- The built-in support for SYSTEM and PUBLIC identifiers is limited to local
- file access. There is no support for catalogs. The parser offers a hook to
- add missing features.
-
-- It is currently not possible to check for interoperatibility with SGML.
-
-The following features are also missing:
-
-- There is no special support for namespaces. (Perhaps in the next release?)
-
-- There is no support for XPATH or XSLT.
-
-However, I hope that these features will be implemented soon, either by myself
-or by contributors (who are invited to do so).
-
-------------------------------------------------------------------------------
-Recent Changes
-------------------------------------------------------------------------------
-
-- Changed in 1.0:
- Support for document order.
-
-- Changed in 0.99.8:
- Several fixes of bugs reported by Haruo Hosoya and Alain Frisch.
- The class type "node" has been extended: you can go directly to the next and
- previous nodes in the list; you can refer to nodes by position.
- There are now some iterators for nodes: find, find_all, find_element,
- find_all_elements, map_tree, iter_tree.
- Experimental support for viewing attributes as nodes; I hope that helps
- Alain writing his XPath evaluator.
- The user's manual has been revised and is almost up to date.
-
-- Changed in 0.99.7:
- There are now additional node types T_super_root, T_pinstr and T_comment,
- and the parser is able to create the corresponding nodes.
- The functions for character set conversion have been moved to the Netstring
- package; they are not specific for XML.
-
-- Changed in 0.99.6:
- Implemented a check on deterministic content models. Added an alternate
- validator basing on a DFA. - This means that now all mandatory features for
- an XML-1.0 parser are implemented! The parser is now substantially complete.
-
-- Changed in 0.99.5:
- The handling of ID and IDREF attributes has changed. The index of nodes
- containing an ID attribute is now separated from the document. Optionally
- the parser now checks whether the IDREF attributes refer to existing
- elements.
- The element nodes can optionally store the location in the source XML code.
- The method 'write' writes the XML tree in every supported encoding.
- (Successor of 'write_compact_as_latin1'.)
- Several smaller changes and fixes.
-
-- Changed in 0.99.4:
- The module Pxp_reader has been modernized. The resolver classes are simpler
- to use. There is now support for URLs.
- The interface of Pxp_yacc has been improved: The type 'source' is now
- simpler. The type 'domspec' has gone; the new 'spec' is opaque and performs
- better. There are some new parsing modes.
- Many smaller changes.
-
-- Changed in 0.99.3:
- The markup_* modules have been renamed to pxp_*. There is a new
- compatibility API that tries to be compatible with markup-0.2.10.
- The type "encoding" is now a polymorphic variant.
-
-- Changed in 0.99.2:
- Added checks for the constraints about the standalone declaration.
- Added regression tests about attribute normalization, attribute checks,
- standalone checks.
- Fixed some minor errors of the attribute normalization function.
- The bytecode/native archives are now separated in a general part, in a
- ISO-8859-1-relevant part, and a UTF-8-relevant part. The parser can again be
- compiled with ocamlopt.
-
-- Changed in 0.99.1:
- In general, this release is an early pre-release of the next stable version
- 1.00. I do not recommend to use it for serious work; it is still very
- experimental!
- The core of the parser has been rewritten using a self-written parser
- generator.
- The lexer has been restructured, and can now handle UTF-8 encoded files.
- Numerous other changes.
-
-
---------------------------
-
-[1] see http://www.ocaml-programming.de/packages/pxp-1.0.tar.gz
-
-[2] see http://www.ocaml-programming.de/packages/documentation/netstring
-
-[3] see http://www.ocaml-programming.de/packages/documentation/pxp/manual
-
-[4] see mailto:gerd@gerd-stolpmann.de
-
-[5] see http://caml.inria.fr/
-
-[6] see http://www.w3.org/TR/1998/REC-xml-19980210.html
-
-[7] This particular document is an example of this DTD!
-
-
-
projects / helm.git / blobdiff