Introduction
 ------------
 
 XSLTools is a collection of modules and packages facilitating the development
 of applications based on XML, XSL stylesheets and transformations, notably Web
 applications involving complicated Web forms potentially consisting of
 editable hierarchical structures and potentially involving "live" or "in-page"
 dynamic updates to portions of those Web forms.
 
 Quick Start
 -----------
 
 Try running the demo:
 
 python tools/demo.py
 
 An introductory guide to creating applications can be found in the docs
 directory - see docs/index.html for the start page.
 
 Contact, Copyright and Licence Information
 ------------------------------------------
 
 The current Web page for XSLTools at the time of release is:
 
 http://www.boddie.org.uk/python/XSLTools.html
 
 Copyright and licence information can be found in the docs directory - see
 docs/COPYING.txt, docs/lgpl-3.0.txt, docs/gpl-3.0.txt,
 docs/LICENCE-Sarissa-lgpl.txt and docs/LICENCE-Sarissa-gpl.txt for more
 information.
 
 Additional Software
 -------------------
 
 The XSLTools examples make use of sarissa.js from the Sarissa distribution,
 release 0.9.8.1. Copies of this file are found in the Resources/scripts
 directory within each example's package.
 
 Dependencies
 ------------
 
 XSLTools has the following basic dependencies:
 
 Packages                    Release Information
 --------                    -------------------
 
 libxml2dom                  0.4.3
 libxml2 and libxslt         Some combinations may not be reliable!
                             Tested with libxml2 2.6.17 and libxslt 1.1.12
                             Tested with libxml2 2.6.27 and libxslt 1.1.20
                             libxslt 1.1.17 should be avoided
 
 The example Web applications require WebStack (release 1.3 or later).
 The example PyQt applications have been tested with PyQt 3.15.
 
 New in XSLTools 0.6 (Changes since XSLTools 0.5)
 ------------------------------------------------
 
   * Added modular request handling methods to XSLFormsResource, altering some
     of the examples to demonstrate the usage and overriding of these methods
     in preference to overriding respond_to_form.
   * Added methods to the Form class to support modular request handling.
   * Added information about XSLT extension function usage to the advanced
     template design document, linking to the housekeeping annotations section
     of the template attribute reference guide.
 
 New in XSLTools 0.5 (Changes since XSLTools 0.4.6)
 --------------------------------------------------
 
   * Renamed template:id to template:section in order to get around problems
     and potential future problems with browsers (such as Konqueror 3.5.6)
     which get confused loading documents with multiple id attributes, even if
     only one is unprefixed. WARNING! This change is not backwards compatible.
   * Added Ubuntu Feisty (7.04) package support.
   * Tidied the documentation HTML.
 
 New in XSLTools 0.4.6 (Changes since XSLTools 0.4.5)
 ----------------------------------------------------
 
   * Improved the Login module, enabling the VerySimpleWithLogin example for
     various frameworks.
   * Relicensed under the LGPL version 3 or later.
   * Upgraded to Sarissa 0.9.7.8 (compatible with LGPL/GPL version 3), removing
     a test around DOMParser so that Konqueror 3.4.0 is still supported.
 
 New in XSLTools 0.4.5 (Changes since XSLTools 0.4.4)
 ----------------------------------------------------
 
   * Fixed the result of transformations in XSLOutput: proper document nodes
     are now produced.
   * Added an XSLForms.Resources.Login module which provides resources to
     support login screens and redirects.
   * Fixed newlines in the attributes created from fields in XSLForms: CR
     characters are no longer included since this caused the doubling up of
     newlines in Firefox.
 
 New in XSLTools 0.4.4 (Changes since XSLTools 0.4.3)
 ----------------------------------------------------
 
   * Fixed translation selection for the template:i18n annotation attribute,
     not just for the template:i18n extension function - more apologies for
     resulting output changes!
   * Improved the template fixing stylesheet and added some documentation for
     the script and the related expr-prefix attribute.
   * Introduced WebStack 1.2.2 EncodingSelector and encoding changes.
   * Added docstring and return value for the write_month_to_document function
     in XSLTools.XMLCalendar.
 
 New in XSLTools 0.4.3 (Changes since XSLTools 0.4.2)
 ----------------------------------------------------
 
   * Fixed translation selection when an unsupported locale is specified,
     choosing the first locale as the default (rather than exposing the values
     themselves as translations). Note that this is an unfortunate and subtle
     change which may affect application output - apologies are hereby offered!
 
 New in XSLTools 0.4.2 (Changes since XSLTools 0.4.1)
 ----------------------------------------------------
 
   * Added a content type check in the XSLFormsResource class, permitting
     non-form-based resources to access the raw request data, rather than have
     the data processed unsuccessfully and consequently discarded.
   * Added a script and a function to fix template namespaces after editing in
     a careless editor.
   * Changed libxml2mod and libxsltmod import details to try libxmlmods -
     suggested by Lucian Wischik for libxml2dom.
 
 New in XSLTools 0.4.1 (Changes since XSLTools 0.4)
 --------------------------------------------------
 
   * Made translations specified using the template:i18n annotation take
     priority over template:value annotations.
   * Added expression-based template:i18n annotations, and provided fallback
     output for such translations based on the value of the evaluated
     expression.
 
 New in XSLTools 0.4 (Changes since XSLTools 0.3.1)
 --------------------------------------------------
 
   * Changed the preparation of templates to produce rule-based output
     stylesheets, thus permitting recursive templates. This requires an extra
     expr-prefix annotation to be used in certain kinds of templates.
   * Added a recursive template example application.
   * Changed fragment production to use original template documents instead of
     output stylesheets.
   * Changed the in_page_resources attribute to provide the output identifier,
     thus changing the prepare_fragment method in Web resources so that only
     the fragment identifier needs to be supplied.
   * Added the XSLForms.Resources.WebResources.prepare_resources method for the
     preparation of initialiser and output stylesheets before an application is
     run.
   * Changed selectors to not automatically create elements in the form data
     document unless requested to do so. Introduced a Form.get_selector
     method in XSLForms.Fields.
   * Permitted the creation of hierarchies of elements in
     XSLForms.Utils.add_elements.
   * Introduced dynamic parameter evaluation for multiple-choice fields in
     order to support sources of multiple-choice values which reside in the
     form data document itself.
   * Added the FixNamespace.xsl stylesheet to correct documents saved by HTML
     editors which strip namespace prefixes.
   * Fixed filesystem encoding issues in the Candidate example; fixed language
     preference access in the Configurator and VerySimple examples.
   * Changed the BaseHTTPRequestHandler version of the Candidate example to
     store data in a subdirectory of the current working directory, thus
     allowing the demonstration application to work after package installation.
 
 New in XSLTools 0.3.1 (Changes since XSLTools 0.3)
 --------------------------------------------------
 
   * Fixed copyright and licensing information.
 
 New in XSLTools 0.3 (Changes since XSLTools 0.2)
 ------------------------------------------------
 
   * Introduced copying of multiple-choice value element contents so that
     option element labels can differ from the underlying values.
   * Added internationalisation support, providing the template:i18n annotation
     and the template:i18n extension function.
   * Updated the documentation to cover the above new features.
   * Fixed non-GET/POST request method handling in WebResources.
   * Added the xslform_preparemacro.py script.
   * Added an experimental template:range extension function.
 
 New in XSLTools 0.2 (Changes since XSLTools 0.1)
 ------------------------------------------------
 
   * Made a new XSLTools package and moved XSLOutput into it.
   * Improved serialisation of transformation results so that output options
     are observed (in some cases, at least).
   * Fixed stylesheet and reference document paths so that libxslt should not
     now become confused by ambiguous relative paths.
   * Added expression parameters to XSLOutput.Processor so that in-document
     data can be used to, for example, initialise multiple-choice field values.
   * Added input/initialiser support so that input documents can be tidied or
     initialised using information from the template.
   * Added template:init for use with template:element in XSLForms to control
     element initialisation where necessary.
   * Added special high-level "macro" attributes (eg. template:attribute-field)
     which should make templates easier to write and maintain.
   * Added template:if to XSLForms, providing conditional output of annotated
     elements.
   * Added set_document to XSLForms.Fields.Form.
   * Added prepare_parameters to the XSLFormsResource class in the
     XSLForms.Resources.WebResources module.
   * Added element-path, url-encode and choice XSLForms extension functions.
   * Improved Unicode support in the XSLForms extension functions.
   * Changed in-page requests to contain proper POST data.
   * Fixed checkbox and radiobutton value detection in XSLForms.js.
   * Updated the code to work with WebStack 1.0 changes and adopted the
     new-style WebStack demonstration mechanism.
   * Added XMLCalendar and XMLTable (to the XSLTools package).
   * Added a dictionary (or word lookup) example application.
   * Added a job candidate profile (or CV editor) example application.
   * Added a template attribute reference and an XSLFormsResource guide to the
     documentation.
   * Added Debian package support (specifically Ubuntu package support).
   * Added missing COPYING.txt file.
   * Renamed the scripts to avoid naming issues in system-wide installations.
   * Added a PyQt example based on the system configurator example, with the
     form prepared in Qt Designer. This example runs in PyQt and in a Web
     environment without any changes to the application code. In-page updates
     are currently not implemented in the Web version, however.
 
 Notes on In-Page Update Functionality
 -------------------------------------
 
 Special note #1: Konqueror seems in certain cases to remember replaced form
 content (when replaceChild is used to replace regions of the page which
 include form elements). This causes the browser to believe that more form
 fields exist on the page than actually do so, and subsequent form submissions
 thus include the values of such removed fields. A special hack is in place to
 disable form fields by changing their names, thus causing Konqueror to not
 associate such fields with the real, active fields; this hack does not seem to
 cause problems for Mozilla. This needs some investigation to determine in
 exactly which circumstances the problem arises.
 
 Special note #2: Konqueror also seems to crash if asked to find elements using
 an empty 'id' attribute string. This needs some investigation to see if it
 really is the getElementById call that causes the crash.
 
 Special note #3: Konqueror's XMLHttpRequest seems to append null characters to
 the end of field values. Attempting to prune them before the request is sent
 fails with a function like the following:
 
 function fixValue(fieldValue) {
     if (fieldValue.length == 0) {
         return fieldValue;
     } else if (fieldValue[fieldValue.length - 1] == '\0') {
         return fieldValue.substr(0, fieldValue.length - 1);
     } else {
         return fieldValue;
     }
 }
 
 This may be because it is the entire message that is terminated with the null
 character, and that this happens only upon sending the message. Consequently,
 some frameworks (notably mod_python) do not support in-page functionality when
 used from Konqueror.
 
 Various browsers (eg. Mozilla/Firefox, Konqueror) will not allow the
 XMLHttpRequest in-page updates to function unless the URL used in the
 requestUpdate JavaScript function is compatible with the URL at which the
 browser finds the application. Currently, relative URLs are in use to avoid
 this issue of compatibility, but should an absolute URL be deduced using the
 WebStack API and then used, it may be possible that the values returned by
 that API do not match the actual addresses entered into the address bar of the
 browser.
 
 To check the behaviour of the applications, it is possible to view the
 document source of the pages served by applications and to verify that the
 URLs mentioned in the JavaScript function calls (to 'requestUpdate') either be
 a relative link or involve a URL similar to that which appears in the
 browser's address bar. In some environments, the use of 'localhost' addresses
 often confuses the browser and server; one workaround is to use real host
 names or addresses instead of 'localhost'.
 
 Choosing an element-path:
 
 When specifying the "context" of the in-page update, one must imagine which
 element the template fragment should operate within. If the template:id
 attribute marks a particular section, then the element-path should be a path
 to the applicable context element for that section in the complete template
 document. Note that if a template:element attribute appears on the same
 element as the template:id attribute then the element-path should refer to the
 element specified in the template:element attribute.
 
 Choosing where to put template:attribute, template:id and id:
 
 When specifying the extent of a template fragment, one must be sure not to put
 the template:id attribute on the same element as a template:attribute
 annotation; otherwise, the generated code will be improperly extracted as a
 fragment producing two versions of the element - one for when the specified
 attribute is present, and one for when it is not present. Generally,
 template:id and id can be placed on the same node, however.
 
 Stable element ordering and element-path:
 
 Within the element-path, the numbering of the elements will start at 1.
 Therefore it is vital to choose a region of the form data structure with the
 element-path which is isolated from surrounding elements whose positions would
 otherwise be dependent on a stable ordering of elements, and whose processing
 would be disrupted if some new elements suddenly appeared claiming the same
 positions in the document. For example:
 
   <item value="">         .../item$1/value
     <type value=""/>      .../item$1/type$1/value
     <comment value=""/>   .../item$1/comment$2/value
   </item>
 
   In-page update...
 
   <comment value=""/>     .../item$1/comment$1/value
 
 Notes on XSL
 ------------
 
 libxslt seems to be quite liberal on the definition of runtime parameters, in
 that there is no apparent need to explicitly declare the corresponding global
 variables in stylesheets. Whilst this is nice, we may eventually need to
 detect such variables and add them in the preparation process.
 
 Release Procedures
 ------------------
 
 Update the XSLTools/__init__.py and XSLForms/__init__.py __version__
 attributes.
 Change the version number and package filename/directory in the documentation.
 Change code examples in the documentation if appropriate.
 Update the release notes (see above).
 Check the setup.py file and ensure that all package directories are mentioned.
 Check the release information in the PKG-INFO file and in the package
 changelog (and other files).
 Tag, export.
 Generate the example resources.
 Generate the API documentation.
 Remove generated .pyc files: find . -name "*.pyc" | xargs rm
 Archive, upload.
 Upload the introductory documentation.
 Update PyPI, PythonInfo Wiki, Vaults of Parnassus entries.
 
 Generating the Example Resources
 --------------------------------
 
 In order to prepare the example resources, the prepare_demo.py script must be
 run as follows:
 
 python tools/prepare_demo.py
 
 This will ensure that all initialiser and output stylesheets are created and
 are thus installed by packages.
 
 Generating the API Documentation
 --------------------------------
 
 In order to prepare the API documentation, it is necessary to generate some
 Web pages from the Python source code. For this, the epydoc application must
 be available on your system. Then, inside the distribution directory, run the
 apidocs.sh tool script as follows:
 
 ./tools/apidocs.sh
 
 Some warnings may be generated by the script, but the result should be a new
 apidocs directory within the distribution directory.
 
 Making Packages
 ---------------
 
 To make Debian-based packages:
 
   1. Create new package directories under packages if necessary.
   2. Make a symbolic link in the distribution's root directory to keep the
      Debian tools happy. Try one of the following:
 
      ln -s packages/ubuntu-hoary/python2.4-xsltools/debian/
      ln -s packages/ubuntu-feisty/python-xsltools/debian/
 
   3. Run the package builder:
 
      dpkg-buildpackage -rfakeroot
 
   4. Locate and tidy up the packages in the parent directory of the
      distribution's root directory.