-
-PROPOSAL
-
-Updated 5 September 2002.
-
-This is a proposed roadmap for the further development of Expat. The
-primary purpose for making this proposal is to determine whether our
-ideas for continued development are aligned with the needs of the
-community. We welcome comment both from Expat users, would-be users,
-and members of the XML community who have decided against using Expat
-for technical reasons directly related to Expat.
-
-Discussion of this document should be directed to the expat-discuss
-mailing list.
-
-
-Goals
-
-We do not plan to alter the goals of the Expat
-project. We intend to continue to develop Expat to have the following
-qualities:
-
-
-- Fast
-
-- Conformant to XML 1.0 and Namespaces
-
-- Easy to use from C
-
-- Easy to wrap / bind for non-C languages
-
-- Sufficient to build DOM and SAX on top of
- (any final specification for XML)
-
-- Modest memory footprint
-
-- Portable
-
-
-
-Non-Goals
-
-
-- Parsing anything that isn't XML
-
-- DOM (any level)
-
-- SAX (any version)
-
-- Data bindings
-
-- Watching the kids
-
-
-
-Historical Background
-
-James Clark initially developed Expat, releasing three stable
-versions, identified as versions 1.0, 1.1, and 1.2. Clark Cooper
-created a forked version of Expat based on Expat 1.1, for use in the
-XML::Parser extension module for Perl.
-
-As James Clark's interests shifted, and his development moved to
-the Java environment, the authors of 3rd party language bindings found
-it increasingly difficult to integrate Expat with their languages, and
-other developers found it difficult to get fixes accepted into Expat
-and released. A small group of extension authors were gathered by
-Paul Prescod in the hope that Expat could be formed into a more
-readily usable library for both direct use in C-language applications
-and indirect use from other languages. This group was led by Clark
-Cooper and Fred Drake, and received sanction to take over maintenance
-of Expat from James Clark. The project is hosted on SourceForge.
-This group made their first release as Expat 1.95.0 in September
-2000.
-
-Since that time, incremental releases of Expat have been made on a
-sporadic schedule, improving functionality and portability with each
-release.
-
-
-Expat Development Roadmap
-
-Now that our goals and non-goals have been spelled out, let's take
-a look at how we should get there from where we are now. This will be
-broken down into two stages: near future activities and far future
-activities. In spite of the somewhat temporal labeling of these
-categories, please realize that no actual scheduling has been done,
-nor is that considered relevant at this time. Actual time to meet
-these goals is dependent on the availability of resources to work on
-Expat. Parallel development may also happen, depending on the
-specific interests of contributers.
-
-Near Future Activity
-
-The target of the current line of development will be to release Expat
-2.0. The intent is that once Expat 2.0 is released, most of the
-development activity for this line will be maintenance, and will be
-driven by user-provided problem reports. These are the goals for
-goals we have specific to the release of Expat 2.0:
-
-
-- Stabilize the current API with some minor revisions to make error
- reporting more explicit to allow better reporting and diagnosis.
-
-- Introduce a new feature-test macro, XML_MINIMAL, parallel to
- XML_DTD, XML_UNICODE, and XML_UNICODE_WCHAR_T. Defining the new
- feature when compiling Expat will cause functions that are not
- relevant to the rest of the feature macros. (For example, if
- XML_DTD is not set but XML_MINIMAL is, the functions that set
- handlers for DTD-related events won't be included at all.) This
- is intended to make it easier to use Expat in small-memory
- devices.
-
-- API revisions will be made to improve the runtime discoverability of
- Expat capabilities.
-
-- Improve portability and performance.
-
-- Substantially improve regression tests.
-
-- Improve documentation.
-
-- Full support for 64-bit platforms. (There are some known decoding
- problems currently.)
-
-
-When we're confident that the minor API changes are "right", we'll
-finallize the API and release Expat 2.0. Should additional functions
-be required as evolutionary improvements, the minor version number
-will be incremented, but all existing functions will be maintained for
-backward compatibility. Releases that are strictly bug fixes will
-have the same minor version number and will gain a "micro" version
-number (sometimes called a "patch level").
-
-
-Far Future Activity
-
-Once Expat 2.0 has been released, it will be maintained on a CVS
-branch. The head of CVS will be used to develop Expat 3.0. The
-changes in Expat 3.0 will be more substantial and will include
-important API changes. At this time, we're looking at the following
-changes:
-
-
-- More powerful event API
--
-
The new API will be sufficiently detailed that a complete and
- detailed DOM structure can be built, including both internal and
- external entity boundaries in parsed character data content,
- attribute value content, and entity values (such as found in
- internal entity declarations).
-
- This API will of necessity be somewhat more complex than the
- current API, but we expect the current API can be implemented on top
- of the new API. For users for whom the Expat 2.0 API is
- sufficiently powerful, this API will remain available.
-
-
-- Support for either pull or suspendable parsing
--
-
The new API will need to support some way to interrupt processing
- without having to parse all XML text passed to the parser so far.
- This can be done by either using a pull-based model or a push-based
- model (similar to the current API) with the added ability to suspend
- parsing on request.
-
- The specific API will depend on the model selected; either a
- pull-based model or an suspension model can support each other with
- little additional work, and the current push model can be built on
- top of either.
-
- The specific model and API will be discussed on the expat-discuss
- mailing list.
-
-
- - New encoding support
--
-
A new library may be added to the Expat package that provides a
- flexible architecture for defining new encodings, and provides a
- large range of common encodings. (It should be possible to develop
- this so that it supports both Expat 2.0 and Expat 3.0.)
-
- Another approach which will be considered will be to support
- Expat's requirements for decoders using one of the existing open
- source encoding support libraries that meets Expat's requirements
- for portability. Possible technical approaches would include
- implementing an adapter, and developing such an external library to
- include direct support for the kind of interface support Expat
- needs.
-
-
-- XML 1.1 (including Namespaces in XML
- 1.1), if it ever happens
--
-
Well, we're hoping, but it's not time to code for this yet.
-
-
-
-Additional goals may be added during the development of Expat 3.0;
-it's just too early to tell.
-
-
- |
- 
- 