BitWorking

Mission

The main objective of the Efficient XML Interchange (EXI) Working Group is to develop a format that allows efficient interchange of the XML Information Set, based on the conclusions of the XML Binary Characterization Working Group.

Scope and Goals

XML has been enormously successful as a markup language for documents and data, { So let's start screwing with it! } but is not an optimal format for all purposes. { Really? You mean it's not a floor wax and dessert topping? Let's be clear, XML isn't for all applications. If it doesn't fit your needs don't use it! } The XML Binary Characterization Working Group established a set of use cases for which XML employment may be problematic. The Efficient XML Interchange Working Group is chartered to define an alternative encoding of the XML Information Set that addresses at least the minimum requirements identified by the XML Binary Characterization Working Group. The Working Group shall also consider properties that shouldn't be prevented, as listed in the second list of the decision tree. Such support will be considered as extensions to the XML Information Set or extensions introduced in the XML Schema 1.0 Post–Schema–Validation Infoset and in the XQuery 1.0 and XPath 2.0 data model.

The goals of this Working Group are:

1. Fulfill the design goals of XML with the following exceptions: { Yeah, those goals were too lofty and promoted too much interop. What's the new motto at the W3C? "Aim low?" }
   1. The interchange format must be compatible with the XML Information Set instead of being “compatible with SGML” (XML goal 3); { Interop? We don't need no steeenking interop... }
   2. For performance reasons, the format is not required to be “human–legible and reasonably clear” (XML goal 6); { Because no one ever needs to debug services. We'll all have perfect libraries for that. The tools will save us! The tools will save us! }
   3. Terseness in efficient interchange is important (XML Goal 10). { Hijacking popular specifications is easier than coming up with something new on our own. }
2. Address all requirements and use cases from the XML Binary Characterization Working Group;
3. Maintaining the existing interoperability between XML applications, as well as XML specifications; { Because interop between specs is important. Interop betweeen applications? That's for pansies. }
4. Establish sufficient confidence in the proposed format, in particular establishing confidence that the performance gains are significant, and the potential for disruption to existing processors is small; { Yeah, small disruption for the processors, unless those processors happen to be human. }

There are several approaches to achieve the integration with XML. The Working Group will provide at least one way for the new format to be both recognized as XML by existing parsers { Because we realize that our only chance at being adopted is to co-opt the name XML. I mean really, we can count on one hand the number of people on the planet that know ASN.1. } and also rejected in a meaningful way, such as by defining a new value for the pseudo–attribute encoding. { I'll give you rejected in a meaningful way. }

The Working Group will start by considering existing solutions and will evaluate each in terms of implementability and performance against the requirements and use cases documents produced by the XML Binary Characterization Working Group. { We will carefully go through the motions of pretending to care. }

Out of scope

This Working Group is not chartered to:

1. Introduce a new data model for XML; { That was actually considered!?! You mean this could have been even worse?!? }
2. Develop an application specific format. Like XML itself, the new format must support a wide variety of applications. { But don't worry about interoperating with any applications currently running on the planet. }

Success criteria

Two of the entrance criteria used for the Last Call phase will be:

1. the Working Group Note on the impact of the new format on existing XML technologies; { Memo to self: Write memo to self acknowledging the irreparable harm we've done to XML and the internet. }
2. the Working Group Note analyzing the performance gains of the new format, based on the criteria included in the measurement methodologies document. For example, in the case of compactness, the information compression is expected to be at most 20% larger than its equivalent ASN.1 PER, when a schema optimization is in use. Some of the analysis require to have an implementation and will be done during the Candidate Recommendation phase, such as processing efficiency.

Careful review will be given to the feedback from other Groups, within and outside the XML Activity. { I doubt it. } Findings that suggest that the proposed format has a significant impact and disruption of existing XML technologies and processors might dissuade W3C from advancing the format to W3C Candidate Recommendation, or might persuade W3C to do so but without referring to the format as a flavor of XML. { It hasn't stopped you so far, why start now? }

Two of the entrance criteria used for the Proposed Recommendation phase will be:

1. demonstrate the performance gains of the new format, based on the prior analysis done as an entrance criteria of the Last Call phase. In addition, an analysis regarding the properties that need an implementation to be evaluated, such as processing efficiency, will be conducted.
2. demonstrate at least two interoperable implementations supporting all the features provided in the specification. One of the implementations must be available for public use.

The Working Group may at any stage recommend the use of an already published format, provided that it satisfies the above criteria, instead of providing a W3C Recommendation. { We reserve the right to sell out. }