Edit comment LC-2168 for Efficient Extensible Interchange Working Group

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Comment LC-2168

Comment Shortname:

Commenter: UCHIDA Hitoshi <uchida.hitoshi@canon.co.jp>

Message-id:

Section of the document concerned:

[Free text description]Document as a wholeEfficient XML Interchange (EXI) Format 1.0 /**/ code... Efficient XML Interchange (EXI) Format 1.0 W3C Working Draft 28 July 2008 Abstract Status of this Document Table of Contents Appendices 1. Introduction [Definition:]   [Definition:]   [Definition:]   1.1 History and Design 1.2 Notational Conventions and Terminology [Definition:]   2. Design Principles 3. Basic Concepts 4. EXI Streams [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   4. EXI Streams [Definition:]  An EXI stream is an EXI heade... 4. EXI Streams [Definition:]  An EXI stream is an EXI heade... name prefix local-element-ns public qname system text uri value 5. EXI Header [Definition:]   5.1 EXI Cookie [Definition:]   5.2 Distinguishing Bits [Definition:]   5.3 EXI Format Version [Definition:]   Example 5-1. EXI Format Version Examples 5.4 EXI Options [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   6. Encoding EXI Streams [Definition:]   6.1 Determining Event Codes Example 6-1. Example productions with event codes 6.2 Representing Event Codes Example 6-2. Example event code encoding 6.3 Fidelity Options Preserve.prefixes Preserve.lexicalValues 7. Representing Event Content [Definition:]   7. Representing Event Content The content of each event in... 7. Representing Event Content The content of each event in... 7.1 Built-in EXI Datatype Representations 7.1.1 Binary 7.1.2 Boolean 7.1.3 Decimal 7.1.4 Float 7.1.5 Integer 7.1.6 Unsigned Integer Example 7-1. Example algorithm for decoding an Unsigned Inte... 7.1.7 QName 7.1.8 Date-Time 7.1.9 n-bit Unsigned Integer 7.1.10 String 7.1.10.1 Restricted Character Sets 7.1.11 List 7.2 Enumerations 7.3 String Table 7.3.1 String Table Partitions [Definition:]   7.3.2 Partitions Optimized for Frequent use of Compact Identifiers 7.3.3 Partitions Optimized for Frequent use of String Literals 7.4 Datatype Representation Map [Definition:]   Example 7-2. datatypeRepresentationMap indicating all Decima... Example 7-3. datatypeRepresentationMap illustrating a user-d... 8. EXI Grammars 8.1 Grammar Notation 8.1.1 Fixed Event Codes Example 8-1. Example productions with fixed event codes 8.1.2 Variable Event Codes Example 8-2. Example productions that use macro non-terminal... Example 8-3. Example non-terminal macros and its productions... Example 8-4. Expanded productions equivalent to the producti... 8.2 Grammar Event Codes Example 8-5. Example productions with event codes 8.3 Pruning Unneeded Productions Example 8-6. Example productions with full fidelity Example 8-7. Example productions after pruning 8.4 Built-in XML Grammars 8.4.1 Built-in Document Grammar 8.4.2 Built-in Fragment Grammar 8.4.3 Built-in Element Grammar [Definition:]   8.5 Schema-informed Grammars 8.5.1 Schema-informed Document Grammar 8.5.2 Schema-informed Fragment Grammar 8.5.3 Schema-informed Element Fragment Grammar 8.5.4 Schema-informed Element and Type Grammars [Definition:]   [Definition:]   8.5.4.1 EXI Proto-Grammars 8.5.4.1.1 Grammar Concatenation Operator 8.5.4.1.2 Element Grammars 8.5.4.1.3 Type Grammars 8.5.4.1.3.1 SimpleType Grammars 8.5.4.1.3.2 Complex Type Grammars 8.5.4.1.3.3 Complex Ur-Type Grammar 8.5.4.1.4 Attribute Uses 8.5.4.1.5 Particles 8.5.4.1.6 Element Terms 8.5.4.1.7 Wildcard Terms 8.5.4.1.8 Model Group Terms 8.5.4.1.8.1 Sequence Model Groups 8.5.4.1.8.2 Choice Model Groups 8.5.4.1.8.3 All Model Groups 8.5.4.2 EXI Normalized Grammars 8.5.4.2.1 Eliminating Productions with no Terminal Symbol 8.5.4.2.2 Eliminating Duplicate Terminal Symbols 8.5.4.3 Event Code Assignment 8.5.4.4 Undeclared Productions 8.5.4.4.1 Adding Productions when Strict is False Like an element, an attribute may occur in a schema-invalid... 8.5.4.4.2 Adding Productions when Strict is True 9. EXI Compression 9.1 Blocks 9.2 Channels 9.2.1 Structure Channel 9.2.2 Value Channels 9.3 Compressed Streams 10. Conformance 10.1 EXI Stream Conformance [Definition:]   [Definition:]   [Definition:]   10.2 EXI Processor Conformance A References A.1 Normative References IETF RFC 1951 IETF RFC 2119 ISO/IEC 10646 Unicode Database XML 1.0 XML Information Set XML Schema Structures XML Schema Datatypes A.2 Other References Efficient XML EXI Measurements Note EXI Primer EXI Evaluation Greibach Normal Form Huffman Coding ISO/IEC 19757-2:2003 SOAP 1.2 XBC Measurement Methodologies XBC Use Cases XBC Properties B Infoset Mapping B.1 Document Information Item B.2 Element Information Items B.3 Attribute Information Item B.4 Processing Instruction Information Item B.5 Unexpanded Entity Reference Information item B.6 Character Information item B.7 Comment Information item B.8 Document Type Declaration Information item B.9 Unparsed Entity Information Item B.10 Notation Information Item B.11 Namespace Information Item C XML Schema for EXI Options Header D Initial Entries in String Table Partitions D.1 Initial Entries in Uri Partition D.2 Initial Entries in Prefix Partitions D.3 Initial Entries in Local-Name Partitions E Deriving Character Sets from XML Schema Regular Expressions E Deriving Character Sets from XML Schema Regular Expressio... F Example Encoding (Non-Normative) G Schema-informed Grammar Examples (Non-Normative) Example G-1. Example XML Schema fragment G.1 Proto-Grammar Examples   Term_description   Term_description 0 :...   Term_description   Term_description 0 :...   Term_description   Term_description 0 :...   Particle_description   Term_description ...   Particle_quantity   Term_quantity 0 :...   Particle_quantity   Term_quantity 0 :...   Term_sequence   Term_description0 :...   Particle_sequence   Term_description0,0...   Use_sku   Use_sku 0 : AT("sku") Use_...   Use_sku   Use_sku 0 : AT("sku") Use_...   ProtoG_ProductElement   Use_color 0 :...   ProtoG_OrderElement   Term_prod... G.2 Normalized Grammar Examples   NormG_ProductElement Event Code Use_col...   NormG_ProductElement Event Code Use_col... G.3 Complete Grammar Examples   CompleteG_ProductElement Event Code Use...   CompleteG_ProductElement Event Code Use... H Recent Specification Changes (Non-Normative) H.1 Changes from Third Public Working Draft H.2 Changes from Second Public Working Draft H.3 Changes from First Public Working Draft I Acknowledgements (Non-Normative)
or

Refinement of the section concerned:

Status:

open proposal pending resolved_yes resolved_no resolved_partial other assigned to Nobody Bournez, Carine Brutzman, Don Cokus, Michael Fernández, Javier D. Heuer, Joerg Käbisch, Sebastian Kamiya, Takuki Kuntschke, Richard Matsukura, Ryuichi McGregor, Don Peintner, Daniel Quin, Liam Shah, Grishma ZERGAOUI, Mohamed

Type: substantive editorial typo question general comment undefined

Resolution status:

Response drafted Resolution implemented Reply sent to commenter

Response status:

No response from Commenter yet Commenter approved disposition Commenter objected to disposition
Commenter's response (URI):

Comment:

Dear EXI WG,

In 7.1 Built-in EXI Datatype Representations,
what do you think about the addition of IEEE float ?
For examples, it takes more time to decode EXI integer
because it isn't same to int type of general programing languages.

--
Regards,
Hitoshi Uchida
<uchida.hitoshi@canon.co.jp>

Related issues: 2104
(space separated ids)

WG Notes:

Resolution: We understand that the IEEE float representation is one of the most frequently requested changes to the EXI specification. We would like to use this opportunity to better explain our position on this issue and share with you the rationale that supports it. As you will find outlined below, the WG had assessed both its advantages and disadvantages in the context of EXI, as well as alternative ways to assuage the concerns. The WG came to believe that the use of IEEE float fits better with the user-defined datatype representation capability [1] of EXI than is integrated as an additional mandatory physical representation of character information items that are typed as xsd:float or xsd:double. There are some aspects of IEEE float that do not lend natureally themselves to the primary role of EXI as an efficient exchange format of XML, particularly when EXI is required to remain intrinsically compatible with existing XML family of standards written to XML infoset, such as XML signatures. The issues the WG looked at in particular are, less compactness and less amenability to compression, as well as rounding issues in serialization (base-2 to base-10) and the cost of stringification required when used with the typical XML APIs (SAX, DOM, etc.) which are undeniably predominantly text-based. However, by saying this, it is not our intention to derogate the value nor it is to neglect its wide-spread use in diverse range of applications. We do not intend to dispute the merit IEEE float brings to some applications, and understand EXI might be seen as the perfect opportunity to see that merit in a way fitted well to XML technologies. Though the EXI spec calls for a deliberate assessment when considering the use of user-defined datatype representation, obviously IEEE is one of such cases that warrant the use of the facility without any question. It was not an easy discussion within the WG that led to the position mentioned above. Some argued EXI is not XML enough, and others contended EXI as not binary enough. We respected both views to find a difficult balance and better serve both needs. In a way, we do not see EXI as static, rather it is a core foundation on which things can be further built to suit use cases, which will make the use of EXI more perfect. The two notable points of innovation provided by EXI are user-defined datatype representation, and the provision that permits the definition of schema binding for other schema languages. We therefore encourage you to seek the best way to leverage user-defined datatype definitions to represent float and double data as IEEE floats. If you find any suggestions that would make it easier to use IEEE float through user-defined datatype representation, we would love to hear them. Such suggestion may well find its way into a collateral documents such as FAQ or Best Practices. [1] http://www.w3.org/TR/exi/#datatypeRepresentationMap

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