- From: Brandon A Born <baborn@sei.cmu.edu>
- Date: Wed, 30 Aug 2023 20:23:53 +0000
- To: "public-exi-comments@w3.org" <public-exi-comments@w3.org>
- Message-ID: <CA3E39D2-E7E7-46AC-87CC-15BC36C51ED6@contoso.com>
Good Afternoon, I am just doing some R&D on sending XML messages between systems using EXI. After working with a number of EXI processors and some internal code, I have a question about the EXI specification that seems different between the specification and primer. Specifically: the order of AT events in schema informed. The main document gave me the impression that they should be sorted lexicographical but the primer to me sounds like they must be lexicographical. The Specification: https://www.w3.org/TR/exi/#informedGrammars “Otherwise, when the grammar in effect is a schema-informed element grammar or a schema-informed type grammar (see 8.5.4 Schema-informed Element and Type Grammars), the remaining attributes can occur in any order that is permitted by the grammar, though in practice they SHOULD occur in lexicographical order sorted first by qname local-name then by qname uri for achieving better compactness, where a qname is a qname of an attribute.” The Primer: https://www.w3.org/TR/exi-primer/#schemaInformedGrammar Note that AT(category) is accepted before AT(date) even though their order is reversed in the schema. This is because attributes in schema-informed grammars must be sorted lexicographically, first by local name and then by namespace URI. Attribute sorting reduces the number of options which, in turn, greatly simplifies grammar creation and improves compactness. Since this automaton does not include transitions on AT(*) or SE(*), any deviations from the schema will result in an encoding error. Just wondering if this is my misunderstanding or just a difference in the documentation. Thank you, Brandon Brandon Born Carnegie Mellon Software Engineering Institute Software Solutions Division (SSD) Tactical and AI-Enabled Systems Initiative (TAS) 4500 Fifth Ave. Pittsburgh, PA 15213 Phone: (412) 268-4824
Received on Friday, 1 September 2023 10:28:59 UTC