[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: XML Schema and Entities
"Bullard, Claude L (Len)" wrote: > > The XML Schema Primer is not very clear with respect to the > use of entities in XML Schema. I realize the need to use > the DTD and internal subset, the food chain of resolution > prior to invoking the schema engine, the use of Group over > parameter entities, but what is done with type="xsd:entities" > or type="xsd:entity" in the XML Schema? I see the note about > using them only in attributes, but still, there isn't an example > that clarifies what they are good for in the Schema. Part 2 is clearer about them [1]: [1] http://www.w3.org/TR/xmlschema-2/#ENTITY "[Definition:] ENTITY represents the ENTITY attribute type from [XML 1.0 (Second Edition)]. The ·value space· of ENTITY is the set of all strings that ·match· the NCName production in [Namespaces in XML] and have been declared as an unparsed entity in a document type definition. The ·lexical space· of ENTITY is the set of all strings that ·match· the NCName production in [Namespaces in XML]. The ·base type· of ENTITY is NCName. " They are therefore as good for W3C XML Schema as unparsed entities are for DTDs :=) ... Personally I have never seen them used except in Simon St.Laurent "elements of style" (a book that I recommend not only for this example ;=) ) where he gives the following example that could be used with a W3C XML Schema defining that the content attribute has a type "ENTITY": <!DOCTYPE unparsed_image SYSTEM "unparsed_image.dtd" [ <!ENTITY myGif "mygif.gif" NDATA image_gif> ]> <unparsed_image content="myGif"/> Hope this helps. Eric > Len > http://www.mp3.com/LenBullard > > Ekam sat.h, Vipraah bahudhaa vadanti. > Daamyata. Datta. Dayadhvam.h > -- Pour y voir plus clair dans la nebuleuse XML... http://dyomedea.com/formation/ ------------------------------------------------------------------------ Eric van der Vlist http://xmlfr.org http://dyomedea.com http://xsltunit.org http://4xt.org http://examplotron.org ------------------------------------------------------------------------
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