DITAisanarchitectureforcreating topic-oriented,information-typedcontentthatcanbe reusedand single-sourcedina varietyofways. Itisalso anarchitectureforcreatingnew topictypesand describing newinformationdomainsbased onexistingtypesand domains.
Theprocessforcreatingnew topictypesand domainsiscalledspecialization.Specializationallowsthe creationofveryspecific,targeteddocumenttypedefinitionswhilestillsharingcommonoutput
transformsanddesignrulesdevelopedfor moregeneraltypesanddomains,inmuchthesame waythat classesinan object-orientedsystemcaninheritmethodsofancestorclasses.
DITAtopics areXMLconforming.Assuch,they arereadilyviewed,edited,and validatedwith standard XMLtools,althoughsomefeaturessuchascontentreferencingandspecializationmaybenefitfrom customizedsupport.
Definitions and background concepts
Thefollowingtermshavespecificmeanings inDITAwhichshouldbeunderstoodbeforereadingeither theDITAmarkupspecificationortheDITAspecializationspecification.
Basic concepts
ThefollowingarebasicconceptsusedinDITA.
“Whataretopics?”onpage7
Atopicisaunitofinformationwith atitleandcontent,shortenoughtobe specifictoasingle subject oranswera singlequestion,butlongenoughtomakesenseonitsownand beauthoredasa unit.
“Whataremaps?”onpage14
DITAmapsaredocumentsthatcollectand organizereferencestoDITAtopics toindicatethe relationshipsamongthetopics.They canalsoserveasoutlinesortablesof contentsforDITA deliverablesand asbuildmanifestsforDITAprojects.
“Whatisspecialization?”onpage27
Specialization allowsyoutodefinenewkindsofinformation(newstructural typesornew domainsof information),whilereusingasmuchofexistingdesignandcodeaspossible,andminimizingor eliminatingthecostsofinterchange,migration,andmaintenance.
“Structural versusdomainspecialization”onpage28
Structuralspecializationdefinesnewtypesofstructuredinformation,suchasnewtopictypesornew maptypes.Domainspecializationcreatesnewmarkupthatcanbeusefulinmultiple structuraltypes, suchasnewkindsofkeywords,tables, orlists.
“Integration”onpage35
Eachdomainspecializationorstructuralspecializationhasitsown designmodule.Thesemodulescan be combinedtocreatemanydifferentdocumenttypes.Theprocess ofcreatinganew documenttype froma specificcombinationofmodules iscalled integration.
“Customization”onpage42
Whenyoujustneeda differenceinoutput,youcanuseDITAcustomizationtooverridethedefault outputwithoutaffectingportabilityorinterchange,and withoutinvolvingspecialization.
“Generalization”onpage33
Specializedcontentcanbe generalizedtoanyancestor type.Thegeneralizationprocess canpreserve informationabouttheformerlevelofspecializationto allowround-tripping betweenspecializedand unspecializedformsofthesamecontent.
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Terminology
DITAusesa numberoftermsinparticularoruniqueways. Withinthescopeofthisspecification,the followingtermsareusedwhentalking aboutDITAmodels,DITAdeclarations,andDITAinstances.
Model terminology
DITAcanbe understoodat thelevelofanabstractmodelwithoutreferencetoparticularDTDs,schemas, oractualXMLdocuments.WhendiscussingDITAconceptsatthislevel, thefollowingterminologyis used.
Elementtype
Definesthestructureandsemantics forafragmentofcontent.
Specializedelementtype
Definesanelementtypeasasemanticrefinementofanotherelementtype.Thecontentallowed bythespecializedelementtype mustbea subsetoforidenticaltothecontentallowedbythe originalelementtype.
Topictype
Anelementtypethatdefinesacompleteunitofcontent.Thetopictypeprovides therootelement forthetopic and,throughcontainedelementtypes,substructureforthetopicinstances. Theroot elementofthetopictype isnotnecessarilythesameastherootelementofadocumenttype:
documenttypesmaynestmultiple topictypes,and mayalsodeclarenon-DITAwrapperelements astherootelementforcompatibilitywithotherprocesses.
Maptype
Anelementtypethatdefinesaset ofrelationshipsfortopicinstances. Themaptype providesthe rootelementand,through containedelementtypes,substructureforthemapinstances.Themap substructureprovideshierarchy,group,andmatrixorganizationofreferencestotopicinstances.
Structuraltype
Atopic typeormaptype.
Domain
Aset ofelementsthatsupporta specificsubjectarea.Elementsinadomaincanbeintegrated withtopicormaptypestoenhancetheirsemanticsupportforparticularkindsofcontent.For example,thestructural type<topic>declaresthe<keyword>element; whenintegratedwitha domainfordescribinguserinterfaces, newkeywordspecializations (suchas<wintitle>)become availablewherever<keyword>wasallowed intheoriginalstructuraltype.
Documenttype
Thefullset ofelementtypesdefinedinthemodulesthatareintegratedbythedocumenttype shell.ADITAdocumenttypemaysupport authoringmultiple topictypesormultiple maptypes, butnotamixofthetwo.The structuraltypescanbe augmentedwithelementsfromdomains.
Theterm″documenttype″isusedforcompatibilitywith existingstandards,since thisisthepoint atwhichDITA’ssetoftopic,domain,andmaptypesareassembledintoa documenttypethatis functionallyequivalenttoatraditionalnon-modularizeddocumenttype.
Declaration terminology
WhenthemodelisexpressedinaDTDorschema, thevariouselementtypesaredeclared.When referringtothesedeclarations, thefollowingterminologyisused.
Elementdeclaration
Therepresentationwithin aschematechnology(suchasDTD, XMLSchema,orRelaxNG)foran elementtype.
Typemodule
Therepresentationwithin aschematechnologyfortheelementtypesuniquelydefinedbyatopic type,maptype, ordomain.
Topicmodule
Therepresentationwithina schematechnology fortheelementtypesuniquelydefinedbyatopic type.
Mapmodule
Therepresentationwithina schematechnology fortheelementtypesuniquelydefinedbyamap type.
Structuralmodule
Atopicor mapmodule.
Domainmodule
Therepresentationwithina schematechnology fortheelementtypesuniquelydefinedbya domain.
Documenttypeshell
Therepresentationwithina schematechnology forashellthatdeclaresnoelementtypesitself butpointstoand assemblestopic,map,and domainmodules.
Documenttypedeclaration
Therepresentationwithina schematechnology foradocumenttype.The documenttype declarationincludesthedeclaration modulesassembledbythedocumentdeclarationshell.
Instance terminology
Whenactualdocuments,topics,and elementsarecreatedbasedona DITAdocumenttype,thefollowing terminologyisused.
Elementinstance
Anoccurrenceofanelementtypeina document.
Topicinstance
Anoccurrenceofatopictype inadocument.
Mapinstance
Anoccurrenceofamaptypeina document.
Structuraltypeinstance
Anoccurrenceofatopictype oramaptypeina document.
Documentinstance
Adocumentwhosemeaningand validityaredeterminedbyadocumenttypedeclaration.
Naming conventions and file extensions
Thefollowingnamingconventions andfileextensionsareinusebyDITA.
DITAtopicinstancefiles
*.xml,*.dita DITAmapinstancefiles
*.ditamap
DTDstructuralmodule files typename.mod
DTDdomainmodulefiles typenameDomain.mod typenameDomain.ent Schemastructuralmodulefiles
typenameMod.xsd typenameGrp.xsd
Chapter2.AnintroductiontoDITA 5
Schemadomainmodule files typenameDomain.xsd CSSoverridefiles
typename.css
customization-purpose.css XSLToverridefiles
typename.xsl
customization-purpose.xsl