Atom配信フォーマット（Appendix B）

   This appendix is informative.

   The Relax NG schema explicitly excludes elements in the Atom
   namespace that are not defined in this revision of the specification.
   Requirements for Atom Processors encountering such markup are given
   in Sections 6.2 and 6.3.

   # -*- rnc -*-
   # RELAX NG Compact Syntax Grammar for the
   # Atom Format Specification Version 11

   namespace atom = "http://www.w3.org/2005/Atom"
   namespace xhtml = "http://www.w3.org/1999/xhtml"
   namespace s = "http://www.ascc.net/xml/schematron"
   namespace local = ""

   start = atomFeed | atomEntry

   # Common attributes

   atomCommonAttributes =
      attribute xml:base { atomUri }?,
      attribute xml:lang { atomLanguageTag }?,
      undefinedAttribute*

   # Text Constructs

   atomPlainTextConstruct =
      atomCommonAttributes,
      attribute type { "text" | "html" }?,
      text

   atomXHTMLTextConstruct =
      atomCommonAttributes,
      attribute type { "xhtml" },
      xhtmlDiv

   atomTextConstruct = atomPlainTextConstruct | atomXHTMLTextConstruct

   # Person Construct

   atomPersonConstruct =
      atomCommonAttributes,
      (element atom:name { text }
       & element atom:uri { atomUri }?
       & element atom:email { atomEmailAddress }?
       & extensionElement*)

   # Date Construct

   atomDateConstruct =
      atomCommonAttributes,
      xsd:dateTime

   # atom:feed

   atomFeed =
      [
         s:rule [
            context = "atom:feed"
            s:assert [
               test = "atom:author or not(atom:entry[not(atom:author)])"
               "An atom:feed must have an atom:author unless all "
               ~ "of its atom:entry children have an atom:author."
            ]
         ]
      ]
      element atom:feed {
         atomCommonAttributes,
         (atomAuthor*
          & atomCategory*
          & atomContributor*
          & atomGenerator?
          & atomIcon?
          & atomId
          & atomLink*
          & atomLogo?
          & atomRights?
          & atomSubtitle?
          & atomTitle
          & atomUpdated
          & extensionElement*),
         atomEntry*
      }

   # atom:entry

   atomEntry =
      [
         s:rule [
            context = "atom:entry"
            s:assert [
               test = "atom:link[@rel='alternate'] "
               ~ "or atom:link[not(@rel)] "
               ~ "or atom:content"
               "An atom:entry must have at least one atom:link element "
               ~ "with a rel attribute of 'alternate' "
               ~ "or an atom:content."
            ]
         ]
         s:rule [
            context = "atom:entry"
            s:assert [
               test = "atom:author or "
               ~ "../atom:author or atom:source/atom:author"
               "An atom:entry must have an atom:author "
               ~ "if its feed does not."
            ]
         ]
      ]
      element atom:entry {
         atomCommonAttributes,
         (atomAuthor*
          & atomCategory*
          & atomContent?
          & atomContributor*
          & atomId
          & atomLink*
          & atomPublished?
          & atomRights?
          & atomSource?
          & atomSummary?
          & atomTitle
          & atomUpdated
          & extensionElement*)
      }

   # atom:content

   atomInlineTextContent =
      element atom:content {
         atomCommonAttributes,
         attribute type { "text" | "html" }?,
         (text)*
      }

   atomInlineXHTMLContent =
      element atom:content {
         atomCommonAttributes,
         attribute type { "xhtml" },
         xhtmlDiv
      }

   atomInlineOtherContent =
      element atom:content {
         atomCommonAttributes,
         attribute type { atomMediaType }?,
         (text|anyElement)*
      }

   atomOutOfLineContent =
      element atom:content {
         atomCommonAttributes,
         attribute type { atomMediaType }?,
         attribute src { atomUri },
         empty
      }

   atomContent = atomInlineTextContent
    | atomInlineXHTMLContent
    | atomInlineOtherContent
    | atomOutOfLineContent

   # atom:author

   atomAuthor = element atom:author { atomPersonConstruct }

   # atom:category

   atomCategory =
      element atom:category {
         atomCommonAttributes,
         attribute term { text },
         attribute scheme { atomUri }?,
         attribute label { text }?,
         undefinedContent
      }

   # atom:contributor

   atomContributor = element atom:contributor { atomPersonConstruct }

   # atom:generator

   atomGenerator = element atom:generator {
      atomCommonAttributes,
      attribute uri { atomUri }?,
      attribute version { text }?,
      text
   }

   # atom:icon

   atomIcon = element atom:icon {
      atomCommonAttributes,
      (atomUri)
   }

   # atom:id

   atomId = element atom:id {
      atomCommonAttributes,
      (atomUri)
   }

   # atom:logo

   atomLogo = element atom:logo {
      atomCommonAttributes,
      (atomUri)
   }

   # atom:link

   atomLink =
      element atom:link {
         atomCommonAttributes,
         attribute href { atomUri },
         attribute rel { atomNCName | atomUri }?,
         attribute type { atomMediaType }?,
         attribute hreflang { atomLanguageTag }?,
         attribute title { text }?,
         attribute length { text }?,
         undefinedContent
      }

   # atom:published

   atomPublished = element atom:published { atomDateConstruct }

   # atom:rights

   atomRights = element atom:rights { atomTextConstruct }

   # atom:source

   atomSource =
      element atom:source {
         atomCommonAttributes,
         (atomAuthor*
          & atomCategory*
          & atomContributor*
          & atomGenerator?
          & atomIcon?
          & atomId?
          & atomLink*
          & atomLogo?
          & atomRights?
          & atomSubtitle?
          & atomTitle?
          & atomUpdated?
          & extensionElement*)
      }

   # atom:subtitle

   atomSubtitle = element atom:subtitle { atomTextConstruct }

   # atom:summary

   atomSummary = element atom:summary { atomTextConstruct }

   # atom:title

   atomTitle = element atom:title { atomTextConstruct }

   # atom:updated

   atomUpdated = element atom:updated { atomDateConstruct }

   # Low-level simple types

   atomNCName = xsd:string { minLength = "1" pattern = "[^:]*" }

   # Whatever a media type is, it contains at least one slash
   atomMediaType = xsd:string { pattern = ".+/.+" }

   # As defined in RFC 3066
   atomLanguageTag = xsd:string {
      pattern = "[A-Za-z]{1,8}(-[A-Za-z0-9]{1,8})*"
   }

   # Unconstrained; it's not entirely clear how IRI fit into
   # xsd:anyURI so let's not try to constrain it here
   atomUri = text

   # Whatever an email address is, it contains at least one @
   atomEmailAddress = xsd:string { pattern = ".+@.+" }

   # Simple Extension

   simpleExtensionElement =
      element * - atom:* {
         text
      }

   # Structured Extension

   structuredExtensionElement =
      element * - atom:* {
         (attribute * { text }+,
            (text|anyElement)*)
       | (attribute * { text }*,
          (text?, anyElement+, (text|anyElement)*))
      }

   # Other Extensibility

   extensionElement =
      simpleExtensionElement | structuredExtensionElement

   undefinedAttribute =
     attribute * - (xml:base | xml:lang | local:*) { text }

   undefinedContent = (text|anyForeignElement)*

   anyElement =
      element * {
         (attribute * { text }
          | text
          | anyElement)*
      }

   anyForeignElement =
      element * - atom:* {
         (attribute * { text }
          | text
          | anyElement)*
      }

   # XHTML

   anyXHTML = element xhtml:* {
      (attribute * { text }
       | text
       | anyXHTML)*
   }

   xhtmlDiv = element xhtml:div {
      (attribute * { text }
       | text
       | anyXHTML)*
   }

   # EOF