View source for ShorthandRDF

= Shorthand RDF =

== History ==

The XML serialization of RDF is sufficiently verbose
that shorthand syntaxes naturally spring up in email,
IRC, and handheld devices.

e.g.

* Walsh, Norman, [http://nwalsh.com/docs/articles/extreme2002/ Generalized Metadata in your Palm], Proceedings of Extreme Markup Languages 2002, August 2002.
* [[NotationThree]]

While [[NotationThree]], a text editor, and a tool to convert
to RDF/XML work well for programmer types,
other [[AuthoringToolsForRDF]] generally work with more
direct-manipulation style of interaction.

----

Hmm... I'm not likely to use the colons when scribbling in my PDA.
Neither was norm. I like to write dates ala 7Apr2003. Hmm...


<pre><nowiki>
@namepattern "\d\d?[A-Z][a-z][a-z]\d\d\d\d" <http://www.w3.org/2002/12/cal/date#>.

<#thisEvent> cyc:startingDate 7Apr2003.
</nowiki></pre>


would work like


<pre><nowiki>
<#thisEvent> cyc:startingDate <http://www.w3.org/2002/12/cal/date#7Apr2003>.
</nowiki></pre>


or perhaps use datatypes...


<pre><nowiki>
@datatype "[+-]?\d+" <http://...#integer>.
@datatype "\d\d?[A-Z][a-z][a-z]\d\d\d\d" <http://www.w3.org/2002/12/cal/types#FriendlyDate>.

:lunch :price 20; :date 7Apr2003.
</nowiki></pre>


would work like


<pre><nowiki>
:lunch :price "20"^^<http://...#integer>;
  :date "7Apr2003"^^<http://www.w3.org/2002/12/cal/types#FriendlyDate>.
</nowiki></pre>

----

== RDF-TriN3 Implementation ==

I'm implementing this in [http://search.cpan.org/dist/RDF-TriN3/ RDF-TriN3] and hoping to converge on a stable syntax. RDF-TriN3 implements this on top of an N3 parser, though implementing an RDF-compatible subset on top of a Turtle parser would also be a useful goal.

RDF-TriN3 currently supports the following shorthand extensions to N3:

  @term token <uri> .
  @term token "literal" .
  @pattern "regexp" <uri_template> .
  @pattern "regexp" "literal template" .
  @dtpattern "regexp" <datatype_uri> .
  @namepattern "regexp" <uri_prefix> .
  @import <uri> .
  @profile <uri> .

=== @term ===

The shorthand '''@term token <uri>''' defines the token to be shorthand for the full URI <uri>. For example:

  @prefix foaf: <http://xmlns.com/foaf/0.1/> .
  @term called <http://xmlns.com/foaf/0.1/name> .
  @term Dude foaf:Person .
  @prefix foaf: <http://example.com/not-foaf/> . # doesn't effect previous definition!
  
  [] a Dude ; called "Toby Inkster" .

is equivalent to:

  @prefix foaf: <http://xmlns.com/foaf/0.1/> .
  
  [] a foaf:Person ; foaf:name "Toby Inkster" .

Terms (which are case-sensitive, like prefixes) can also be defined as literals:

  @term Zero "0"^^<http://example.com/unit/Kelvin> .
  
  :thing :temperature Zero .

=== @pattern ===

The shorthand '''@pattern "regexp" <uri_template>''' treats the provided plain literal as a pattern to match against tokens as a regular expression. 

  @pattern "(\d{2})-(\d{2})-(\d{4})" <http://example.com/day/$3/$2/$1> .
  
  [] :born 01-06-1980 .

is equivalent to:

  [] :born <http://example.com/day/1980/06/01> .

As is:

  @pattern "(?<d>\d{2})-(?<m>\d{2})-(?<y>\d{4})" <http://example.com/day/$y/$m/$d> .
  [] :born 01-06-1980 .

Or:

  @pattern "(?<d>\d{2})-(?<m>\d{2})-(?<y>\d{4})" <http://example.com/day/${y}/${m}/${d}> .
  [] :born 01-06-1980 .

Patterns can also expand to literals.

=== @namepattern and @dtpattern ===

'''@namepattern''' and '''@dtpattern''' are shortcut for things that could have been written out as '''@pattern''':

  @namepattern "\d\d?[A-Z][a-z][a-z]\d\d\d\d" <http://www.w3.org/2002/12/cal/date#> .

is shorthand for:

  @pattern "\d\d?[A-Z][a-z][a-z]\d\d\d\d" <http://www.w3.org/2002/12/cal/date#$0> .

And:

  @dtpattern "\d\d?[A-Z][a-z][a-z]\d\d\d\d" <http://www.w3.org/2002/12/cal/types#FriendlyDate> .

is shorthand for:

  @pattern "\d\d?[A-Z][a-z][a-z]\d\d\d\d" "$0"^^<http://www.w3.org/2002/12/cal/types#FriendlyDate> .

=== @import and @profile ===

'''@import''' essentially inlines an external N3, Turtle or Shorthand RDF file into the current file. It parses the file linked to, copies its triples into the current graph, and copies its terms, patterns and prefixes into the current parsing context. It does not alter the current parsing context's base URI. It cannot overwrite the empty prefix. It also adds this triple to the current graph:

  <> owl:imports <imported_uri> .

'''@profile''' performs a subset of '''@import'''. It just copies the terms, patterns and prefixes into the current parsing context. It does not add any triples to the current graph.

=== Resolution Order ===

Like '''@prefix''' and '''@base''', the last matching rule "wins".

As '''@base''' may occur several times in an N3 document, changing the base URI, it is important to note that any patterns and tokens which are defined in terms of a relative URI use the base URI at the time of their definition, not the time of their use. For example:

  @base <http://example.com/people/> .
  @pattern "\~(\S+)" <$1> .
  @base <http://example.com/documents/> .
  @pattern "Doc(\d+)" <$1> .
  @base <http://example.com/terms/> .
  
  Doc1234 <creator> ~tobyink .

Is equivalent to:

  <http://example.com/documents/1234>
      <http://example.com/terms/creator>
          <http://example.com/people/tobyink> .