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RDF::TriG reader/writer

TriG reader/writer for RDF.rb .


This is a Ruby implementation of a TriG reader and writer for RDF.rb.


RDF::TriG parses TriG into statements or quads. It also serializes to TriG.

Install with gem install rdf-trig

  • 100% free and unencumbered public domain software.
  • Implements a complete parser and serializer for TriG.
  • Compatible with Ruby 1.8.7+, Ruby 1.9.x, and JRuby 1.4/1.5.


Instantiate a reader from a local file:

repo = RDF::Repository.load("etc/doap.trig", :format => :trig)

Define @base and @prefix definitions, and use for serialization using :base_uri an :prefixes options.

Canonicalize and validate using :canonicalize and :validate options.

Write a repository to a file:"etc/test.trig") do |writer|
   writer << repo

Note that reading and writing of graphs is also possible, but as graphs have only a single context, it is not particularly interesting for TriG.


Full documentation available on

Principle Classes

  • {RDF::TriG::Format}
  • {RDF::TriG::Reader}
  • {RDF::TriG::Writer}

Interpretations of the spec

It is still not defined what the interpretation of multiple uses of the same graphIri mean. This implementation takes the use of multiple graphs having the same graphIri to be additive, meaning that the statements from each graph are combined together to create a single graph.

Graphs are written with context set to the associated graphIri.

Although RDF::Repository allows any RDF::Value, such as a BNode, literal or variable to be used as a context, TriG only allows the use of an IRI.

Implementation Notes

The reader uses the Turtle parser, which is based on the LL1::Parser with minor updates for the TriG grammar. The writer also is based on the Turtle writer.



The recommended installation method is via RubyGems. To install the latest official release of the RDF::TriG gem, do:

% [sudo] gem install rdf-trig

Mailing List



  • Do your best to adhere to the existing coding conventions and idioms.
  • Don't use hard tabs, and don't leave trailing whitespace on any line.
  • Do document every method you add using YARD annotations. Read the tutorial or just look at the existing code for examples.
  • Don't touch the .gemspec, VERSION or AUTHORS files. If you need to change them, do so on your private branch only.
  • Do feel free to add yourself to the CREDITS file and the corresponding list in the the README. Alphabetical order applies.
  • Do note that in order for us to merge any non-trivial changes (as a rule of thumb, additions larger than about 15 lines of code), we need an explicit public domain dedication on record from you.


This is free and unencumbered public domain software. For more information, see or the accompanying {file:UNLICENSE} file.

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