EBNF is a Ruby parser for W3C EBNF and a parser generator for PEG and LL(1). Also includes parsing modes for ISO EBNF and ABNF.

SPARQL Implements SPARQL 1.1 Query, Update and result formats for the Ruby RDF.rb library suite.

RDF::N3 is an Notation-3 reader/writer and reasoner for the RDF.rb library suite.

Implements ShExC and ShEx JSON.

Implements the W3C Linked Data Patch Format and operations for RDF.rb. Makes use of the SPARQL gem for performing updates.

SHACL is an Shape Constraint engine for the Ruby RDF.rb library suite.

A Scheme interpreter in Ruby

YARSPG is an YARS-PG reader/writer for the RDF.rb library suite.

Yet another OWL documentor. YOWL is a command line utility that can read a number of RDFS/OWL files, called the repository, and generate a documentation website from it, with visualisations like Class Diagrams (as SVG), Individuals Diagrams and Import Diagrams.