RaCTPP is a Ruby wrapper for FaCT++, a SROIQ(D) description logic reasoner, with support for OWL DL and partial support for OWL 2.0. RaCTPP is intended to be used as a reasoner for the Web Ontology Language (OWL) in Semantic Web and Linked Data applications. The API is based on the Java-FaCT++ JNI bridge by Dmitry Tsarkov.
First of all, it's not 100% Ruby. It's a Ruby extension built in C++ that links in to the FaCT++ library, which itself is C++. One day, I'd like to build a 100% pure Ruby OWL reasoner, but that's significantly more effort and just not in the cards at the moment.
It's also not a parser. Although, it could easily work with a parser and probably should. There's a great 100% pure Ruby parser for the many RDF syntaxes (RDF/XML, Turtle, N3, etc.), which could certainly be adapted to work with this tool, and that's my next project. I don't have a plan to implement a parser for the OWL abstract syntax or Manchester syntax at the moment.
RaCTPP is licenced under the Lesser GNU Public Licence. For more information, see the COPYING and COPYING.LESSER files. RactPP is written and maintained by Jonathan Abourbih (jon.abourbih+github@gmail.com).
You'll need:
- Ruby 1.9.2
- bundler (
gem install bundler) - gcc, g++, and make. I've tested this with gcc 4.2.1 on the Mac, with the latest version of XCode.
Now, to build the project:
- Download the FaCT++ source code (tested with version 1.5.0)
- Modify the FaCT++ Makefile according to their instructions for your platform
- Build the Kernel using
make kernel, making a note of the location of thesrc/Kerneldirectory. You don't need to build any of the other stuff, and it's probably best you don't if you have a Mac, as the JNI stuff is totally broken now.
Now, back to this project. Install the required rubygems with:
$ bundle install
Then, use the Rakefile to build the project, specifying the location of the FaCT++ Kernel:
$ rake compile FACT_KERNEL_DIR=/path/to/FaCT++-1.5.0/src/Kernel
And finally, run the RSpec tests:
$ rake spec
According to Wikipedia, a description logic is a member of a logic family that can be used to describe a knowledge domain. Description logics are typically subsets of first-order predicate logic, but are more efficient for reasoning and more expressive than propositional logic. Description logics may be used to build ontologies, which computers can use to reason and make inferences over a domain.
OWL is a W3C standard language for the Semantic Web. OWL is compatible with RDF, the Resource Description Framework, which is frequently used as a serialisation.
The Semantic Web is an extension of the current one, in which information is given well-defined meaning, better enabling computers and people to work in cooperation. The Semantic Web, Berners-Lee et. al., 2001
The Semantic Web has seen explosive growth over the past few years, especially since the start of the Linked Data project. Linked Data semantically relates data from different, disparate data sources using shared vocabulary. Rather than being a standard, it's more of a best practice for sharing data.