Cwm (pronounced coom) is a general-purpose data processor for the semantic web, somewhat like sed, awk, etc. for text files or XSLT for XML. It is a forward chaining reasoner which can be used for querying, checking, transforming and filtering information. Its core language is RDF, extended to include rules, and it uses RDF/XML or RDF/N3 serializations as required.
Cwm is written in python; it is part of SWAP, a Semantic Web Application Platform. It is open source under the W3C software license.