Cω is an extended CeeSharp variant supporting SemanticSubtyping with XML and relational datatypes, and concurrency abstractions based on the JoinCalculus - the mutant offspring of MicrosoftXen and PolyphonicCeeSharp. The language name is capital C, lowercase Greek omega.

There's a downloadable preview (requires VisualStudio .Net 2003), available at http://research.microsoft.com/Comega/, and some documentation, at http://research.microsoft.com/Comega/doc/comega_startpage.htm

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Originally at MicrosoftXen, about the typing features:

''I believe it is a research lab creation to demonstrate OoAndXml can co-exist, and that OoVsRelational is a nonissue [ObjectRelationalImpedanceMismatchDoesNotExist].''

''See ''Programming with Rectangles, Triangles, and Circles'' at http://lambda-the-ultimate.org/classic/message9178.html''
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See also the discussion of the JoinCalculus at ActorsModel.
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CategoryProgrammingLanguage CategoryMicrosoft