plt/racket — pull request #604 by takikawa (2014-03-27 02:41:16+00:00)
Title: Type expanders for TR

This PR adds type expanders ala match expanders to TR.

I implemented this so I could add a shorthand notation for mixin types. See the second commit.

This still needs tests and docs, but I thought I'd run it by to see if (1) people thought this was a good addition at all, and (2) that the design looks palatable.