diagrams/diagrams-core — pull request #52 by byorgey (2014-02-08 21:16:16+00:00)
Title: Introduce Typeable constraint on Prims (see #42)

Requires things wrapped in `Prim` to have a `Typeable` instance, making it possible to extract things out of a `Prim` wrapper if you know what type you want. We may also want to provide some convenience methods for doing such extraction, but we can do that separately from this PR.