diagrams/dual-tree — pull request #1 by byorgey (2012-09-03 01:57:35+00:00)
Title: dual-tree rewrite

This is a complete rewrite of dual-tree based on insights I had while writing my paper "Monoids: Theme and Variations". I think this version is much simpler and more regular, and should make possible some new extensions to diagrams and better support for backends to be able to observe the tree structure of diagrams. This set of commits also includes some basic tests.

Note: these commits depends on this pull request for `monoid-extras`: https://github.com/diagrams/monoid-extras/pull/1 . A corresponding pull request to fix up `diagrams-core` to work with this rewritten version of `dual-tree` will follow shortly. No changes to anything further up the stack (`diagrams-lib`, `diagrams-cairo`, `diagrams-contrib`...) are necessary.