hadley/plyr — pull request #97 by wch (2012-10-09 14:45:10+00:00)
Title: Fixes for mapvalues() and revalue()

This does the following :

* `mapvalues` checks if the input is atomic.
* `revalue` can handle NULL (it just returns NULL). This makes `rename()` able to handle empty vectors and lists (as it could do in the previous plyr release), which in turn fixes an issue in `ggplot2::rename_aes()`.
* Added tests for these things.