buildbot/buildbot — pull request #522 by tardyp (2012-09-11 17:58:46+00:00)
Title: properties: add adapter for callables

it is a very common need for users just to want to create a
function to do the property interpolation.

one can now say:

Shell(command=lambda p:"echo next build is"+(p.getProperty("buildnumber")+1))