A new version of Collections was added to project The Inbox:
http://source.squeak.org/inbox/Collections-cbc.582.mcz

==================== Summary ====================

Name: Collections-cbc.582
Author: cbc
Time: 13 September 2014, 10:10:32.637 pm
UUID: 8d429e7d-5779-5d48-aabe-139fb9239592
Ancestors: Collections-nice.580

Changes to support adding months and years to a DateAndTime, such as:
DateAndTime now + 2 months
and
DateAndTimeNow - 5 years

This requires retro-fitting the + and - in DateAndTime to a double dispatch system.

This part is for String support; the main changes are in Kernel-cbc.870.

=============== Diff against Collections-nice.580 ===============

Item was added:
+ ----- Method: String>>addToDateTime: (in category 'converting') -----
+ addToDateTime: aDateAndTime
+ 	^self asDuration addToDateTime: aDateAndTime
+ !