"Aero Snap" (sort of) in FVMW

I really like Windows 7's "Aero Snap" feature. I never drag windows, but I use Win+Left/Right all the time, and it really bugs me when I use another system and it doesn't do anything.

Here's how to do it in FVWM:
AddToFunc LeftHalf
+ I Move 0 0
+ I Maximize 50 100
+ I Raise
AddToFunc RightHalf
+ I Maximize 50 100
+ I Move 50 0
+ I Raise
Key Left A 4 LeftHalf
Key Right A 4 RightHalf

FVWM will remember the old window size for you (but will follow your window placement rules when positioning it).