You were probably having the dreaded "Maint Req'd" Light on your dash before the hose separated. The plastic would have cracked first and your EVAP System would not work properly. It looks like you can remove the broken piece from the hose and install a replacement EVAP unit to allow you to get back to spec.
This is also a good message for others to check that connection on their cars to assure there is no crack there.
P.S. The "Oil Sensor" electrical connector will also crack and allow oil to trail into your Distributor Cap. Check that as well.