eastein/dudemon — Issue #12: allow !here with arrival time in the past
Author: eastein
Created: 2012-02-20 01:35:15+00:00
State: open

As is, !here either says "I'm here now, you go ahead and guess how long I'll be here" or "hey, I'm here now and I'll be here for n hours".

A possibility should be to state the same things, but with the arrival point in the past. Perhaps using a `-` prefix on the first arg to indicate that it's how long one has been around:

!here -5

This would mean that the user's been around for 5 minutes. This introduces an issue if the user was scheduled for a 2 hour 'presence' and then states that they've been 'in' for 3 hours. Is the user really here? Does this cause an error? Can this error be worked around by providing a departure estimate, like so?

!here -3:00 1:00

This would indicate "I've been here for 3 hours, leaving in an hour."