if the following are true:

• the line at time t = i
• the tab at time t = j
• statement at line i, tab j = assign statement with target x and expression (obj.attr)
• Expression Stack at time t = [ [ ], [ ] ]
• Value Stack at time t = [ [ value, [ ] ], [ ] ]

then Variables Map at time (t + 1) = result of storing value at key: x in map: (Variables Map at time t)