Tracking integer values?

[jjbrunton]

I am trying to use this library to track the increasing of an inventory count. For example, the user needs to collect wood to build a house:

• Precondition: hasAxe = true
• Effect: Wood += 1

And then another action:

• Precondition: wood >= 10
• Effect: Planks 2

But it doesn't seem possible to impact the world state from the constructor of an action, am I missing something simple?