state diagram

[Jeanne Boyarsky]

I am used to seeing something like this as a state diagram:

image from http://upload.wikimedia.org/wikipedia/commons/b/bc/Mealymachine_jaredwf.png

"Think Python" uses state diagram to mean the states of the variables. Where does this later use come from? Does either diagram have an alternate name?

[Allen Downey]

Hi Jeanne,

"State diagram" has several meanings in different contexts. The diagram you showed is a finite state machine. In UML, a state diagram usually shows the states of an interactive system and the events that cause transitions between states.

In Think Python I use the term in a slightly non-standard way, to refer to a diagram that shows the state of a running program. In UML it would be called an object diagram, but at the point in the book where I introduce state diagrams, we don't know about objects yet.

Allen