So I alluded to this in my About page and figured I would start there. <sarcasm> No better way to start a blog than on a light topic right? </sarcasm> (As a foreigner living in the UK I just want to be fair to everyone, so I’m being explicit - the bane of being a programmer.) So lets dig right in, what is this confusion I am even hoping to discuss?
In combinatorial logic, things are evaluated in parallel, with no particular order. Take a physical OR gate, as illustrated below. It has two inputs, A and B, and one output Q. This gate evaluates in real time. Just because you put an undefined signal (in the case of hardware this would mean it was neither 1 or 0, very possible by just leaving the input disconnected) into A, this does not stop the gate from considering B. Just for completeness, this means that the output would also not be concretely defined as 1 or 0.