The entire OCL language has a small set of keywords. We've already seen invariant, pre, and post. There's an if-then-else if you need that to, describe conditional expressions.
There are Boolean operators. There's a packaging mechanism that reflects UML's ability to partition things into packages. The context keywords you've seen.
There's, several key words that allow you to do some definitions. Definitions can be useful to save you typing effort if define something to use the short version there's ability to indicate that your computing the value of derived attribute the derived key word. There's the ability to indicate that you're specifying an initial value, we, and we've already seen result and self.
