Do syntax copy of an array of Statement's.
Determine if an enclosed break would apply to this statement, such as if it is a loop or switch statement.
Determine if an enclosed continue would apply to this statement, such as if it is a loop statement.
Find last statement in a sequence of statements.
Support Visitor Pattern
Does this statement end with a return statement?
A cheaper method of doing downcasting of Statements.
Any Statement that fails semantic() or has a component that is an ErrorExp or a TypeError should return an ErrorStatement from semantic().