Allows an expression to be passed in as a parameter without immediatly being evaulated.

This class represents a FlexScript expression. Functions that accept these values store the expression passed in as a parameter, rather than the result of the expression. The function may evaluate the expression one or more times. During evaulation, the keyword count may be used to determine how many times the expression has been called. One method that accepts lambdas as parameters is the Table.query() method.