EvaluableExpression.go
func (this EvaluableExpression) Vars() []string {
	var varlist []string
	for _, val := range this.Tokens() {
		if val.Kind == VARIABLE {
			varlist = append(varlist, val.Value.(string))
		}
	}
	return varlist
}
func (this EvaluableExpression) Vars() []string {
	var varlist []string
	for _, val := range this.Tokens() {
		if val.Kind == VARIABLE {
			varlist = append(varlist, val.Value.(string))
		}
	}
	return varlist
}
/*
	Returns an array representing the variables contained in this EvaluableExpression.
*/