The statement is used to define loops which are executed a condition is true (not true, which is more common in other languages). It is also used to call procedures or ranges of procedures (see the procedures section for more details). and call subprograms and methods, respectively. The name of the subprogram/method is contained in a string which may be a literal or a data item. Parameters can be passed by reference, by content (where a copy is passed by reference) or by value (but only if a prototype is available).