Procedures

PROCEDURE proecdure-name signature "="
  declarations
  BEGIN
    statements
  END procedure-name ";"

procedure-name = identifier

A procedure declaration is composed of an identifier, a signature (see section Procedure Types), optional local declarations, and statements. The identifier at the end of the procedure must match the id at the beginning. Declarations made in a procedure are local to the procedure: they exist only while the procedure is executing.

If the procedure signature specifies a result type, the procedure is called a function procedure, and it must include a RETURN statement which returns an expression of the specified type. It is a checked runtime error for a function procedure to fail to return a result.

Example

PROCEDURE Hello( ) = 
  BEGIN
    IO.Put ("Hello World\n");
  END Hello;

PROCEDURE Check(f: File.T) RAISES { Problem } =
  BEGIN
    IF file = NIL THEN RAISE Problem END;
  END Check;

EXCEPTION Problem;