Declarations Examples

CONST
        Pi = 3.14;              (* REAL *)
        Maxsize = 30;           (* INTEGER *)
        Space = ' ';            (* CHAR *)

TYPE
        Index = [1..Maxsize];                   (* Subrange *)
        Letters = ['a'..'z'];                   (* Subrange *)
        Colors = {Red, Green, Blue, Yellow};    (* Enumerated *)
        ArrType = ARRAY Colors OF INTEGER;      (* ARRAY *)
        ArrType2 = ARRAY [1..5] OF CHAR;        (* ARRAY *)
        SetType = SET OF Letters;               (* SET *)
        Ptr = REF Student;                      (* Pointer *)
        Student = RECORD                        (* RECORD *)
           name : TEXT;
           id   : INTEGER;
           gpa  : REAL;
           next : Ptr;
        END;

VAR
        n       : INTEGER       := -15;                 (* INTEGER *)
        nonneg  : CARDINAL      := 5;                   (* CARDINAL *)
        x       : REAL          := 3.0;                 (* REAL *)
        ch      : CHAR          := 'Q';                 (* CHAR *)
        done    : BOOLEAN       := TRUE;                (* BOOLEAN *)
        str     : TEXT          := "Test";              (* TEXT *)
        arr     : ArrType       := ArrType{0,1,2,3};    (* ARRAY *)
        arr2    : ArrType2      := ArrType2{' ', ..};   (* ARRAY *)
        inFile  : Rd.T;                                 (* Reader *)
        outFile : Wr.T;                                 (* Writer *)
        ltrSet  : SetType := SetType{'a'..'d','z'};     (* SET *)
        head    : Ptr           := NIL                  (* Pointer *)
        st      : Student                               (* RECORD *)
                                := Student{"Joe", 15426, 3.35, NIL};

PROCEDURE One (y: REAL; VAR c: ArrType; x: INTEGER := 5) =
(* Sample procedure definition.  y is a value parameter;
   c is a variable parameter; x is a value parameter with
   a default value *)
VAR i: INTEGER; (* local var *)
BEGIN           (* procedure body *)
  statement-1;
     ... 
  statement-n;
END One;

PROCEDURE Max(a, b: INTEGER): INTEGER =
(* Sample function definition. *)
VAR max: INTEGER;
BEGIN
   max := a;
   IF a < b THEN max := b END;
   RETURN max;
END Max;