PRED                  Return the Predecessor of Number               pp 141

 Syntax:  Pred (Scalar) ;

 Type:    Data type                   

 Form:    Function, procedure, declaration

 Purpose: Returns the preceeding value of an ordinal type.

 Notes:   Pred of the first value of an ordinal type is undefined.
          {$R-} strict range checking is off (default) then Pred will
          wrap around to zero minus one.  Type Byte wraps to 255 and type
          Integer wraps to -1 ($FFFE).


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 Usage:
       TYPE
          Rainbo = (Red,Orange,Yellow,Green,Blue,Indigo,Violet) ;

       CONST
          Index  : Byte = 4 ;
          Colors : Array [0..6] of String [3] =
                   ('Red','Org','Yel','Grn','Blu','Ind','Vio');

       VAR
          Bands  : Rainbo                 ;  { Bands is type Rainbo        }
          ChrVar : Char                   ;  { Character variable          }
          BytVar : Byte                   ;  { Byte variable               }
          IntVar : Integer                ;  { Integer variable            }
          StrVar : String [3]             ;  { String variable             }


       BEGIN
          BytVar := Pred (0)              ;  { BytVar = 255                }
          IntVar := Pred (0)              ;  { IntVar = -1 or $FFFE        }
          ChrVar := Pred ('Z')            ;  { ChrVar = Y                  }
          Index  := Pred (Ord(Yellow))    ;  { Set index to 1              }
          Bands  := Pred (Orange)         ;  { Bands = Red                 }
          {$R+}                           ;  { Strict range checking on    }
          Bands  := Pred (Red)            ;  { Undefined, gives R/T Err 91 }
          StrVar := Colors [Pred (Index)] ;  { Red                         }
       END.