PLI Boolean Operators – Real Purpose

Boolean Operators

Boolean operators are 1 bit in PLI language. You can use for conditional logic very often in PLI language.

In PL/I Bit(1) strings represents single Boolean values

• '1'B is interpreted as True
• '0'B is interpreted as False

Bit(1) strings may be used as boolean expressions in conditional and loop statements.

declare   my_bit   bit (1);
   my_bit = ( 1 < 2 );   /* now my_bit has the value '1'B */
   my_bit = ( 2 < 1 );   /* now my_bit has the value '0'B */
   .....
   if my_bit then
      put skip list ( 'value of my_bit is true' );
   else
      put skip list ( 'value of my_bit is false' );
   do while ( my_bit );
      .....
   end;

Boolean operators may be used for calculating new values

• The prefix operator ¬ is used as logical NOT.
• The infix operator & is used as logical AND.
• The infix operator | is used as logical OR.

How to declare Boolean values 

declare   bit_a    bit (1);
declare   bit_b    bit (1);
declare   result   bit (1);
result = ¬ bit_a;  
/* result = '1'B if and only if bit_a is '0'B */
result =   bit_a & bit_b;   
/* result = '1'B if and only if both bit_a and bit_b are '1'B */
result =   bit_a | bit_b;   
/* result = '0'B if and only if both bit_a and bit_b are '0'B */

Note: Using compile-time options NOT operator and OR operator may be replaced by other symbols, for being compatible with existing PL/I programs often ^ is used as NOT, ! is used as OR.