Boolean values: Difference between revisions

=={{header|PL/M}}==

In PL/M, even numbers are falsy and odd numbers are truthy. That is to say, conditional expressions test only the low bit of the value.

<lang pli>IF 0 THEN /* THIS WON'T RUN */;

IF 1 THEN /* THIS WILL */;

IF 2 THEN /* THIS WON'T */;

IF 3 THEN /* THIS WILL */;</lang>

Canonically, false is represented by <code>0</code> (all bits clear), and true by <code>0FFH</code> (all bits set). These are the values that conditional operators (like <code>=</code>) return.

<lang pli>DECLARE A BYTE;

A = 4 < 5;

/* A IS NOW 0FFH */</lang>

Boolean literals are not included by default, but it is not uncommon for programmers to define them by hand:

<lang pli>DECLARE FALSE LITERALLY '0', TRUE LITERALLY '0FFH';</lang>