Boolean Values

true and false are used for true and false, respectively. However, any value may be converted to a boolean using the $istrue function, which returns false for false, null, and 0, and true for anything else. The $not function does just the opposite. For if and while expressions, only true will be considered true.

Boolean Operations

&& is logical “and” and || is logical “or”. These operations are short-circuited and do not convert the values to booleans.

For example:

$print(false || "Hello"); //prints "Hello"