/**
* Strings always evaluate to boolean true unless they have a
* value that's considered "empty" by PHP (taken from the
* documentation for empty):
* "" (an empty string) evaluates as false.
* "0" (0 as a string) evaulates as false.
* If you need to set a boolean based on the text value of a
* string, then you'll need to check for the presence or
* otherwise of that value.
*/
$boolean = $string === 'true' ? true: false;