The function Michael Smith published doesn't do the work as it should.
To check if a variable is boolean is one thing, to evaluate if the value of a variable represents a boolean condition (true or false) is another.
Here a simple function that checks the status of the received variable in regards to boolean equivalencies (case insensitive).
<?php
/**
* Check "Booleanic" Conditions :)
*
* @param [mixed] $variable Can be anything (string, bol, integer, etc.)
* @return [boolean] Returns TRUE for "1", "true", "on" and "yes"
* Returns FALSE for "0", "false", "off" and "no"
* Returns NULL otherwise.
*/
function is_enabled($variable)
{
if (!isset($variable)) return null;
return filter_var($variable, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE);
}
?>
Of course, it is a simplistic approach, but for the majority of cases it will do the job right.
And, just to put thing in the right perspective, here's a real function that does what Phill disclosed:
<?php
/**
* Convert $variable to boolean (adapted from Phill answer)
*
* @param [mixed] $variable Can be anything
* @return [boolean] Returns the booelan equivalent to $variable based on Zend Enegine interpretation
*/
function to_bool($variable)
{
return (bool)$variable;
}
?>
I hope it helps someone. Happy coding.