Hi all,
On Wed, Feb 4, 2015 at 5:23 AM, Thomas Bley <ma...@thomasbley.de> wrote:
> function addVat($amount) {
> validateAmount($amount);
> return round($amount*1.19, 2);
> }
>
> function validateAmount($amount) {
> if (!is_int($amount) && !is_float($amount)) {
> throw new InvalidArgumentException('Argument amount must be of the
> type int|float, '.gettype($amount).' given');
> }
> }
>
I use such code where runtime check is required.
I prefer following for better performance/readability. i.e. Pre/Post
conditions are inside of function definition.
If PHP supports native DbC, runtime checks are omitted and script runs
faster. NOTE: Dev time checks are
done in in/out block with proper DbC design. Runtime check should be in
function body.
function addVat($amount)
in {
// precondition check
assert(!is_int($amount) && !is_float($amount));
// OR
if (!is_int($amount) && !is_float($amount)) {
throw new InvalidArgumentException('Argument amount must be of the type
int|float, '.gettype($amount).' given');
}
}
out {
// postcondition check
assert(is_numeric($__return_vlaue) && $__return_value > 0 &&
$__return_value < MAX_AMOUNT);
}
{
// function body
return round($amount*1.19, 2);
}
Type hints are useful for simple runtime check.
Much less lines to write ;) It also encourage users to validate their app
inputs. This is important benefits for secure apps.
Things like these encourage proper DbC design naturally. Therefore, I'm +1
for all of these.
Regards,
--
Yasuo Ohgaki
yohg...@ohgaki.net
