I would prefer:
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($amount).' given');
}
}
Regards
Thomas
Sven Drieling wrote on 03.02.2015 20:07:
> Am Mon, 02 Feb 2015 23:38:21 +0100
> schrieb Christoph Becker <cmbecke...@gmx.de>:
>
> Hallo,
>
>> >> addVat(-1);
>>
>> Well, my point was that even a strict type system doesn't necessarilly
>> catch all erroneous/undesired arguments. Even if addVat() properly
>> handles negative numbers, and maybe even zeroes, there are functions
>> that can't.
>
> What about scalar type declaration in userland?
>
>
> namespace mytypes;
>
>
> declare scalartype amount($amount) {
> if (!is_int($amount) && !is_float($amount)) {
> throw new InvalidArgumentException('Argument amount
> must be of the type int|float, '.gettype($amount).' given');
> }
> }
>
>
> function addVat(mytypes\amount $amount) {
> return round($amount*1.19, 2);
> }
>
> addVat(42) // OK
> addVat("42") // OK
> addVat(-42) // OK
> addVat(42.0) // OK
> addVat(true) // Exception
>
>
> var mytypes\amount $amount = 0;
>
> $amount = 42; // OK
> $amount = "42"; // OK
> $amount = true; // Exception
>
>
>
> tschuess
> [|8:)
>
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