On Thu, Jun 27, 2024, at 23:46, Jordan LeDoux wrote:
>
>
> On Thu, Jun 27, 2024 at 2:35 PM Rob Landers <rob@bottled.codes> wrote:
>> __
>>
>>
>> On Thu, Jun 27, 2024, at 06:07, Saki Takamachi wrote:
>>>
>>> I agree with Gina. Being able to change the class of a computed result of
>>> an inherited child class causes several problems.
>>>
>>> The points raised in the `BCMath\Number` discussion can be summarized as
>>> follows.
>>>
>>> - If it is possible to perform calculations on parent Class and child
>>> Class, what should the resulting class be?
>>
>> Ask the class what it wants to be?
>>
>>> - Multiplying the distance class and the speed class should give you the
>>> time class.
>>
>> That would depend on the library’s implementation.
>>
>>> - Similarly, multiplying two distance classes together should yield an area
>>> class.
>>
>> See above.
>>
>>> - If only child classes have a property that should be specified in the
>>> constructor, how do you determine the value of this property in the result
>>> class? Perhaps it is possible to determine the value of the property, but
>>> in that case the commutativity of the computation should be lost.
>>
>> This can be handled via the child class in static methods, per the library
>> specifications.
>
> How is the library supposed to do that in the absence of operator handler
> functions that can be overridden, or at least called when an operator is
> encountered?
>
> Jordan
That’s what this email is about: adding those functions to the base GMP class
as static protected methods.
A time class would look something like:
static protected add(GMP $left, GMP $right) {
if($left instanceof self && $right instanceof self) return new
self(parent::add($left, $right));
throw new LogicException('can only add time to time');
}
— Rob
