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Postings from December 2021
On 2021-12-19 2:53 a.m., Martijn Lievaart wrote:
> Op 19-12-2021 om 11:48 schreef Darren Duncan:
>> Well the other reasonable solution is to treat the pair as "if the expression
>> result is true" and "if the expression result is anything else". I actually
>> thought of proposing that and then I didn't.
>>
>> However, doing that means these 2 things will behave differently in the
>> presence of unknown where they wouldn't otherwise:
>>
>> if ($x) {
>> foo();
>> }
>> else {
>> bar();
>> }
>>
>> if ($x) {
>> foo();
>> }
>> if (!$x) {
>> bar();
>> }
>>
> I like it from a conceptual point of view. It feels right. It feels correct. But
> only for new code that is written with this 3VL in mind. Otherwise I think it
> will open a can of bugs in existing code, so that probably should still die.
I still think, however, my original proposal of neither if nor else running when
an unknown is input, is probably more correct and consistent with the wider context.
That interpretation means both of the above examples behave the same as each
other, same as would be the case under 2VL.
A stronger supporting point is that the do-nothing answer is more consistent
with the examples Ovid gave about desired behavior for "grep" or such, which is
that unknown are omitted from the result no matter whether the grep condition
tests for truthiness or falseiness, which is also the same as how SQL WHERE
behaves with NULL.
-- Darren Duncan
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