$handle = fopen('test.csv', 'r');
while (($data = fgetcsv($handle)) !== false) {
[int $id, string $data, int $year] = $data;
// do something with the correctly typed variables
}
The code would trigger a fatal error when strict_types are enabled. With
strict_types disabled it would behave identically as the currently
proposed casts.
As I mentioned in a previous e-mail, if it followed current strict_types=0
semantics, it would error if the input row was something like
"42,hello,not-a-valid-year".
Following standard cast semantics, that input would instead silently give
you a value of 0 in $year, which is often not what you want.
Hi Rowan,
I liked your idea of strict casts which would increase the possibilities
of casting in general but also improve casting while array destructuring.
Let's have a look at various combinations.
The current proposal (behaviour doesn't depend on strict_types):
[(int) $id, (string) $data, (int) $year] = $data;
"42,hello,2020" --> Works as expected, everything fine
"42,hello,not-a-valid-year" --> results silently in a 0. May not be
wanted, as you describe, but in my opinion that's fine as it's the
current casting behaviour
Extending the proposal with strict castings (behaviour doesn't depend on
strict_types):
[(!int) $id, (!string) $data, (!int) $year] = $data;
"42,hello,2020" --> Works as expected, everything fine as "2020" can be
casted to an int
"42,hello,not-a-valid-year" --> Results in a TypeError as the year can't
be casted to an int
Using regular type checks (depends on strict_typed):
declare(strict_types=0);
[int $id, string $data, int $year] = $data;
"42,hello,2020" --> Works as expected, everything fine as the id with
"42" and the year with "2020" can be casted to an int
"42,hello,not-a-valid-year" --> Results in a TypeError as the year can't
be casted to an int
declare(strict_types=1);
[int $id, string $data, int $year] = $data;
"42,hello,2020" --> Results in a TypeError as id and year are both strings
"42,hello,not-a-valid-year" --> Results in a TypeError as id and year
are both strings
My favourite behaviour would be the one described for strict
castings/regular type checks with strict_types disabled. But I don't
like the idea it's only usable without strict_types to get the
casting-feature intended by the RFC.
Cheers, Enno