On 30.07.21 02:01, Кирилл Несмеянов wrote:
Yes, I saw this short description in your RFC (
https://wiki.php.net/rfc/enumerations ) about «enum sets». However, I do not
quite understand why we can not now add a cast to scalars (string and int) and
math expressions, which would solve this problem? This behavior has already
been implemented for GMP objects.
$mask = gmp_init(0b0001) | gmp_init(0b0010); // object(GMP) { num = 3; }
echo $mask; // 3
$mask = $mask + 1; // object(GMP) { num = 4; }
$mask instanceof \GMP; // true
I mean, for such cases, we can create a new "virtual enum case" containing a new value instead special «EnumSetCase».
enum Some: int
{
case A = 0b0001;
case B = 0b0010;
}
var_dump(Some::A | Some::B); // enum(Some::@anonymous) { value = 3; }
I don’t think that it is necessary to consider the «enum sets» as a separate case, cause addition is also a fairly popular case:
case LAST = self::B + 1;
Like any other mathematical operations.
I think you missing something
Consider this example:
enum Some: int
{
case A = 0b0001;
case B = 0b0010;
case C = 0b0011;
}
var_dump(Some::B | Some::C)
This should result in a set of B|C but with your logic it's the same as
just C.
and it also needs to work with strings:
enum Some: string
{
case A = 'a';
case B = 'b';
case C = 'c';
}
This is where enum sets comes into play.
Without having PHP internals C knowledge I think it should be possible
to introduce an EnumSet which internally handles a bit array where each
bit is pointing to the position (ordinal) of an enum case but I don't
think the ordinal position is guarantied to be stable over
processes/versions so this would not directly by serializable nor do we
have generics to define an enum set of a specific type (ala EnumSet<Some>).
Marc
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