Re: [RFC] Using objects as keys

> On Oct 30, 2014, at 1:32 PM, Stas Malyshev <smalyshev@sugarcrm.com> wrote: > > Hi! > >> Put another way, I think a key question here is: >> >> class Foo { >> public $bar; >> } >> >> $a = new Foo; >> $a->bar = 'baz'; >> $b = new Foo; >> $b->bar = 'baz'; >> >> $arr[$a] = true; >> $arr[$b] = true; >> >> >> Does $arr now contain one value or two? > > That depends on the semantics of class Foo. If Foo is something like > UString, then it should contain one value, since UString is a value > object (https://en.wikipedia.org/wiki/Value_object) - or at least it > should be. However, if Foo represents something having separate identity > - i.e. it's a Person class and 'bar' represents name - then of course it > should contain two values, since the name is not the sole source of > Person's identity. So the decision is on you as a programmer. > > And to give you the tool to make this decision and let PHP engine know > about is exactly the point of this RFC. My only concern at this point is the default value of the hash. If we were to use spl _object_hash, we could be setting a precedence that a hash must be unique to each object. Any thoughts on that? > >> If the desire is for it to contain 2, then spl_object_hash($a) already >> has that covered, I think. >> >> If the desire is for it to contain 1, then the proposal sounds like a >> way to normalize Foo::stringifiedValueObjectEquivalent(). > > You can describe it as such, but in a proper standartized way and with > syntax that allows you to use same syntax constructs on all keys and not > have to check each time if it's a special value and call a special > function on it (same purpose as for __toString). > -- > Stanislav Malyshev, Software Architect > SugarCRM: http://www.sugarcrm.com/ > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php >