Re: [Proposal] Modification to ?: functionality

On Tue, Nov 26, 2013 at 12:41 PM, Paul Dragoonis <dragoonis@gmail.com> wrote: > On Tue, Nov 26, 2013 at 4:58 PM, Chris London <me@chrislondon.co> wrote: > >> On Tue, Nov 26, 2013 at 8:15 AM, Mats Lindh <mats.lindh@gmail.com> wrote: >> >> > On Tue, Nov 26, 2013 at 3:43 PM, Chris London <me@chrislondon.co> wrote: >> > >> >> I believe these two statements are functionally equivalent: >> >> >> >> $foo = $foo ? $foo : 'default'; >> >> >> >> $foo = $foo ?: 'default'; >> >> >> > >> > They are. >> > >> > >> > I would like to change it so it also checks for isset() so I propose the >> >> following would be functionally equivalent: >> >> >> >> $foo = isset($foo) && $foo ? $foo : 'default'; >> >> >> >> $foo = $foo ?: 'default'; >> >> >> > > We can't change the behaviour of ?: that ship has already sailed, we'll > just be hurting existing codebases on upgrading and more user education is > required to understand non-visual changes in syntax like this, lets try to > learn from our mistakes by not changing 'behaviour' anymore. > > An alternative syntax that is similar and not ugly would be good since the > ?: behaviour was broken from the start since you still need to run isset() > before running ?: which was the problem we tried to solve in the first > place but it just didn't happen. > > I don't like the @ symbol it's too different from what's already there on > the ternary logic. > > Proposal: $foo = $arr['value'] ?:: ""; > > Thoughts? > >> >> > The would break the assumption that a reference to an uninitialized value >> > would generate a notice, unless explicitly handled in the logic. >> > >> > While I also would like to have something similar to ?: to handle default >> > values for array keys, etc., this would change a fundamental assumption >> > that as been in place for many years now. I'm not sure if that's a BC >> break >> > that would be acceptable this late. An alternative operator may be more >> > suitable. >> > >> >> What do you think about using: >> >> $foo = $foo @: 'default'; >> >> and possibly >> >> $foo @= 'default'; >> >> >> >> > >> > The change proposed has also been discussed several times since the >> > implementation of ?:. See the ifsetor-RFC: >> > >> > https://wiki.php.net/rfc/ifsetor >> > >> > It also contains links to the discussion around the feature back then. >> > >> > --mats >> > >> This seems like a cracking time to suggest: $x ||= $y; The difference? Anything left of the ? SHOULD fail if it is not set, because you are using it in a condition which is dangerous and odd for other types of condition, but adding in this new syntax (similar to Ruby) would essentially evaluate to this: empty($x) ? $y : $x; This gives keeps the behavior of ternary operators working in the same way, but adds what we want: the ability to nicely set defaults for variables and array keys that may not be set.