Re: [Proposal] Modification to ?: functionality

On Tue, Nov 26, 2013 at 6:57 PM, Philip Sturgeon <pjsturgeon@gmail.com>wrote: > 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. > To me this reads as $x = $x || $y like all the <OP>= binary operators. So it would definitely feel weird to use that syntax for something else... > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php > > -- Etienne Kneuss http://www.colder.ch