On 12/05/2016 12:36, Lester Caine wrote:
On 12/05/16 11:21, Davey Shafik wrote:
E.g. the behavior of passing executing with a null value for the
argument is something you should be consciously making a decision on,
and passing in null explicitly.
I was actually getting the logic wrong... the problem with this proposal
is that I HAVE to add the '?' for many of my libraries to continue to
work simply because they do handle the null case. So what was a working
system is broken by this change.
As I understand it, no existing code will change behaviour under this
proposal. It merely adds an extra feature which libraries *can* use.
What's more, it's a feature which makes those libraries *less strict*,
not more.
Existing code:
function something(Bar $bar) {}
something(new Bar); // OK
something(); // Error: Missing required parameter
something(null); // Error: Parameter is not of required type
function something_else(Bar $bar = null) {}
something_else(new Bar); // OK
something_else(); // OK
something_else(null); // OK
None of this behaviour is going to change, no existing code will break.
Now let's say the author of the something function decides to use the
new nullable type hint:
function something(?Bar $bar) {}
something(new Bar); // OK
something(); // Error: Missing required parameter
something(null); // OK
None of your code will be calling something(null) yet, because it was
previously an error. So you now have an *extra* way of calling the
function, but you don't need to change any existing usages.
The only breaking change would be if the author of the something_else
function decided to make the argument mandatory but nullable, so that
"something_else()" would be an error, but "something_else(null)"
wouldn't be. But that's just the same as if they made the argument
completely mandatory - it's a breaking change in the library, not
something the language change has caused to happen.
Regards,
--
Rowan Collins
[IMSoP]
--
PHP Internals - PHP Runtime Development Mailing List
To unsubscribe, visit: http://www.php.net/unsub.php
