NYCPHP Meetup

[Michael B Allen]

On Tue, Sep 9, 2008 at 10:56 PM, Hans Zaunere <lists at zaunere.com> wrote:
>> Nevermind - $key is an int so 'foo' is being cast to an int which
>> evaluates to 0.
>>
>> I think I would prefer that switch be a little more explicit.
>>
>> >        switch ($key) {
>> >                case 'foo':
>> >                case 'bar':
>> >                        echo "[$key][$val]\n";
>> >                        break;
>> >        }
>> > }
>> >
>> > $ php -f switch.php
>> > [foo][1]
>> > [bar][2]
>> > [0][zap]
>
> Should switch be more explicit, or should the programmer? :)  Don't depend
> on auto type casting...

That's what I'm saying.

In this case PHP looks at $key and sees (int)0. So now it auto type
casts 'foo' to an int which for any string yields (int)0 and thus the
case matches the 0 => 'zap' element unexpectedly. If switch used a
typed comparison it would not auto type cast and it would compare
(int)0 to (string)'foo' and because the types do not match I would get
the expected results.

But of course if switch used a typed comparison you would have to code
something like:

  $str = '5';
  switch ($str) {
      case 5:
          // no match ?!
          break;
      case 'foo':
          ...

as:

  $str = '5';
  switch ($str) {
      case 5:
      case '5':
          // ahhh, now it matches
          break;
      case 'foo':
          ...

with double cases which people would no doubt be hee'n and haw'n over to no end.

M

-- 
Michael B Allen
PHP Active Directory SPNEGO SSO
http://www.ioplex.com/