> -----Original Message-----
> From: Miguel Cruz [mailto:[EMAIL PROTECTED]]
> Sent: 29 April 2002 05:34
>
> On Sun, 28 Apr 2002, Richard Emery wrote:
> > The answer is:
> > $file_pointer = fopen('/public_html/emails.txt', "a") or exit;
> >
> > The " || " is a binary operation. You want "or", the
> logical operation.
>
> Yeah, Perl habit.
>
> But || is logical too (it's | that's binary), it just seems
> to result in
> $file_pointer being recast from 'resource' to 'boolean' for
> some reason.
>
> This side effect is not mentioned at
> http://www.php.net/manual/en/language.operators.logical.php where it
> imples that the only difference is precedence. I'd say this is a bug
> either in the manual or in PHP itself.
Surely this is *precisely* due to the difference in precedence. The or operator has
lower precedence than =, whereas || has higher precedence, so:
$file_pointer = fopen(...) or exit;
would be ($file_pointer = fopen(...)) or exit;
(i.e. evaluate the assignment expression first, and if it returns a false value then
exit)
whereas
$file_pointer = fopen(...) || exit;
would be $file_pointer = (fopen(...) || exit);
(i.e. evaluate the Boolean or first, casting the fopen() result in the process, then
assign the result to $file_pointer (assuming exit hasn't already terminated execution
by then!)).
So, no bug, no unexpected side-effects, just a logical result of applying the
precedence rules strictly as advertised!
Cheers!
Mike
---------------------------------------------------------------------
Mike Ford, Electronic Information Services Adviser,
Learning Support Services, Learning & Information Services,
JG125, James Graham Building, Leeds Metropolitan University,
Beckett Park, LEEDS, LS6 3QS, United Kingdom
Email: [EMAIL PROTECTED]
Tel: +44 113 283 2600 extn 4730 Fax: +44 113 283 3211
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