I think what Jose is trying to say, is that because 'or' has a lower
precidence than =, you are interpreting the expression wrong.
$b1 = is_null($x) or ($y > 5);
is the same as
($b1 = is_null($x)) or ($y > 5)
This assigns the value of is_null($x) to $b1, regardless of the result
of ($y > 5). It's shorthand for
if( !($b1 = is_null($x)) ){
($y > 5);
}
similarly
$b2 = ($y > 5) or is_null($x);
assigns $b2 to ($y > 5), or in this case true(since $y == 10). If ($y
> 5) returned false, ie if $i <= 5, then it would call the function
is_null($x). In this case calling the function is_null() is pointless,
since you aren't using the result.
What I think you are looking for is either
$b2 = (($y > 5) or is_null($x)); // whole thing right of = enclosed in brackets
or
$b2 = ($y > 5) || is_null($x); // '||' has higher precidence than 'or'
On Fri, 24 Dec 2004 16:47:42 -0300, Jose M.Herrera
<jherrera@xxxxxxxxxxxx> wrote:
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> Hash: SHA1
>
> Bogdan Ribic wrote:
> | Here's a little test script:
> |
> | --------------------
> | $x = 2;
> | $y = 10;
> |
> | $b1 = is_null($x) or ($y > 5);
> | $b2 = ($y > 5) or is_null($x);
>
> Yes, of course.
> Your code or example, is just like:
>
> ( $b1 = is_null($x) ) or ( $y > 5 ) ;
> ( $b2 = ($y > 5) ) or is_null($x) ;
>
> The ">" has more precedence than "=", "or" it has a very low precedence.
> Then, $b1 = false and $b2 = True... that's ok! :P
>
> You example, must have been:
>
> $b1 = ( ( is_null($x) ) or ( $y > 5 ) );
> $b2 = ( ( $y > 5 ) or ( is_null($x) ) );
>
> I this example the value of $b1 is all between the parenthesis (explicitly).
>
> Bye!
>
> - --
> Jose Miguel Herrera M. - User #246070 counter.li.org
> Est.Ing.Civil Informatica - UTFSM
> Valparaiso, Chile - http://www.inf.utfsm.cl/~jherrera
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