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Date: Sat, 21 Dec 2013 11:29:00 +0100
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Subject: RE: [PHP-DEV] Re: power operator (again)
From: php@tutteli.ch ("Robert Stoll")

> -----Original Message-----
> From: Rowan Collins [mailto:rowan.collins@gmail.com]
> Sent: Friday, December 20, 2013 10:28 AM
> To: internals@lists.php.net
> Subject: Re: [PHP-DEV] Re: power operator (again)
> 
> Kris Craig wrote (on 20/12/2013):
> > But now, let's look at another scenario:
> >
> > <?php
> >
> > $x = -3;  // Or $x = -1 * 3, if you wish.
> >
> > $y = $x ** 2;
> >
> > ?>
> >
> > What would be the value of $y under this RFC?
> 
> That has nothing to do with operator associativity: $x has already been
> calculated as -3, just as if it were $y = (-3) ** 2
> 

That's actually wrong. Consider the following code snippet:

echo ( -3 * 2); // -6
$x = -3;
echo $x * 2; // -6 -> does not behave like (-3) * 2
$x = "-3";
echo $x * 2; // -6 -> does not behave like (-3) * 2

But I think it would be more intuitive if it would behave as (-3) 

> Consider the same thing with mixed addition and multiplication:
> 
> $y = 1 + 2 * 3;
> // $y is 7, due to operator precedence
> 
> $y = (1 + 2) * 3;
> // $y is 9, due to the brackets
> 
> $x = 1 + 2;
> $y = $x * 3;
> // $x is 3, so $y is 9; operator precedence is irrelevant
> 
Nope, that's not true. 1+2 is just already evaluated and the result was stored in $x rather than the expression. 

> As I said before, I think people don't always think of "-3" as an
> operator applied to a literal, but by the same token, they are rather
> unlikely to write something like "-$x". That limits this whole debate on
> associativity to those cases where somebody hard-codes a negative value
> like -3, and doesn't think to add parentheses.
> 
> Regards,
> --
> Rowan Collins
> [IMSoP]
> 
> --
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