FUDforum
Fast Uncompromising Discussions. FUDforum will get your users talking.
Home » Imported messages » comp.lang.php » simple session question
Show: Today's Messages :: Polls :: Message Navigator
Return to the default flat view Create a new topic Submit Reply
Re: OT: and even in Dart .........Re: simple session question [message #175910 is a reply to message #175724] Sat, 05 November 2011 20:04 Go to previous messageGo to previous message
Peter H. Coffin is currently offline  Peter H. Coffin
Messages: 245
Registered: September 2010
Karma:
Senior Member
On Sat, 22 Oct 2011 16:08:01 -0400, Norman Peelman wrote:
> On 10/22/2011 01:34 PM, Thomas Mlynarczyk wrote:
>> Luuk schrieb:
>>> i did send a bug-report:
>>> https://bugs.php.net/bug.php?id=60114
>>
>> I do not see any bug here. I was confused because it's a crappy way to
>> code, but it's clear why it works the way it does:
>>
>> $foo = 0;
>> $foo = $foo++;
>>
>> is definitely identical to
>>
>> $foo = 0;
>> $foo = ($foo++);
>>
>> since ++ has higher precedence than =. In fact, ($foo = $foo)++ does
>> rightfully throw a parse error, since you can only increment a variable,
>> not an expression.
>>
>> As mentioned before in this thread, the above code is equivalent to
>>
>> $foo = 0;
>> $tmp = $foo; // $foo++ yields the previous value, which is 0
>> $foo = $foo + 1; // then $foo is incremented...
>> $foo = $tmp; // ...and then re-assigned the old value
>>
>> It's the exact same procedure as it would be with $foo = $bar++.
>>
>> Greetings,
>> Thomas
>>
>
> No they are not the same.
>
> $foo = 0;
> $foo = $foo++;
>
> It should be equivalent to:
>
> $foo = 0; // 0
> $foo = $foo; // 0 = 0
> $foo = $foo + 1; // 0 = (0 + 1)
>
> $foo++ means that the variable is to be incremented after the variable
> is accessed. Something is clobbering that increment.

Yes. The ASSIGNMENT back to $foo is clobbering it. The increment happens
immediately after access, before the VALUE is passed back to the
assignment.

> ++$foo means that the variable is to be incremented piror to the
> variable being accessed. Works as expected.
>
>
> Haven't seen the source code but there must be some temporary
> variable that's getting clobbered for the $foo++ example.

It's just happening in the proper order. increment happens before
assignment, exactly per
http://php.net/manual/en/language.operators.precedence.php

The catch is that the assignment is destroying the increment, because
the variable access happened BEFORE the increment.

--
17. When I employ people as advisors, I will occasionally listen to
their advice.
--Peter Anspach's list of things to do as an Evil Overlord

Report message to a moderator

[Message index]
 
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Previous Topic: session cookie: client side
Next Topic: by get this format my explode file name like this through php
Goto Forum:
  

-=] Back to Top [=-
[ Syndicate this forum (XML) ] [ RSS ]

Current Time: Thu Nov 28 14:52:53 GMT 2024

Total time taken to generate the page: 0.04577 seconds
.:: Contact :: Home ::.

Powered by: FUDforum 3.1.3.
Copyright ©2001-2023 FUDforum Bulletin Board Software