Re: OT: and even in Dart .........Re: simple session question

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From	"Peter H. Coffin" <hellsop@ninehells.com>
Newsgroups	comp.lang.php
Subject	Re: OT: and even in Dart .........Re: simple session question
Date	Sat, 5 Nov 2011 15:04:26 -0500
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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

Thread

simple session question cerr <ron.eggler@gmail.com> - 2011-10-21 10:44 -0700
  Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-21 20:19 +0200
    Re: simple session question Jonathan Stein <jstein@image.dk> - 2011-10-21 20:51 +0200
      Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-21 22:00 +0200
        Re: simple session question Jerry Stuckle <jstucklex@attglobal.net> - 2011-10-21 16:14 -0400
          Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-22 00:50 +0200
            Re: simple session question Jerry Stuckle <jstucklex@attglobal.net> - 2011-10-21 19:05 -0400
              Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-22 15:40 +0200
                Re: simple session question Richard Damon <news.x.richarddamon@xoxy.net> - 2011-10-22 17:19 -0400
                Re: simple session question The Natural Philosopher <tnp@invalid.invalid> - 2011-10-22 22:56 +0100
                Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-23 00:35 +0200
                Re: simple session question Tim Streater <timstreater@greenbee.net> - 2011-10-22 23:43 +0100
                Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-23 01:56 +0200
                Re: simple session question Richard Damon <news.x.richarddamon@xoxy.net> - 2011-10-22 19:29 -0400
                Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-23 01:54 +0200
                Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-23 02:12 +0200
                Re: simple session question Richard Damon <news.x.richarddamon@xoxy.net> - 2011-10-22 21:13 -0400
                Re: simple session question The Natural Philosopher <tnp@invalid.invalid> - 2011-10-23 08:44 +0100
                Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-23 17:31 +0200
                Re: simple session question The Natural Philosopher <tnp@invalid.invalid> - 2011-10-23 17:18 +0100
                Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-23 19:14 +0200
                Re: simple session question The Natural Philosopher <tnp@invalid.invalid> - 2011-10-23 18:16 +0100
                Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-23 19:00 +0200
                Re: simple session question Richard Damon <news.x.richarddamon@xoxy.net> - 2011-10-23 15:28 -0400
                Re: simple session question Jerry Stuckle <jstucklex@attglobal.net> - 2011-10-22 23:03 -0400
                Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-23 19:06 +0200
                Re: simple session question Jerry Stuckle <jstucklex@attglobal.net> - 2011-10-23 14:35 -0400
            Re: simple session question The Natural Philosopher <tnp@invalid.invalid> - 2011-10-22 00:32 +0100
              Re: simple session question Luuk <Luuk@invalid.lan> - 2011-10-22 12:01 +0200
                Re: simple session question The Natural Philosopher <tnp@invalid.invalid> - 2011-10-22 15:27 +0100
                Re: simple session question The Natural Philosopher <tnp@invalid.invalid> - 2011-10-22 15:37 +0100
                Re: simple session question Luuk <Luuk@invalid.lan> - 2011-10-22 17:08 +0200
                OT: and even in Dart .........Re: simple session question Luuk <Luuk@invalid.lan> - 2011-10-22 17:17 +0200
                Re: OT: and even in Dart .........Re: simple session question The Natural Philosopher <tnp@invalid.invalid> - 2011-10-22 16:54 +0100
                Re: OT: and even in Dart .........Re: simple session question Luuk <Luuk@invalid.lan> - 2011-10-22 18:47 +0200
                Re: OT: and even in Dart .........Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-22 19:34 +0200
                Re: OT: and even in Dart .........Re: simple session question Norman Peelman <npeelmandog@cfl.rr.com> - 2011-10-22 16:08 -0400
                Re: OT: and even in Dart .........Re: simple session question Jerry Stuckle <jstucklex@attglobal.net> - 2011-10-22 16:28 -0400
                Re: OT: and even in Dart .........Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-23 01:39 +0200
                Re: OT: and even in Dart .........Re: simple session question Norman Peelman <npeelmandog@cfl.rr.com> - 2011-10-22 22:40 -0400
                Re: OT: and even in Dart .........Re: simple session question Jerry Stuckle <jstucklex@attglobal.net> - 2011-10-22 23:05 -0400
                Re: OT: and even in Dart .........Re: simple session question The Natural Philosopher <tnp@invalid.invalid> - 2011-10-22 22:52 +0100
                Re: OT: and even in Dart .........Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-23 01:25 +0200
                Re: OT: and even in Dart .........Re: simple session question The Natural Philosopher <tnp@invalid.invalid> - 2011-10-23 08:41 +0100
                Re: OT: and even in Dart .........Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-23 00:56 +0200
                Re: OT: and even in Dart .........Re: simple session question Norman Peelman <npeelmandog@cfl.rr.com> - 2011-10-22 22:52 -0400
                Re: OT: and even in Dart .........Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-23 17:12 +0200
                Re: OT: and even in Dart .........Re: simple session question Tim Streater <timstreater@greenbee.net> - 2011-10-23 09:39 +0100
                Re: OT: and even in Dart .........Re: simple session question The Natural Philosopher <tnp@invalid.invalid> - 2011-10-23 09:40 +0100
                Re: OT: and even in Dart .........Re: simple session question Tim Streater <timstreater@greenbee.net> - 2011-10-23 09:43 +0100
                Re: OT: and even in Dart .........Re: simple session question "Peter H. Coffin" <hellsop@ninehells.com> - 2011-11-05 15:04 -0500
                Re: OT: and even in Dart .........Re: simple session question The Natural Philosopher <tnp@invalid.invalid> - 2011-10-22 22:47 +0100
                Re: OT: and even in Dart .........Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-23 01:22 +0200
                Re: OT: and even in Dart .........Re: simple session question The Natural Philosopher <tnp@invalid.invalid> - 2011-10-23 08:40 +0100
                Re: OT: and even in Dart .........Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-23 17:04 +0200
                Re: OT: and even in Dart .........Re: simple session question "Peter H. Coffin" <hellsop@ninehells.com> - 2011-11-05 15:00 -0500
              Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-22 15:39 +0200
    Re: simple session question cerr <ron.eggler@gmail.com> - 2011-10-21 14:43 -0700
      Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-22 00:47 +0200
      Re: simple session question Jerry Stuckle <jstucklex@attglobal.net> - 2011-10-21 19:06 -0400
    Re: simple session question cerr <ron.eggler@gmail.com> - 2011-10-21 14:17 -0700
      Re: simple session question Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2011-10-22 15:50 +0200
    Re: simple session question Denis McMahon <denismfmcmahon@gmail.com> - 2011-10-23 15:47 +0000

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