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Date: Thu, 23 Jun 2011 12:13:07 -0300
Message-ID: <BANLkTi=aE4EhJ=JgSP3bw1hwvftUHQk_pQ@mail.gmail.com>
To: Ferenc Kovacs <tyra3l@gmail.com>
Cc: Stefan Neufeind <neufeind@php.net>, internals@lists.php.net
Content-Type: multipart/alternative; boundary=bcaec53af1dcbbfeab04a66285c0
Subject: Re: [PHP-DEV] Variable scopes for language constructs (foreach, ...)
From: martinscotta@gmail.com (Martin Scotta)

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Content-Type: text/plain; charset=ISO-8859-1

 Martin Scotta


On Thu, Jun 23, 2011 at 12:09 PM, Ferenc Kovacs <tyra3l@gmail.com> wrote:

> On Thu, Jun 23, 2011 at 5:03 PM, Stefan Neufeind <neufeind@php.net> wrote:
>
> > Hi,
> >
> > I've lately discussed with a colleague which scopes of variables exist
> > for PHP or would probably make sense. In general I think the general
> > idea of having variables available all throughout a function is okay as
> > this allows things like
> >
> > foreach($vals as $v) {
> >  // ...
> >  $found = true;
> > }
> > if($found) {
> >  // ...
> > }
> >
> > (setting $found inside the loop while still being able to access it
> > outside)
> >
> > But the interesting part is that $v is also still available outside the
> > loop (last value). While most people would say this is not a big
> > problem, it can become problematic when using references.
> >
> > foreach($vals as &$temp) {
> >  // ...
> > }
> > // ...
> > $temp = 5;
> > (when you don't think about the reference anymore but want some
> > temp-variable)
> >
> >
> > If this has been "throughly discussed" before, please excuse. But if not
> > maybe somebody could share his oppinion on the following proposal.
> >
> > What if we (for example with PHP 5.4 or if not possible maybe with the
> > next one) change the behaviour so that
> >
> > * variables used for key/value in foreach (probably other places?) would
> > be limited to that loop-scope
> >
> > and maybe
> > * variable $found in the first example would need to be initialised
> > before the loop. Otherwise it would be a new variable inside the scope
> > of foreach that would be gone afterwards
> >
> > and/or maybe
> > * allowing to explicitly limit variable-scopes inside blocks, for
> > example by allowing    var $found   somewhere inside a function to allow
> > things like
> >
> > if($a) {
> >  var $temp;
> >
> >  $temp = 5;
> > }
> > // and $temp would be gone here; was limited to the scope in which it
> > was defined by var
> >
> >
> > Hope this is not too much of a non-sense idea to you :-)
> >
> >
> Hi,
>
> it was discussed many times on the list, and this behavior is also
> documented, see
> http://php.net/manual/en/control-structures.foreach.php
>
> "Reference of a $value and the last array element remain even after the
> foreach loop. It is recommended to destroy it by unset()."
>
> personally I find that weird, and unintuitive, but changin that in a major
> or minor version could be changed if we chose to.
>
>
What if the unset is injected at core level ?




> Tyrael
>

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