eval problem

[iulian.ilea]

Hi,
I have to eval a string stored in a variable, but it's not working.
code:
___

function ee($s)
{
return $s;
}

$v="e(\"name\") ";

eval("$stri=$v; ");
echo $stri;
___

By using eval I want to eval $v and get the result returned by ee
stored in $stri. How woul you do?

[Janwillem Borleffs]

Re: eval problem

iulian.ilea wrote:

By using eval I want to eval $v and get the result returned by ee
stored in $stri. How woul you do?
>

Why use eval at all?

function ee($s) { return $s; }
$str = ee("Bob");
print $str;


JW

[iulian.ilea]

Re: eval problem


Janwillem Borleffs wrote:

iulian.ilea wrote:

By using eval I want to eval $v and get the result returned by ee
stored in $stri. How woul you do?

>
Why use eval at all?
>
function ee($s) { return $s; }
$str = ee("Bob");
print $str;
>
>
JW

Thanks, but what I wrote above is just an example. I take the variable
that must be eval'd from an sql table.

[Oli Filth]

Re: eval problem

iulian.ilea said the following on 24/09/2006 12:54:

Janwillem Borleffs wrote:

>iulian.ilea wrote:

>>function ee($s)
>> {
>> return $s;
>> }
>>>
>>$v="e(\"name\ ")";
>>>
>>eval("$stri=$ v;");
>>echo $stri;

>>By using eval I want to eval $v and get the result returned by ee
>>stored in $stri. How woul you do?
>>>

>Why use eval at all?
>>
>function ee($s) { return $s; }
>$str = ee("Bob");
>print $str;

>
Thanks, but what I wrote above is just an example. I take the variable
that must be eval'd from an sql table.

This leads to a further question: Why does your database contain PHP
code? This goes against normal practices of both database and PHP
design. You may be aware of the popular quotation:

"If eval() is the answer, you're almost certainly asking the wrong
question."

i.e. there's probably a better, safer, more programmatic way of doing
what you're doing.


However, the answer to your original problem is that if you want the
string literal '$stri', you must escape the $ character, i.e.:

eval("\$stri = $v;");

Otherwise the value of $stri is substituted into the expression to be
evaluated (and presumably at this point $stri doesn't exist).


--
Oli

[Colin McKinnon]

Re: eval problem

iulian.ilea wrote:

>
By using eval I want to eval $v and get the result returned by ee
stored in $stri. How woul you do?

Exactly the way its written in the manual (http://uk2.php.net/eval)

$v = 'e("name")';
$v="\$stri = " . $v . ";";
eval($v);
print $stri;

Eval (and storing code in a database) is very dangerous unless you know what
you're doing - and anyone who know what they were doing would RTFM first.
You have not done that therefore we must assume you don't know what you are
doing.

And if you did know what you were doing you would be trying very hard to
avoid the scenario where this is the solution.

C.

[Tim Roberts]

Re: eval problem

"iulian.ile a" <iulian.ilea@gm ail.comwrote:

>
>I have to eval a string stored in a variable, but it's not working.
>code:
>___
>
>function ee($s)
{
return $s;
}
>
>$v="e(\"name\" )";
>
>eval("$stri=$v ;");
>echo $stri;
>___
>
>By using eval I want to eval $v and get the result returned by ee
>stored in $stri. How woul you do?

Well, for one thing, I would not try to call a function called "e" when I
had named the function "ee".
--
- Tim Roberts, timr@probo.com
Providenza & Boekelheide, Inc.