classes and variable scope

[Joe Molloy]

Hi,

I'm wondering is there any way I can get a variable's value from within a
class when the variable has been declared outside the class but in the same
script as the class is contained in. For example, say I have the following
script

<?php
constant myvar = "my original string";

class myClass
{
function returnmyvar()
{
return "some processed text and ".$myvar;
}

function usesnewstr()
{
echo $this->returnmyvar();
}
}

$myCls = &New myClass($myvar);
$myCls -> usesnewstr();
?>
Now what I'd like this to output would be:
some processed text and my original string
but all I get is:
some processed text and

Now I know I could make a constructor function and pass $myvar in that way
but I would rather not have to do that as that would entail changing the
instatiation statements whevever that class is already used. Any other ways
to make $myvar visible to functions inside the class?

Joe

[ZeldorBlat]

First of all, in the example you provided, myvar is a constant, not a
variable. So if you ever try to get to it with $myvar you'll likely
get some sort of error or warning.

Constants and variables behave differently when looking at them from
another scope. When you define a constant in the global scope (that
is, outside of a class or function), it is available
everywhere...period. When you define a variable in the global scope,
it is available in the global scope as you would expect.

However, when you are in a different scope, such as a function or
class, global variables won't just "show up" automatically. You can
get to it, however, using either of the following methods:

//First method:
global $myvar; //$myvar is the global myvar
$x = $myvar; //$x gets the value from the global variable "myvar"

//Second method:
$x = $_GLOBALS['myvar']; //$x gets the value from the global variable
"myvar"

While I'm not entirely positive, I believe that the first one makes the
local $myvar a *reference* to the global $myvar. In other words, if
you change the value of $myvar from within that function and return to
the global scope, you'll find that $myvar has the new value.

If myvar is a constant, you can get to him from anywhere (the script, a
class definition, or a function) by just writing:

$x = myvar; //no $ since myvar is a constant

[Meião]

you can always use
(in PHP4)

class myClass{
function myClass($myvar = 'my original string'){
echo 'whatever ' . $myvar;
}
}

or something like that

[Siv Hansen]

Joe Molloy wrote:

Hi,

I'm wondering is there any way I can get a variable's value from within a
class when the variable has been declared outside the class but in the same
script as the class is contained in. For example, say I have the following
script

<?php
constant myvar = "my original string";

class myClass
{
function returnmyvar()
{
return "some processed text and ".$myvar;
}

function usesnewstr()
{
echo $this->returnmyvar();
}
}

$myCls = &New myClass($myvar);
$myCls -> usesnewstr();
?>
Now what I'd like this to output would be:
some processed text and my original string
but all I get is:
some processed text and

Now I know I could make a constructor function and pass $myvar in that way
but I would rather not have to do that as that would entail changing the
instatiation statements whevever that class is already used. Any other ways
to make $myvar visible to functions inside the class?

Joe

how about
function returnmyvar(){
return "some processed text and ". $this->myvar;
}

[Joe Molloy]

Thanks for all the tips - the $_GLOBALS function looks the most applicable
in my situation - I'm comming into some previously written code and don't
want to have to reinvent the wheel :)

Joe

"Joe Molloy" <mo********@hotmail.com> wrote in message
news:Hr*****************@news.indigo.ie...

Hi,

I'm wondering is there any way I can get a variable's value from within a
class when the variable has been declared outside the class but in the
same script as the class is contained in. For example, say I have the
following script

<?php
constant myvar = "my original string";

class myClass
{
function returnmyvar()
{
return "some processed text and ".$myvar;
}

function usesnewstr()
{
echo $this->returnmyvar();
}
}

$myCls = &New myClass($myvar);
$myCls -> usesnewstr();
?>
Now what I'd like this to output would be:
some processed text and my original string
but all I get is:
some processed text and

Now I know I could make a constructor function and pass $myvar in that way
but I would rather not have to do that as that would entail changing the
instatiation statements whevever that class is already used. Any other
ways to make $myvar visible to functions inside the class?

Joe

[Joe Molloy]

Actually, in the end, the code that worked looked like this for anyone else
in a similar situation:

<?php
$myvar = "my original string";

class myClass
{

var $mystr;

function myClass()
{
global $myvar;
$this -> mystr = $myvar;
}

function returnmyvar()
{
return "some processed text and ".$this -> mystr;
}

function usesnewstr()
{
echo $this->returnmyvar();
}
}

$myCls = &New myClass();
$myCls -> usesnewstr();
?>

Next week, inheritence ;)

Joe
"Joe Molloy" <mo********@hotmail.com> wrote in message
news:Hr*****************@news.indigo.ie...

Hi,

I'm wondering is there any way I can get a variable's value from within a
class when the variable has been declared outside the class but in the
same script as the class is contained in. For example, say I have the
following script

<?php
constant myvar = "my original string";

class myClass
{
function returnmyvar()
{
return "some processed text and ".$myvar;
}

function usesnewstr()
{
echo $this->returnmyvar();
}
}

$myCls = &New myClass($myvar);
$myCls -> usesnewstr();
?>
Now what I'd like this to output would be:
some processed text and my original string
but all I get is:
some processed text and

Now I know I could make a constructor function and pass $myvar in that way
but I would rather not have to do that as that would entail changing the
instatiation statements whevever that class is already used. Any other
ways to make $myvar visible to functions inside the class?

Joe

[ZeldorBlat]

That's fine but it's worth noting that, once myClass has been
instantiated, any changes to $myvar in the global scope will not be
reflected in the member variable of the object. This can be changed by
changing:

$this -> mystr = $myvar;

in the constructor to:

$this->mystr =& $myvar;

I think that should work -- although I didn't test it.