The point was more that the constant's value is 'defined' at the
beginning of the script, and is constant and non changing throughout
the entire execution of the script. But I was looking for a way to give
it a namespace inside a class rather than just defining in in the
global scope so that I do not have to worry about conflicting names
with other packages such as PEAR et al.
I wanted to do something like:
<?
define('ClassName::ConstantName',$valueDeterminedAtStartOfScript);
?>
so that I I could later use the notation
$value = ClassName::ConstantName
or from within the class
$value = self::ConstantName
and ensure other developers could not change the value of the constant.
To achieve the result I want I could do:
<?
define ('foo',$valueDeterminedAtStartOfScript);
class ClassName {
const ConstantName = foo;
}
?>
But that just seems pointless and messy. I will assume that the simple
answer to my original question was 'No that it is not possible'.
Thanks
- Jeff
Jeffrey Sambells
cell 519.897.2552
phone 905.878.4701
web http://www.sambells.info
On 7-Dec-05, at 1:22 PM, Jay Blanchard wrote:
[snip]
is there a way to dynamically define a class constant during runtime
in PHP 5?
for example I would like to achieve the result of something like:
class Example {
const FOO = bar();
}
However this would obviously give a parse error.
I know it is possible with variables but I would like it to be a
constant.
[/snip]
Well, first of all the syntax you describe above does not define a
constant
at all, you would need to use define()
The second thing is good old basic OOP theory, you should declare a
private
static variable
http://us3.php.net/private
http://us3.php.net/manual/en/language.oop5.static.php
Of course you could define a global constant and then pass it into your
object when instantiating it, but that is a bad idea generally.
Thirdly, you could never use a function to derive your constant
value...it
would then be an oxymoron. If the value generated by the function bar()
changes, FOO is a variable. Constants are for simple values. For
instance,
we can all agree that pi is 3.14159 (to 5 decimal places, so defining a
constant pi makes sense;
define("PI", 3.14159);
If we do not know what the outcome of a function will be it makes the
value
of the outcome a variable, always. It would be foolish (and would fail
anyhow) to do something like this;
define("RANDOM", rand(5,12));
