On Wed, Aug 18, 2010 at 12:23 PM, Ashley Sheridan
<ash@xxxxxxxxxxxxxxxxxxxx>wrote:
> Hi list,
>
> I know that some languages such as C++ can overload functions and
> methods by declaring the method again with a different number of
> arguments, and the compiler internally sorts things out, but I can't
> seem to find a similar way to do this with PHP.
>
> Basically, what I've got at the moment is a class method with 2
> arguments, and I need to be able to overload the method with 3
> arguments. The following which would work in other languages doesn't
> seem to bring any joy in PHP:
>
> class foo
> {
> public function bar($arg1, $arg2)
> {
> // do something with $arg1 & $arg2
> }
>
> public function bar($arg1, $arg2, $arg3)
> {
> // do something different with all 3 args
> }
> }
>
> Is there any feasible way of doing this? The method names really need to
> remain the same as they exist as part of a framework, but the arguments
> really server quite different purposes between the two methods, so
> there's no nice way of just merging the two functions without breaking
> the naming conventions, etc used.
>
> Thanks,
> Ash
> http://www.ashleysheridan.co.uk
>
>
>
Hi Ashley,
Sorry for a slow reply, but I've found a free second and I'd like to toss
out the scheme I've used most often.
If args 1 and 2 are consistent in terms of type and usage across the two
methods, I simply add arg3 with a default to null and conditionally call a
private method that performs the special operation (documentation and
primary entry point remain in one place. Essentially, I just add a guard
clause to the original function. The
class foo
{
public function bar($arg1, $arg2, $arg3 = null)
{
if (!is_null($arg3)) return _specialbar($arg1, $arg2, $arg3);
// do something with $arg1 & $arg2
}
public function _specialbar($arg1, $arg2, $arg3)
{
// do something different with all 3 args
}
}
If, however, the functions differ significantly in terms of signature, I
tend to write a wrapper function that chooses the appropriate internal call
(e.g., newbar()), but this doesn't play too nicely with documentation within
the PHP ecosystem (although within other language systems such as Java, C#,
and Erlang, it's really quite nice and elegant), so I tend to structure my
code to make use of option one when possible.
Adam
--
Nephtali: PHP web framework that functions beautifully
http://nephtaliproject.com
