Variable Argument Function Calls

[Adam]

Hey,

Just a quick appeal for suggestions re some code, able to pass varying
numbers of arguments...

I have a function which can accept varying numbers of arguments. It in
turn calls a function whose argument list can vary in length.

At the moment, I have something along the lines of...

************************************************** **********
function varargsfunction(){

switch(func_num_args()){
case 0:
$value = function($inputargs[0]);
break;

case 1:
$value = function($inputargs[0], $inputargs[1]);
break;

case 2:
$value = function($inputargs[0], $inputargs[1], $inputargs[2]);
break;

etc.......

}

return otherfunction($value);

}
************************************************** **********

It works fine, but I am obviously restricted by the length of my case
statement. Also, as you can see it's not a very pretty solution!!

Is there a way to dynamically build the argument list such that it does
not require me to write out every possible case into a big switch
statement?
Any help greatly appreciated!!
Thanks in advance.
Adam.

[Rik]

Adam wrote:

Hey,

Just a quick appeal for suggestions re some code, able to pass varying
numbers of arguments...

I have a function which can accept varying numbers of arguments. It
in turn calls a function whose argument list can vary in length.

At the moment, I have something along the lines of...

************************************************** **********
function varargsfunction(){

switch(func_num_args()){
case 0:
$value = function($inputargs[0]);
break;

Euhm, this should break immedietaly.
From func_num_args() = 1 on, you can use

case 1:
$value = function($inputargs[0], $inputargs[1]);
break;

case 2:
$value = function($inputargs[0], $inputargs[1], $inputargs[2]);
break;

etc.......

}

return otherfunction($value);

}
************************************************** **********

It works fine, but I am obviously restricted by the length of my case
statement. Also, as you can see it's not a very pretty solution!!

Is there a way to dynamically build the argument list such that it
does not require me to write out every possible case into a big switch
statement?

<?php
function test($var1,$var2,$var3){
echo "$var1 $var2 $var3\n";
}

function varargsfunction(){
$array = func_get_args();
return call_user_func_array('test',$array);
}
varargsfunction('test1'); //issues a warning: missing parameters
varargsfunction('test1','test2','test3'); //this works
varargsfunction('test1','test2','test3', 'test4'); //this works, argument 4
is ignored
?>

Grtz,
--
Rik Wasmus

[Jerry Stuckle]

Adam wrote:

Hey,

Just a quick appeal for suggestions re some code, able to pass varying
numbers of arguments...

I have a function which can accept varying numbers of arguments. It in
turn calls a function whose argument list can vary in length.

At the moment, I have something along the lines of...

************************************************** **********
function varargsfunction(){

switch(func_num_args()){
case 0:
$value = function($inputargs[0]);
break;

case 1:
$value = function($inputargs[0], $inputargs[1]);
break;

case 2:
$value = function($inputargs[0], $inputargs[1], $inputargs[2]);
break;

etc.......

}

return otherfunction($value);

}
************************************************** **********

It works fine, but I am obviously restricted by the length of my case
statement. Also, as you can see it's not a very pretty solution!!

Is there a way to dynamically build the argument list such that it does
not require me to write out every possible case into a big switch
statement?
Any help greatly appreciated!!
Thanks in advance.
Adam.

Why not let the functions take an array? That way you can have as many
or few parameters as you wish.
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
js*******@attglobal.net
==================

[Rik]

Jerry Stuckle wrote:

Adam wrote:

>Hey,

Just a quick appeal for suggestions re some code, able to pass
varying numbers of arguments...

I have a function which can accept varying numbers of arguments. It
in turn calls a function whose argument list can vary in length.

<snip code>

>It works fine, but I am obviously restricted by the length of my case
statement. Also, as you can see it's not a very pretty solution!!

Is there a way to dynamically build the argument list such that it
does not require me to write out every possible case into a big
switch statement?

Why not let the functions take an array? That way you can have as
many or few parameters as you wish.

While offcourse a better idea, one might want to adress an already existing
PHP function, where the behaviour cannot be altered easily. But in that
case, a simple call_user_func_array() in the code itself should suffice,
instead of making it a different function.

We might have better insight if the OP could explain what the function
should actually do.

Grtz,
--
Rik Wasmus

[Adam]

Thanks for your help so far... I had to type it from memory, so agree
that the "case 0:" was dead wrong!
The reason for using the multi arg input is twofold...

1. I am placing the vars into sprintf (to construct a MySQL query)
which is itself a variable arg function (hence why I don't think I can
use an array here).

2. Using an array just means I need a few extra lines of code to move
all of the random query bits into an intermediate array to stick into
the function. I would prefer to be able to list them in the function
call.

I am aware that there are other ways to do this, but I am aiming for an
ultra elegant solution. Maybe I'm being a bit pedantic about it!?! : )
Cheers again...
Adam

Rik wrote:

Jerry Stuckle wrote:

Adam wrote:

Hey,

Just a quick appeal for suggestions re some code, able to pass
varying numbers of arguments...

I have a function which can accept varying numbers of arguments. It
in turn calls a function whose argument list can vary in length.

<snip code>

It works fine, but I am obviously restricted by the length of my case
statement. Also, as you can see it's not a very pretty solution!!

Is there a way to dynamically build the argument list such that it
does not require me to write out every possible case into a big
switch statement?

Why not let the functions take an array? That way you can have as
many or few parameters as you wish.

While offcourse a better idea, one might want to adress an already existing
PHP function, where the behaviour cannot be altered easily. But in that
case, a simple call_user_func_array() in the code itself should suffice,
instead of making it a different function.

We might have better insight if the OP could explain what the function
should actually do.

Grtz,
--
Rik Wasmus

[Rik]

Adam wrote:

Thanks for your help so far... I had to type it from memory, so agree
that the "case 0:" was dead wrong!

The reason for using the multi arg input is twofold...

1. I am placing the vars into sprintf (to construct a MySQL query)
which is itself a variable arg function (hence why I don't think I can
use an array here).

Euhm. vsprintf()? Takes an array, loves it actually.

2. Using an array just means I need a few extra lines of code to move
all of the random query bits into an intermediate array to stick into
the function. I would prefer to be able to list them in the function
call.

I am aware that there are other ways to do this, but I am aiming for
an ultra elegant solution. Maybe I'm being a bit pedantic about
it!?! : )

Well, the best I can do to achieve what I think you want:
Call an arbitrary function with an arbitrary amount of arguments, switching
scalars and arrays like it doesn't care, the first argument given is the
function, be it in a scalar or the first scalar in the first array (of the
first array and so forth):

<?php

function flatten_array($arg){
if(!is_array($arg)) return array($arg);
$return = array();
foreach($arg as $row){
if(is_array($row));
$return = array_merge($return,flatten_array($row));
} else {
$return[] = $row;
}
}
return $return;
}

function varargsfunction(){
$array = func_get_args();
$array = flatten_array($array);
$function = array_shift($array);
return call_user_func_array($function,$array);
}
?>

Grtz,
--
Rik Wasmus

[Adam]

Thanks Rik, that's exactly what I was after!

Cheers,
Adam.
Rik wrote:

Adam wrote:

Thanks for your help so far... I had to type it from memory, so agree
that the "case 0:" was dead wrong!

The reason for using the multi arg input is twofold...

1. I am placing the vars into sprintf (to construct a MySQL query)
which is itself a variable arg function (hence why I don't think I can
use an array here).

Euhm. vsprintf()? Takes an array, loves it actually.

2. Using an array just means I need a few extra lines of code to move
all of the random query bits into an intermediate array to stick into
the function. I would prefer to be able to list them in the function
call.

I am aware that there are other ways to do this, but I am aiming for
an ultra elegant solution. Maybe I'm being a bit pedantic about
it!?! : )

Well, the best I can do to achieve what I think you want:
Call an arbitrary function with an arbitrary amount of arguments, switching
scalars and arrays like it doesn't care, the first argument given is the
function, be it in a scalar or the first scalar in the first array (of the
first array and so forth):

<?php

function flatten_array($arg){
if(!is_array($arg)) return array($arg);
$return = array();
foreach($arg as $row){
if(is_array($row));
$return = array_merge($return,flatten_array($row));
} else {
$return[] = $row;
}
}
return $return;
}

function varargsfunction(){
$array = func_get_args();
$array = flatten_array($array);
$function = array_shift($array);
return call_user_func_array($function,$array);
}
?>

Grtz,
--
Rik Wasmus