Functions within functions

[portabletelly]

Hi I was wondering if it was possible to turn this bit of code into a function? I use it many times accross several different pages.

 

Basically the code is a dynamic select list which goes into a html form. What i was thinking was to turn it into a function and put it on a page by itself called select_customers.php then use include("select_customers.php") on the pages I requried it. Is this possible?

 

If so how would I turn this into a fuction

What syntax would I need to include the funtion on a seperate page.

 

Thanx in advanced

 

$query = "SELECT name FROM customer_tb";
$result = mysql_query($query, $link);
if(mysql_num_rows($result))
  		{
      // we have at least one user, so show all users as options in select form
      while($row = mysql_fetch_row($result))
      {
         print("<option value=\"$row[0]\">$row[0]</option>");
       //$test="while";
       }
    }
    else {
     //$test="else";
     print("<option value=\"\">No users created yet</option>");
    }

[AbydosGater]

<?php
function createList(){
$query = "SELECT name FROM customer_tb";
$result = mysql_query($query, $link);
if(mysql_num_rows($result))
   		{
       // we have at least one user, so show all users as options in select form
       while($row = mysql_fetch_row($result))
       {
          print("<option value=\"$row[0]\">$row[0]</option>");
        //$test="while";
        }
     }
     else {
      //$test="else";
      print("<option value=\"\">No users created yet</option>");
     }
} // End Function
?>

 

Then just include the file at the top of every page. And in the file where you want the code to run just add <? createList(); ?>

 

and it will run the code.

Hope this helps.

Andy

 

Edit: You have the title as Functions within functions, is that code already within a function?

[portabletelly]

I thought mysql_query($query, $link); was a function. Just wasnt sure how php would handle queryies within a funciton.

[Barand]

function returning the required code. try

<?php
function customer_select() 
{
    $res = '<select name="customer">';
    $query = "SELECT name FROM customer_tb";
    $result = mysql_query($query);
    if(mysql_num_rows($result))
   		    {
           // we have at least one user, so show all users as options in select form
           while($row = mysql_fetch_row($result))
           {
              $res .= "<option value=\"$row[0]\">$row[0]</option>";
            //$test="while";
            }
         }
         else {
          //$test="else";
          $res .= "<option value=\"\">No users created yet</option>";
         }  
         $res .= '</select>';
         
         return $res;
}

echo customer_select();
?>

[AbydosGater]

Yes it is a function!

PHP allows functions to be used within other functions.

 

I dont think you can create functions inside others IE:

But ive never had to try so i dont know.

function number1(){

  function number2(){

  //im inside another

  }

}

 

That code i posted before should work fine.

 

 

EDIT: Yeah sorry thanks Barand, I didnt see the return. If you going to run the code you must use <? echo customer_select(); ?> not just customer_select() sorry bout that.

[Barand]

You can

<?php
function foo($n)
{
     function bar($x) 
     {
        return $x * 10;
     }
     
     return bar($n);
}

echo foo(1);      // --> 10
?>

 

but a couple of things to be careful of

 

-- If you call bar() before you call foo() you get "Undefined function bar()" error

 

-- If you call foo() a second time you get "bar() already defined" error

[AbydosGater]

Ah, ok.. Well i dont think many people would be needing to do it. If it was absolutely needed im sure a class could be used.

Andy

[Barand]

A comment on mysql_query() inside a function.

 

If you use the optional $link argument then you need either to declare $link as global or pass it to the function.

 

Easier to omit it and the last connection is used by default.

[per1os]

A note on the function inside function. To defeate the error message of function already defined implement it like this =)

 

<?php
function foo($n)
{
     if (!function_exists('bar')) {
         function bar($x) 
         {
            return $x * 10;
         }
     }
     
     return bar($n);
}

echo foo(1);      // --> 10
?>

 

Basically it only defines the function once and does not break the code =)

[Barand]

I think it's a weakness of the language that you have to do that. If you declare a function within a function, then, like a variable declared inside a function, it should only be available within, and for the duration of, the outer function.

ie. Function scope, in this case, should be the same as variable scope.

[AbydosGater]

Yes, I Agree. Maybe we will see this in a newer version, Would be helpful to many.

 

Andy