Get parent function within class

Question

is following somehow possible? And if so how?! I know i could pass a parameter but I'd like it to be dynamic!

<?php

class my_class {

  protected $parent = NULL;

  public function __construct() {

    // now i'd like to get the name of the function where this class has been called
    $this->parent = get_parent_function();

  }

  public function parent() {
    return $this->parent;
  }

}

function some_random_function() {
  // Do something
  $object = new my_class();

  print $object->parent(); // returns: some_random_function
}

?>

Thanks in advance!

By "parent," do you mean the class that `my_class` extends? Because that's trivial: `parent::get_parent_function`. But it sounds like you're after something different... — sdleihssirhc, May 15 '11 at 15:49
Looks like bad design. May i ask, Why you would like to do this? — Alp, May 15 '11 at 15:51
@sdleihssirhc he's trying to get a reference to the function that is creating the object. — WirthLuce, May 15 '11 at 15:54
i'm trying to create a simple runtime cache class which uses the name of the function as key — n00b, May 15 '11 at 15:57
I think this is a duplicate of [How to get name of calling function/method in PHP?](http://stackoverflow.com/questions/2110732/how-to-get-name-of-calling-function-method-in-php "How to get name of calling function/method in PHP?") — WirthLuce, May 15 '11 at 16:09

score 5 · Accepted Answer · answered May 15 '11 at 16:02

Frankly this seems like a pretty bad design choice, however it would be possible to do this using call stack introspection using the PHP builtin debug_backtrace function. The following example is from the php documentation for debug_backtrace:

<?php
// filename: /tmp/a.php

function a_test($str)
{
    echo "\nHi: $str";
    var_dump(debug_backtrace());
}

a_test('friend');
?>

<?php
// filename: /tmp/b.php
include_once '/tmp/a.php';
?>

If b.php is executed, the output could look like this:

Hi: friend
array(2) {
[0]=>
array(4) {
    ["file"] => string(10) "/tmp/a.php"
    ["line"] => int(10)
    ["function"] => string(6) "a_test"
    ["args"]=>
    array(1) {
      [0] => &string(6) "friend"
    }
}
[1]=>
array(4) {
    ["file"] => string(10) "/tmp/b.php"
    ["line"] => int(2)
    ["args"] =>
    array(1) {
      [0] => string(10) "/tmp/a.php"
    }
    ["function"] => string(12) "include_once"
  }
}

If you were clever you could use the function name of the function in the backtrace to call it, e.g. debug_backtrace()[1]['function'](), but this will only work if the function is defined in the scope that you are currently executing in. See the php documentation on variable functions for more info on calling functions by their name from a string.

In my opinion, though, there should be no reason for you to do this in a well designed program. Perhaps you should think about using objects and references to objects instead.

score 1 · Answer 2 · answered May 15 '11 at 16:08

You could also use (even if there probably are better designs):

public function __construct($functionname = NULL) {
    $this->parent = $functionname; 
}

Then just:

function some_random_function() {
  // Do something
  $object = new my_class('some_random_function');

  print $object->parent(); // returns: some_random_function
}

score 0 · Answer 3 · edited May 23 '17 at 12:12

0

If you want to get the name of the function that called the constructor of my_class, you can use PHP's debug_backtrace as describe here:

How to get name of calling function/method in PHP?

edited May 23 '17 at 12:12

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answered May 15 '11 at 16:00

maxenglander

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Get parent function within class

3 Answers3