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Date: Thu, 10 Jan 2008 19:09:26 +0900
To: internals@lists.php.net
Cc: "Marcus Boerger" <helly@php.net>
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Subject: [RFC] Anonymous functions
From: rsky0711@gmail.com ("Ryusuke SEKIYAMA")

Hello, lists,

We have discussed about implementing anonymous functions and
closures in PHP.
However, I consider that implementing anonymous functions and
implementing lexical scopes should be discussed separately.
# Even though I like closure. ;-)
So I wrote anonymous function patch for PHP 5.3 and 6.0.


Patches (inlcude tests):
for PHP 5.3: http://www.opendogs.org/pub/php-5.3dev-080109-anon.patch
for PHP 6.0: http://www.opendogs.org/pub/php-6.0dev-080109-anon.patch


Featues:
- Unlike create_function(), there is no need to take care of
  quotes, backslashes and dollars .
- Can be used in loop, but be compiled only once.
- Supports recursive call using __FUNCTION__.
- Supports inline execution. It works like a block scope.
- Works with opcode caches.
  Since I couldn't build APC against PHP 5.3, I have tested
  PHP 5.2.5 + anonymous function patch and APC 3.0.16.


Example:
<?php
// callback
$arr = array(5, 3, 6, 0);
usort($arr, function($a, $b){ return $a - $b; });
print_r($arr); // 0, 3, 5, 6

// assign to a variable
$lambda = function(){
  echo "Hello, World!\n";
};
$lambda(); // "Hello, World!"

// inline execution
$result = function($a, $b){
  return $a + $b;
}(1, 2);
var_dump($result); // "int(3)"
?>


The anonymous function name is composed of '\0', "ZEND_ANON<#serial>",
filename and character position.
- Leading '\0' blocks to be displayed by get_defined_functions().
- "ZEND_ANON<" helps determine wheter the function is anonymous or not
  because '<' cannot be used for user-defined function name.
- Serial number and file informations make the name unique.
- char anon_key_buf[32] is long enough because
  `snprintf(anon_key_buf, 32, "ZEND_ANON<%llu>", (unsigned long
long)UINT64_MAX)'
  returns 31.


Regards,


2008/1/6, Marcus Boerger <helly@php.net>:
> Hello Stanislav,
>
>   tha makesw three then already, how about we ask around again?
> Ryusuke, can you please start a new '[RFC] Square brackets shortcut' thread
> to collect opinions and pass along the patch for that?
>
> I like the anonymous function patch too. It is clean and simple. Maybe you
> want to start a second '[RFC] Anonymous functions' thread with that patch.
>
> Can you also please add tests for both?
>
> marcus
>
> Wednesday, January 2, 2008, 7:51:06 PM, you wrote:
>
> >> the square bracket array syntax patch for PHP 5.3,
> >>   http://www.opendogs.org/pub/php-5.3dev-080101-sbar.patch
>
> > I remember we discussed that already and it was rejected then (even
> > though myself and Andi liked it) - did the people that objected then
> > change their minds?
>
>
>
> Best regards,
>  Marcus
>
>


-- 
/**
 * Ryusuke SEKIYAMA
 * rsky0711@gmail.com
 */