Yet another small programming challenge.

[Weedpacket]

The job is to write a PHP script which outputs its own source code. What comes out should be identical to what went in.

Testing will be via CLI:

php -f your_entry.php > your_result.php

your_entry.php and your_result.php will then be compared to see if they are the same program. As ever, running will be under E_ALL conditions, and try to stick to the core functionality of a typical PHP build (I won't be able to run it if you use SESAM functions...).

To make it a bit more challenging than a simple

<?php readfile(__FILE__)?>

(gee, don'tcha just love power?) or (to take an extreme, yet otherwise valid, example) a zero-length file, there are two provisos:

1. No file-related functions are to be used. This includes workarounds à la eval('r'.'e'.'a'.'d'.'f'.'i'.'l'.'e'.'('.''.''.'F'.'I'.'L'.'E'.''.''.')'.';');. Put simply: No reading files; no writing files. This includes databases.

2. There has to be some PHP code used.

I'll be lenient on whitespace; if I can't verify success by eye, I'll use a whitespace-insensitive diff. I might also do something with get_all_tokens(). Getting the whitespace right will of course be considered a bonus.

Elegance and simplicity count at least as much as brevity. That said, a bit of obfuscation is always good for a giggle. Laying out your source to make a pretty picture will also be smiled on (especially if the layout is retained in the output!).

If you like, you can also offer entries under variants of the challenge, if you say what the variation is to allow verifying that it's doing what it's supposed to. An example might be to have the script generate versions of itself which are identical except that variable and function names are created at random or according to some other criterion. Another might be a script A that generates a different script B that generates A.

[Shrike]

What about highlight_file(), highlight_string() ? 🙂

[Weedpacket]

[man]highlight_file[/man] reads a file. Disallowed. (I'll just go back and change a word there).

[Sgarissta]

I take it cat $argsv[0] isn't allowed either? 😉

[bad76]

Hi all, this is my entry...

<?php
$mine=Array(3,49... line cut for post ...50,-1);

$ban=ord('<');
for($i=0;$i<18;$i++)
{
	echo chr($ban);
	$ban+=$mine[$i];
}
$j=0;
foreach($mine as $dato)
{
	if($j==0) echo $dato;
	else echo ",".$dato;
	$j++;
}
for($i=18;$i<count($mine)-105;$i++)
{
	echo chr($ban);
	$ban+=$mine[$i];
}
echo "bite me";
for($i=count($mine)-105;$i<count($mine);$i++)
{
	echo chr($ban);
	$ban+=$mine[$i];
}
echo chr($ban);
?>

I've cutted the line because was too long for the post. But there is the full version in the file I've attached.

see you soon!

[piersk]

Just out of question, is this still an "inbetweener" whilst waiting for goldbug to finish judging the calendar competition :glare:

(sorry gb, had to comment on it somewhere...)

[bad76]

ehm...
maybe I'm missing something, but when is the dead-line?

I hint for tonight... :p

wait, I try again... "when expires this compo?"
bye bye

[bubblenut]

I'll admit it, I just kinda butchered it from a java example I found. It's about the shortest you can get to though I think.

<?php 
$s='<?php $s=;
$c=chr(39);
echo(substr($s,0,9).$c.$s.$c.substr($s,9));
?>';
$c=chr(39);
echo(substr($s,0,9).$c.$s.$c.substr($s,9));
?>

[bubblenut]

I felt a bit cheeky just butchering one which had been written in another language so I came up with my own based on the same principles. It's a MakeSelf class, the file also takes a single parameter which controls how many times it outputs its self.

Earlier today I found an article which outlined (and linked to more detail) a method involving some special recursive theory but I can't for the life of me find it now. When this is all done and gone can someone post a similar link (assuming anyine knows of one)

[edit]Actually tested it this time 🙂[/edit]

[Weedpacket]

Originally posted by Sgarissta
I take it cat $argsv[0] isn't allowed either? 😉

Now, what did I say about "reading files"? 🙂 I try so hard to rule out copouts, and someone has to try something on 🙂 All the merrier.

bubblenut, re. Quine2: First run gives an Undefined offset notice (line 55), and running the generated code gives a parse error.