This turned out not to be the disaster I expected

I was initially thinking about a module that would generate and execute every possible piece of Perl code when it was loaded. Such a module would be very useful, because once you loaded it, you wouldn't have to actually run your program; it would already have done whatever it was that you wanted.

As a first cut, I wrote:

   $s = "a";  while (length($s) < 100) { eval $s; $s++ }
[download]

realizing that this wasn't going to be what I wanted, because it doesn't generate any code with spaces or punctuation, but I thought it might be fun, at least as a joke. It looks like it is going to take a long time to execute, so I ran it with some fear that it might crash my machine or do something else bad.

But actually it executes rather quickly, and nothing bad happens. As I said, it was not the disaster I expected.

Can you predict the results?

--
Mark Dominus
Higher-Order Perl

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Re: This turned out not to be the disaster I expected by imp (Priest) on Jun 06, 2007 at 19:39 UTC
It would call dump since that's the first command it would come across that would force an exit. Next up would be exec and exit.	[reply]
Re^2: This turned out not to be the disaster I expected by kyle (Abbot) on Jun 06, 2007 at 19:45 UTC
Actually, it looks as if exec does not do the job. I get "foo" from: `perl -le '$x="exec";eval $x;print "foo";'` [download] Not so for dump and exit.	[reply] [d/l]
Re^2: This turned out not to be the disaster I expected by FunkyMonk (Bishop) on Jun 06, 2007 at 19:50 UTC
... and takes a breather at <Reveal this spoiler or all in this thread> No exit with exec though. perldoc exec only mentions `exec LIST exec PROGRAM LIST` [download]	[reply] [d/l]
Re: This turned out not to be the disaster I expected by kyle (Abbot) on Jun 06, 2007 at 19:41 UTC
<Reveal this spoiler or all in this thread> Doh, I see imp beat me to it, and with a better answer to boot.	[reply]
Re: This turned out not to be the disaster I expected by shmem (Chancellor) on Jun 06, 2007 at 21:36 UTC
<Reveal this spoiler or all in this thread> --shmem _($_=" "x(1<<5)."?\n".q·/)Oo. G°\ / /\_¯/(q / ---------------------------- \__(m.====·.(_("always off the crowd"))."· ");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}	[reply] [d/l]
Re: This turned out not to be the disaster I expected by BrowserUk (Patriarch) on Jun 06, 2007 at 19:37 UTC
<Reveal this spoiler or all in this thread> Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply]
Re^2: This turned out not to be the disaster I expected by imp (Priest) on Jun 06, 2007 at 19:41 UTC
<Reveal this spoiler or all in this thread>	[reply]
Re: This turned out not to be the disaster I expected by naikonta (Curate) on Jun 07, 2007 at 02:53 UTC
This can be a way to find a c00l n4m3 or some magic number? `perl -le '$s = shift; while (length($s) < 100) { print $s; eval $s; $s +++; }'` [download] But this one is less fun :-) `perl -le '$s = shift; while (length($s) < 100) { print $s; eval $s; $s +++; }' 'kill 9, $$'` [download] Open source softwares? Share and enjoy. Make profit from them if you can. Yet, share and enjoy!	[reply] [d/l] [select]
Re: This turned out not to be the disaster I expected by djp (Hermit) on Jun 07, 2007 at 03:03 UTC
I'm predicting you hit '?' early in the piece. Update: didn't hide my answer as others did.	[reply]
Re^2: This turned out not to be the disaster I expected by jdporter (Paladin) on Jun 07, 2007 at 13:19 UTC
No, because magical autoincrement on alphanumeric strings never strays outside the alphanumeric character set.	[reply]
Re: This turned out not to be the disaster I expected by ambrus (Abbot) on Jun 10, 2007 at 00:23 UTC
<Reveal this spoiler or all spoilers in this node or all in this thread> Update: Ok, let me think this over again after reading the other replies. <Reveal this spoiler>	[reply] [d/l] [select]
Re: This turned out not to be the disaster I expected by gaal (Parson) on Jun 07, 2007 at 16:29 UTC
I seem to vaguely recall someone discovering this sometime in the 90ies, maybe even on c.l.p.m.	[reply]
Re: This turned out not to be the disaster I expected by diotalevi (Canon) on Jun 09, 2007 at 00:29 UTC
It leaks memory while it's working. ⠤⠤ ⠙⠊⠕⠞⠁⠇⠑⠧⠊	[reply]