I had an idea, and as I worked on it, two forms emerged.

Blessed Objects:

$"='|';$|=$d=1;@b=map{bless{t,"$_  ",r,$d*=-1}}qw/Just another Perl
hacker,/;sub v{$s=shift;my$_=$$s{t};$r=int y===c*$$s{a}/360;$$s{a}=
($$s{a}+$$s{r})%360;s%(.{$r})(.*)%$2$1%;$_}{print"\r@{[map{v$_}@b]
}";select$x,$y,$z,2e-3;redo}

[download]

This section doesn't contain spoilers per se, but a discussion of how it evolved.

It should come as no surprise as you look it over that it started out as a relatively clean implementation of a class that gets instantiated into several blessed objects. There were the usual accessors and the usual call to a subroutine designated as a constructor.

Little by little I found chunks that could be removed, condensed, written a more obscure way, and so on. In some cases member functions that were used only once got inlined into a single member function. Then the constructor got pulled out of the customary function and into a loop's block. In the end, I got 228 keystrokes (231 if you count newlines, which are significant), and something pretty funky.

If I had stopped there, all I would have posted would be the preceding code and a little wisecrack or something.

But then I started thinking about the fact that with Perl, functions can be used as first class objects themselves thanks to closures and subrefs. (Obviously this isn't a new discovery, but it's sometimes overlooked.) This seemed like a perfect example of where that sort of approach could work out nicely. That idea led to a second quest, and here's how it turned out."

Functional Objects:

$"='|';$|=$d=1;@b=map{my($t,$h,$a)=("$_  ",$d*=-1);sub{my$_=$t;$r=int
y===c*$a/360;$a=($a+$h)%360;s%(.{$r})(.*)%$2$1%;$_}}qw/Just another
Perl hacker,/;{print"\r@{[map{&$_}@b]}";select$x,$y,$z,2e-3;redo}

[download]
<Reveal this spoiler or all spoilers in this node or all in this thread>

The extra discussion may be unconventional for this sort of post, but I just enjoyed the process and felt like sharing a little about it.

Enjoy!


Dave

Replies are listed 'Best First'.
Re: Objects: Classical and Functional
by ambrus (Abbot) on Oct 25, 2011 at 09:42 UTC

    How to see what this actually prints? 

    $ perl a2.pl | tr \\r \\n | uniq

Just  |another  |Perl  |hacker,  
 Just |another  | Perl |hacker,  
 Just |nother  a| Perl |acker,  h
  Just|nother  a|  Perl|acker,  h
  Just|other  an|  Perl|cker,  ha
  Just|ther  ano|  Perl|ker,  hac
t  Jus|ther  ano|l  Per|ker,  hac
t  Jus|her  anot|l  Per|er,  hack
st  Ju|her  anot|rl  Pe|er,  hack
st  Ju|er  anoth|rl  Pe|r,  hacke
st  Ju|r  anothe|rl  Pe|,  hacker
ust  J|r  anothe|erl  P|,  hacker

    [download]
    …

    Also, it turns out the bless isn't even necessary. I replaced it with + and the code still works. I'm a bit disappointed.

[reply]
[d/l]
[select]
[reply]
Re: Objects: Classical and Functional
by ambrus (Abbot) on Oct 25, 2011 at 18:45 UTC

    Here's another variant. (This works only on perl 5.14 or newer.) 

    $_="\rH48lpt|nFfb^62RN|1eQ=qu|KkC?;[WwO"; 
select$,,q,,,q$$,3/y$4-w0-3$0-w$while$|=print y(0-{)
"JPr,ueersrhetltk  oc  naJPahue  sr  tlr,  er  heJPtkueocsrnatlah "r

    [download]
[reply]
[d/l]

Back to Obfuscated Code