[ot] Perl (was: ASCII art from sourcecode as image)

Arthur J. O'Dwyer wrote:
> 
> On Thu, 17 Jul 2003, Harry Mason wrote:
>>
>> Arthur J. O'Dwyer wrote:
>> > On Wed, 16 Jul 2003, Harry Mason wrote:
>> >> #!/usr/bin/perl -w
>> >> eval eval '"'.                          ('#').
>> >>                                        '!'.'/' .('['
>> ><snip most of very nice program>
>> >
>> > The OP has told me via e-mail that he really wants Java, of course.
>> > So unfortunately the 'eval big_long_string' trick that I think is
>> > at the root of EyeDrops' approach wouldn't work.
>>
>> Bear in mind that this is actually an obfuscator, not just a reformatter.
>> You could achieve a similar effect in most languages, including Java, by
>> creative use of white space, string concatenation, etc.
> 
> Certainly not in C or C++, and not in the vanilla beginner's Java I'm
> familiar with.  They don't have any equivalent of "eval", unless you
> build your own interpreter on top of everything. :)

Even without eval(), you can still rename variables, concatenate strings,
and insert comments.

                import                
         java.io.PrintStream;         
      public class ASmileyFace {      
   public static void main(String[]   
 a) { PrintStream out = System.out ;  
 out.print(     "This"     + " is " + 
 "both a "        +         "reform"+ 
 "atted J"    +  "av"  +    "a prog"+ 
 "ram, an"        +         "d a sm"+ 
 "i".concat(   "ley " +   "face. Th"+ 
 "is "    + "shows how to " +    "f"+ 
   "orm"     + "at Jav" +     "a "+   
     "usi"                  +"n"+     
        "g whitespace only.")         
                ) ;} }                

As for C, I expect you can find some examples at the IOCCC:
http://www.ioccc.org/

>> > And what does ('['^'.') mean?  0x5B^0x2E = 0x75 = 'u', or is there some
>> > deeper magic at work here? :)
>>
>> ('['^'.') corresponds to the "u" in "use strict". Obfuscating is so much more
>> effective if you don't use any alphanumerics in your source code. :)
> 
> Yeah - but does Perl specify ASCII?  And in a language where x is an
> operator, I wasn't sure but that ^ meant something even weirder for
> strings...

It's just doing bitwise XOR on the ASCII values of each character. See the
section "Bitwise String Operators" in perlop(1). Perl source code is ASCII
unless you add "use utf8;"; then it can be UTF-8 - but doing bitwise
operations on UTF-8 strings will no doubt get you into trouble one day. :)

-- 
|  Harry Mason  | .------------. |    .___,    |"Whatever you do will be |
| University of | |  hjm200 @  | | ___('v')___ | insignificant. However, |
|  Southampton  | | zepler.net | | `"-\._./-"' | it is vitally important |
|    England    | '------------' | hjm ^ ^     | that you do it." Gandhi |

Related ASCII art in the Gallery

Explore these categories from our collection of 11,000+ artworks:

    \\__  o
|\/    o\  o
>       < o
|/\   __/
    //

 |\__/,|   (`\
 |_ _  |.--.) )
 ( T   )     /
(((^_(((/(((_/

  , _ ,
 ( o o )
/'` ' `'\
|'''''''|
|\\'''//|
   """

 ,~~--~~-.
+      | |\
|| |~ |`,/-\
*\_) \_) `-'

 __
 \  \     _ _
  \**\ ___\/ \
X*#####*+^^\_\
  o/\  \
     \__\

.------------.
|\\//\\//\\//|
|//\\//\\//\\|
|\\//\\//\\//|
|//\\//\\//\\|
'------------'

Make your own ASCII art

Turn images, text or 3D into ASCII, or draw your own – right in your browser.