Re: Cooking with Perl explained by Iron Chef Macphisto

[Macphisto]

Okay, Being that I talk to zdog and really respect his level of programming skill, I decided I'd explain how this one went because while it's somewhat simple, zdog was very creative with it and I like it more than most.

First we'll make it look more recognizable and throw in some quick commentary

#!/usr/bin/perl -w            # cooking with perl -- "mmm I hope it's 
+pie"
use strict;
{
   $_.=<DATA>;           # read one line of <DATA>
   redo if !eof(DATA);   # read all of data into $_
}
s/[ \n3A-Z]//g;          # delete any newline, any digit '3'and any A-
+Z
s/000/032/g;                             # switch any 000 with a 032
my @z = split //;        # Puts $_ into the array @z  
for (my $i=0;$i<24;$i++) # 23 loops
{ 
  $_[@_] = "$z[@_*3]$z[@_*3+1]$z[@_*3+2]"  # Chops $_ into three digit
+ sections
}
my $z;
map $z .= chr($_),@_; # maps each three digit sequence into chr($_) to
+ create each letter in the japh 
$_ = $z."\n"; #Throws a new line to the end of the $z and stores it in
+to $_
print; # prints $_

Now for a line by line description:
Line 1-2 These are of course self explanatory
Line 3-6 This little construct will read all of <DATA> into $_ ending when DATA ends of course
Line 7 The regex here takes out all of the newlines, all the digits'3' and all any alpha numeric ( capital of course ). Which leaves us with the following string07411711511603209711011101161041011140320801011141000072097099107101114 ( hope I didn't miss any )
Line 8 Switches all 000's in the above string with 032
Line 9 Throw $_ into the array @z
Line 10-13 This for loops mercilessly hacks the digit string into sections of three digits. Giving us the following:

074
117
115
116
032
097
110
111
116
104
101
114
032
080
101
114
100
007
209
709
910
710
111
4

Line 14 Declares $z
Line 15 maps the character representation of each three digit piece into $z
Line 16 Adds a new line to $z and assigns it to $_
Line 17 Prints $_ and thus prints "Just Another Perl Hacker"

I was very impressed with this and hope my explination was adequate.

Iron Chef Macphisto
Next episode I'll show you how to make Perl Pie
Addendum: zdog noted that I had mistyped and said the for loop iterates 23 times when it really iterates 24 times. I was typing too fast.

Everyone has their demons....

[Sisyphus]

Thanks for the explanation, since then it was just easy to follow the code. ++votes for you and for zdog.

One more thing. As I got 'another' in lowercase (guess you made a typo in the explanation), and curious enough, I wondered what changes to introduce in the data to get a capital A. So I replaced the meaningless '3' and 'X' chars with hiphens, just to track down the '097' ASCII code. As it can be easily seen:



    -0-    --7---4-
    --1-  --1---7---1
    ---1---5---1---1---
    6---0---0--   -0---
   0---9---7---    1---
 1 -- -0---1---  1 ---1
  --  -1---1---6  ---1
        ---0---4-
        --1---0---1---1---1---4---0---0---0-
        --0---8---0---1---0---1---1---1---4--
         -1---0---8---0---0---0---0---7---2---0
          ---9---7---0---9---9---1---0---7---1---
           0---1---1---1---4------------------
             --------------------------------
              ------------------------------
                ---------------- ----------
                 ------           ----------
                  ----            ---   -----
                   ---              ---    ----
                    --               --      --
                    --               --      --
                    --              --       --
                    --             --        --
                  ---            ---        --


it is in line 5. Replaced it with '065' and I was done.

Where is the promissed Perl pie? :-)

-- Ricardo
use MacPerl;