0: I don`t know if this is Craft, or a hack, I DO know that
1: it comes in handy (For me, since I am not a complete master 
2: of regular expressions (not until japhy's) book at least ;))
3: 
4: I am sure there is something like this out there, but I haven`t
5: bothered to look (sometimes it is just more fun to do something 
6: yourself ;)
7: 
8: What does it do ?
9: 
10: It draws you a little Tk window, and allows you to enter a string
11: and let a RegEx loose on it.
12: Dynamically the result of the RegEx is shown, and updated, so you
13: can see exactly what the result is of a change in the RegEx, or the
14: string.
15: 
16: TODO: 
17: 
18:      - Do something about that UI! ;)
19:      - Put an another eval in the function so $1..n are really
20:        1..n, instead of 1..5 ;)
21:      - Support for @+ @-
22:      - Clean up code ;)
23:      - Loads of stuff
24: 
25: Code will be updated soon, I hope ;)
26: 
27: Update: Implemented List context feature, as suggested by Jepri
28: 
29: The Code: 
30: #!/usr/bin/perl -w
31: use strict;
32: use Tk;
33: 
34: sub KeyPress;
35: 
36: my $MW=MainWindow->new;
37: 
38: my $AsList;
39: my %Border=qw(-relief raised);
40: my %Fill=qw(-fill both);
41: 
42: my $Top   =$MW->Frame->pack(-side=>'top');
43: my $TopLeft  =$Top->Frame(%Border)->pack(-side=>'left');
44: my $TopRight =$Top->Frame(%Border)->pack(-side=>'left');
45: 
46: my $RegLabel=$TopLeft->Label(%Border,-text=>'RegExp')->pack(%Fill);
47: my $TextLabel=$TopLeft->Label(%Border,-text=>'Text')->pack(%Fill);
48: my $AsListBox=$Top->Checkbutton(-text=>'List context',-variable=>\$AsList,-command=>\&KeyPress)->pack();
49: $Border{-bd}=1;
50: my $RegExp=$TopRight->Entry(-width=>30)->pack();
51: my $Text=$TopRight->Entry(-width=>30)->pack();
52: 
53: my $ResultTextFrame =$MW->Frame(%Border)->pack(-side=>'left');
54: my $ResultTextLabel=$ResultTextFrame->Label(-justify=>'left',-text=>"PreMatch:\nMatch:\nPostMatch:\nResult:\n\$1..n")->pack(%Fill);
55: 
56: my $ResultFrame  =$MW->Frame(%Border)->pack(-side=>'left',%Fill);
57: my $ResultLabel=$ResultFrame->Label(-justify=>'left',-text=>"none\nnone\nnone\nnone")->pack(%Fill);
58: 
59: 
60: $MW->bind('all', '<KeyPress>', \&KeyPress);
61: MainLoop();
62: 
63: sub KeyPress
64: {
65:  local $^W=0;
66:  my $RegEx=$RegExp->get;
67:  my $Text =$Text->get;
68:  my (@Dollar,@Result,$Result,$Match,$PreMatch,$PostMatch);
69:  my $Function;
70:  my $FieldCodes=join "",'$Match=$&;',
71:                         '$PreMatch=$`;',
72:                         "\$PostMatch=\$';",
73:                         "\$Dollar[0]=\$1;",
74:                         "\$Dollar[1]=\$2;",
75:                         "\$Dollar[2]=\$3;",
76:                         "\$Dollar[3]=\$4;",
77:                         "\$Dollar[4]=\$5;";
78:  if (!$AsList)
79:  {
80:   $Function=join "",'($Result=$Text)=~',"$RegEx;",$FieldCodes;
81:  }
82:  else 
83:  {
84:   $Function=join "",'@Result=($Text=~',"$RegEx);",$FieldCodes;
85:  };
86:  eval $Function;
87:  $Result||=join "|",@Result;
88:  $Match||='none'; $PreMatch||='none'; $PostMatch||='none';
89:  $ResultLabel->configure(-text=>"$PreMatch\n$Match\n$PostMatch\n$Result\n@Dollar"); 
90:  $ResultLabel->update;
91: };
92: