This is a nice way to map it out and preserve the spatial relationships of the text. Tabs are changed to ' -> ' and spaces to dots '·' (chr 183 ASCII). This is how my editor displays them when I select the display all chars option. chr 182 ASCII is that funny backwards P symbol ¶ used for newlines. We use the octal naming convention for these chars for convenience. chr 0266 = '¶' and chr 0267 = '·'

In the unlikely event these special chars are included in the text to be processed we hex encode them using the standard URL encoding convention of a % followed by two hex digits. We can then remove the URL encoding to regenerate our original text.

sub show {
    my @data = @_;
    for (@data) {
        s/(\266|\267)/sprintf"%%%02X",ord $1/egm;
        s/ /chr(0267)/egm;
        s/\t/ -> /gm;
        s/\n/chr(0266)."\n"/egm;
    }
  return wantarray ? @data : join'',@data;
}

sub hide {
    my @data = @_;
    for (@data) {
        s/ -> /\t/gm;
        s/\266//gm;
        s/\267/ /gm;
        s/%([0-9a-f][0-9a-f])/chr hex $1/eigm;
    }
  return wantarray ? @data : join'',@data;
}

@data = (<DATA>)[0..7];

print "Original data, including specials\n\n";
print @data;

print "\n\nShow invisible chars in data\n\n";
print show(@data);

print "\n\nHide and show data - should not change\n\n";
print hide(show(@data));

__DATA__
    tab
    4 spaces, trailing tab    
        tab and 4 spaces
        
····4·spaces,·trailing·tab -> ¶
 -> ····tab·and·4·spaces¶
 ->  -> ¶
¶
[download]

cheers

tachyon

s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print