use strict;
use warnings;
use Data::Dump qw/pp dd/;


use Test::More;

my $wiki =
    '_/one *two*/ th/ree_ null _/f*ur *five*/ six_  null _/se_ven *eight*/ nine_ *fail_';

my $expected =
    '<u><i>one <b>two</b></i> th/ree</u> null <u><i>f*ur <b>five</b></i> six</u>  null <u><i>se_ven <b>eight</b></i> nine</u> *fail_';




my $pre  = qr/(^|\s|>)/;
my $post = qr/($|\s|<)/;
my %h = (
    '*' => 'b' ,
    '/' => 'i' ,
    '_' => 'u' ,
);

    
sub tf { s{ $pre ([_*/]) (.*?) \2 (?=$post)}{$1<$h{$2}>$3</$h{$2}>}xg };

$_=$wiki;

my $DBG = 0;

diag "IN <= '$wiki'\n\n" if $DBG;

for my $i (1..3) {
    tf();
    diag "$i: '$_'\n\n" if $DBG;
}



is($_,$expected,"repeated replace");

my $rec_level=0;

sub rec {
    my ($txt) = @_;

    my $DBG = 1;
    diag ++$rec_level ."< $txt" if $DBG;
    
    $txt =~
     s{
          $pre ([_*/]) (.*?) \2 (?=$post)
     }{
         my $tag = $h{$2}; 
         "$1<$tag>" . rec($3). "</$tag>"
     }xge;
    
    diag $rec_level-- . "> $txt\n" if $DBG;

    return $txt;
}

my $got_rec = rec($wiki);

is($got_rec,$expected,"recursive replace");


done_testing;