#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11112988
use warnings;

my $wiki =
    '_/one *two*/ th/ree_ null _/four *five*/ six_  null _/se_ven *eig
+ht*/ nine_';

my $expected =
    '<u><i>one <b>two</b></i> th/ree</u> null <u><i>four <b>five</b></
+i> six</u>  null <u><i>se_ven <b>eight</b></i> nine</u>'; 

my %h = (
    '*' => 'b' ,
    '/' => 'i' ,
    '_' => 'u' ,
);

my $html = $wiki =~ s{ (?:^|\s) \K ([*_/]+) | ([*_/]*) (?=$|\s) }
  { $1 ? $1 =~ s|.|<$h{$&}>|gr : $2 =~ s|.|</$h{$&}>|gr }gexr;

print $html eq $expected ? "passed" : "FAILED", "\n\n";
print $wiki, "\n\n", $expected, "\n\n", $html, "\n";
[download]

Outputs;

passed

_/one *two*/ th/ree_ null _/four *five*/ six_  null _/se_ven *eight*/ 
+nine_

<u><i>one <b>two</b></i> th/ree</u> null <u><i>four <b>five</b></i> si
+x</u>  null <u><i>se_ven <b>eight</b></i> nine</u>

<u><i>one <b>two</b></i> th/ree</u> null <u><i>four <b>five</b></i> si
+x</u>  null <u><i>se_ven <b>eight</b></i> nine</u>
[download]

ah yes \K not \G I keep confusing them.

And I thought that $1 and $2 are read-only ... ah I see you use the /r flag.

anyway, markup should be paired.°

my $wiki =
    '_one*';

my $expected = $wiki;


$html = $wiki =~ s{ (?:^|\s) \K ([*_/]+) | ([*_/]*) (?=$|\s) }
  { $1 ? $1 =~ s|.|<$h{$&}>|gr : $2 =~ s|.|</$h{$&}>|gr }gexr;

print $html eq $expected ? "passed" : "FAILED", "\n\n";
print $wiki, "\n\n", $expected, "\n\n", $html, "\n";
[download]

FAILED

_one*

_one*

<u>one</b>
[download]

I've updated the tests in Re: wiki regex reprocessing replacement (UPDATED^2) with markup to ignore

Funny enough, the monastery fails too :)

FAILED

_one*

_one*

one  

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery}

°) yes I know, wasn't explicitely tested

Let it fail, it should be obvious in the preview.

hehehe

Here's my take. One thing I don't understand is the inclusion of  > < characters in the pre- and post-markup tag delimiters (update: e.g.,  my $pre  = qr/(^|\s|>)/; here), probably because I'm not familiar with wikisyntax. Can you link me to a discussion of the role of these characters? I prepared two versions, one using  (?(DEFINE) ...) and one based purely on  qr// interpolation. Maybe one is faster, but I haven't done any Benchmark-ing (nor am I likely to).

Wow, thanks :)

And the test suite ++

> One thing I don't understand is the inclusion of > < characters in the pre- and post-markup tag delimiters

Because the repetitive solution with tf() needs to ignore previous runs.

*/_word_/* -> <b>/_word_/</b> -> <b><i>_word_</i></b> -> etc.

The recursive solution with rec() doesn't really need it, one of the reasons why I prefer this approach.

> probably because I'm not familiar with wikisyntax.

No you are not wrong, there was information missing.

In this particular case the syntax is also meant to coexist with more verbose html tags.

There are cases where one doesn't want to have a whitespace in between neighboring tags.

Just compare Re^3: Good Intentions: Wikisyntax for the Monastery and the complaint about 'ARGV'<br> not expanding.

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery}

You're welcome.

Here are some test cases I've added since posting. I'd be very interested to hear your comments, especially as regards the "questionable" ones.

  '--- tests added 16feb20 after pm#11113014 post ---',

  '"failing" (i.e., no transformation) tests',
  [ ''           => '',           ],
  [ '*'          => '*',          ],
  [ '*_/'        => '*_/',        ],
  [ ' * _ / '    => ' * _ / ',    ],
  [ '*fail/'     => '*fail/',     ],
  [ ' * fail / ' => ' * fail / ', ],

  'possibly questionable transformations',
  [  '__'            =>  '<u></u>',                             ],
  [ ' __ '           => ' <u></u> ',                            ],
  [  '__ __'         =>  '<u></u> <u></u>',                     ],
  [ ' __ __ '        => ' <u></u> <u></u> ',                    ],
  [  '____'          =>  '<u></u><u></u>',                '???' ],
  [ ' ____ '         => ' <u></u><u></u> ',               '???' ],
  [  '______'        =>  '<u></u><u></u><u></u>',         '???' ],
  [ ' ______ '       => ' <u></u><u></u><u></u> ',        '???' ],
  [   '________'     =>  '<u></u><u></u><u></u><u></u>',  '???' ],
  [  ' ________ '    => ' <u></u><u></u><u></u><u></u> ', '???' ],
  [   '__ __ __ __'  =>  '<u></u> <u></u> <u></u> <u></u>',     ],
  [  ' __ __ __ __ ' => ' <u></u> <u></u> <u></u> <u></u> ',    ],
[download]

In this particular case the syntax is also meant to coexist with more verbose html tags.
There are cases where one doesn't want to have a whitespace in between neighboring tags.

Can you supply some test cases for variations, especially WRT intermixtures with standard HTML?

---

Give a man a fish:  <%-{-{-{-<

here we go

(update: please see Re: wiki regex reprocessing replacement (UPDATED^2) for better testcases including wrong markup)

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


use Test::More;

my $wiki =
    '_/one *two*/ three_ null _/four *five*/ six_  null _/seven *eight
+*/ nine_';

my $expected =
    '<u><i>one <b>two</b></i> three</u> null <u><i>four <b>five</b></i
+> six</u>  null <u><i>seven <b>eight</b></i> nine</u>';



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 = 1;

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

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



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

done_testing;
[download]

# IN <= '_/one *two*/ three_ null _/four *five*/ six_  null _/seven *e
+ight*/ nine_'
# 
# 1: '<u>/one *two*/ three</u> null <u>/four *five*/ six</u>  null <u>
+/seven *eight*/ nine</u>'
# 
# 2: '<u><i>one *two*</i> three</u> null <u><i>four *five*</i> six</u>
+  null <u><i>seven *eight*</i> nine</u>'
# 
# 3: '<u><i>one <b>two</b></i> three</u> null <u><i>four <b>five</b></
+i> six</u>  null <u><i>seven <b>eight</b></i> nine</u>'
# 
ok 1 -  repeated replace works
1..1
[download]

# IN <= '_/one *two*/ three_ null _/four *five*/ six_  null _/seven *eight*/ nine_'
# 
# 1: '/one *two*/ three null /four *five*/ six  null /seven *eight*/ nine'
# 
# 2: 'one *two* three null four *five* six  null seven *eight* nine'
# 
# 3: 'one two three null four five six  null seven eight nine'
# 
ok 1 -  repeated replace works
1..1

Here's a non-recursive way which I think fits your criteria:

use strict;
use warnings;
use Test::More;

my $wiki =
    '_/one *two*/ three_ null _/four *five*/ six_  null _/seven *eight
+*/ nine_';

my $expected =
    '<u><i>one <b>two</b></i> three</u> null <u><i>four <b>five</b></i
+> six</u>  null <u><i>seven <b>eight</b></i> nine</u>';

my %h = (
    '*' => 'b' ,
    '/' => 'i' ,
    '_' => 'u' ,
);

my $DBG = 1;

sub flip {
    my $s = shift;
    my $z = $h{$s};
    $h{$s} = $z =~ /\// ? substr ($z, 1, 1) : "/$z";
    return "<$z>";
}

sub tf {
    diag "Pre: '$_'\n\n" if $DBG;
    s{([_*/])}{flip($1)}eg
};

$_ = $wiki;
diag "IN <= '$wiki'\n\n" if $DBG;
tf();

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

done_testing;
[download]

Many thanks, :)

... but ...

The testsuite should have also included markup which must not be replaced

My fault sorry, I thought it's obvious by the $pre and $post regex.

The markup must come in pairs and be embraced by special word boundaries.

(whitespace or other markup or tag-brackets or ... depending on pre/post)

Hence a _ inside a word is forbidden, which makes sense for joined_identifiers .

I've updated the tests in Re: wiki regex reprocessing replacement (UPDATED^2) with markup to ignore

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery}

Expanded test case with wrong markup to be ignored

• markup inside word
• wrong pairs like *fail_

> to call tf() recursively in the /e evaled replacement part

seems to work well, see sub rec

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 *eig
+ht*/ 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;
[download]

ok 1 - repeated replace
# 1< _/one *two*/ th/ree_ null _/f*ur *five*/ six_  null _/se_ven *eight*/ nine_ *fail_
# 2< /one *two*/ th/ree
# 3< one *two*
# 4< two
# 4> two
# 3> one two
# 2> one two th/ree
# 2< /f*ur *five*/ six
# 3< f*ur *five*
# 4< five
# 4> five
# 3> f*ur five
# 2> f*ur five six
# 2< /se_ven *eight*/ nine
# 3< se_ven *eight*
# 4< eight
# 4> eight
# 3> se_ven eight
# 2> se_ven eight nine
# 1> one two th/ree null f*ur five six  null se_ven eight nine *fail_
ok 2 - recursive replace
1..2