[test #22](http://lol.asd)
->
[url=http://lol.asd]test [project]22[/url[/project]]
I'd expect it would be [url=http://lol.asd]test #22[/url]: the # and the @ inside the "title" of an url should not be parsed.

When headings are parsed, an id attribute is set for the heading tag. The id value is the same as the text within the tag.

# Heading 1    -> <h1 id="heading1">Heading 1</h1>
### Heading 3  -> <h3 id="heading3">Heading 3</h3>

Heading 1
=========  -> <h1 id="heading1">Heading 1</h1>

Heading 2
---------  -> <h2 id="heading2">Heading 2</h2>

This behavior may cause conflicts if the new id generated matches an id already existing and in use, resulting in the website not working properly.

as seen on https://www.nerdz.eu/Nerdz:198

Deprecated

[youtube]http://www.youtube.com/watch?v=_ynuMmB91qM[/youtube]
[yt]http://www.youtube.com/watch?v=_ynuMmB91qM[/yt]

These tags will be dropped.

New tags

[video]http://www.youtube.com/watch?v=XXXXXXXXXXX[/video] { it works on dailymotion.com - vimeo.com - facebook.com }
[twitter] https://twitter.com/PTKDev/status/290091113484808192 [/twitter] { even 290091113484808192 (the Tweet ID) is enough }
[spotify] track:artist:< id > [/spotify] { more on https://developer.spotify.com/technologies/widgets/spotify-play-button/ - or https://play.spotify.com/track/< id > }

It's not a bug, just a matter of appearance.
While empty lines in Markdown are used with the sole purpose of dividing "blocks", during the conversion from BBCode to HTML each new line feed in BBCode is converted into a new line HTML tag (<br/>). This means that blocks like quotes which usually have already a bottom margin of their own will see this margin increased (and there's no way at the moment to avoid this since you need to leave a line empty for a block to be recognized by the parser).

```perl
use Data::Dumper;
print '@lol';
print "#md2bbc";
print "~~deleted~~";
print Dumper($val);
print "do you wanna use `lol` ?"; 
\```

in md2bbc, this snippet generates

[code=perl]
use Data::Dumper;
print '[lol](https://nerdz.eu/lol.)';
print "[md2bbc](https://nerdz.eu/md2bbc:)";
print "[del]deleted[/del]";
print Dumper($val);
print "do you wanna use [code]lol[/code] ?"; 
[/code]

This means that extensions applied before the parsing are (incorrectly, in this case) applied into the code sections. The single backtick (that's not an extension) is incorrectly parsed too.

The syntax reference on code tags specifies

Regular Markdown syntax is not processed within code blocks. E.g., asterisks are just literal asterisks within a code block. This means it’s also easy to use Markdown to write about Markdown’s own syntax.

https://www.nerdz.eu/md2bbc-a-zilla:3

! is a good idea tho.

[code=md]
![](http://google.com/save_it_bro.pl)
<http://google.com/save_it_bro.pl>
[/code]

\```md
![](http://google.com/save_it_bro.pl)
<http://google.com/save_it_bro.pl>
\```

is parsed to

[code=md]
[img]http://google.com/save_it_bro.pl[/img]
[url]http://google.com/save_it_bro.pl[/url]
[/code]
[code=md]
![](http://google.com/save_it_bro.pl)
<http://google.com/save_it_bro.pl>
[/code]

Probably, other "special" tags (e.g. [url]) are not recognized.
We don't have any test regarding these bbc/md mixes

When quoting text using '>' at the beginning of each line, make the empty line optional.

Usually, you need to leave an empty line after the last line you quoted, like this:

> quoted text
> quoted text

not quoted text

Make that empty line optional, so that it works even like this:

> quoted text
> quoted text
not quoted text

The main reason is that when people quote multiple lines like this, they highlight each quoted line with '>' at the beginning, so it's already clear what has to be included in the quote bbcode and what has not to be included.
It's also the way some people (including me) are used to, and everybody knows that habits die hard (<3).

I noticed that test for 4-spaced code markdown are not present.
An example of 4-spaced code is

before code

    my $lol = 5
    print "topkek" x $lol

after code

Please confirm that this input string:

[quote=1234|u]:(

Breaks Showdown#makeBBCode and returns an empty string.