Syntax highlighting does not work with fenced (~~~) code blocks

[sol]

If I use something like

~~~ {.haskell}
main :: IO ()
main = putStrLn "hello, world!"
~~~

I would like to get syntax highlighting for Haskell code.

My motivation to use this over

```haskell
...
```

is that it is compatible with other software, and it allows me to add several classes to a single code block (e.g. ~~~ {.haskell .literate}).

BTW: GFM and GitHub's README renderer do the right thing here.

[ghost]

We have a lot of code in ```bash blocks that stopped working as of 2.2.2. Same issue or new issue?

[bootstraponline]

Same issue. pygments.rb was upgraded which handles syntax highlighting. I will look into why it's not working as expected. The existing code highlighting unit tests all pass so test coverage has to improve.

[bootstraponline]

@riddley The following is syntax highlighted when I save the page. Does it work for you?

```bash
'test'
````

It doesn't appear highlighted in live preview though. I fixed bash highlighting for live preview on master. It'll be in the next release.

[bootstraponline]

@sol Gollum has never supported the ~~~ syntax. I agree this would be a great feature though.

[bootstraponline]

@sol Is the ~~~ syntax detailed somewhere? I added support for single languages ~~~ {.ruby} but multiple languages such as ~~~ {.haskell .literate} will fail. The references I've found only show one language per block.

[sol]

@bootstraponline I don't think so. But you can look at e.g. Pandoc's Users Guide.

What about just ignoring all but the first class name? I think that is what GFM does. The thing why I want more classes is that I want to extract code pieces to test/verify them. So I may have things like ~~~ {.haskell .example-1}.

[bootstraponline]

@sol Thanks for the link. I'll update the code to use just the first class name and ignore everything else.

[bootstraponline]

Gollum 2.2.4 has been released on RubyGems and includes this feature. Let me know if it works as expected.

[sol]

@bootstraponline It works already pretty well. Thanks for that!

"Fences" of arbitrary length do not work yet. They are useful, if you want to write a code block that itself contains markdown, e.g.:

Gollum supports fenced code blocks.  Here is an example:
~~~~~~ .markdown
~~~ .ruby
puts 'Hello world'
~~~
~~~~~~

The relevant parts of Pandoc's User's Guide (emphasis added):

These begin with a row of three or more tildes (~) or backticks (`) and end with a row of tildes or backticks that must be at least as long as the starting row. Everything between these lines is treated as code.

...

If the code itself contains a row of tildes or backticks, just use a longer row of tildes or backticks at the start and end.

In addition, the live preview does not handle it correctly, yet.

Both issues are not very critical for me. I think arbitrary length delimiters are a good idea. I don't care at all about the live preview.

And thanks again for implementing it in the first place, it already solves my use case :)

[bootstraponline]

Thanks for pointing out the details for tilde fenced code blocks. I will look into implementing arbitrary length tilde fences for Gollum.

I opened #546 about better support in live preview. I don't think that's worth fixing in live preview unless someone plans on using it because the ``` syntax always works correctly.

@sol This doesn't work for you in live preview? It works for me. There are other examples which break though.

~~~~ {.ruby}
~~
'hi'
~~
~~~~

[sol]

@bootstraponline Yes, this simple example works. I just realized that the actual parser is now more permissive than what is used for live preview. But I don't think it's a big issue.

[bootstraponline]

The parser is the same, both use sundown. The extraction code is a bit different now that ~~~ is supported. I released 2.2.5. Let me know if it works as expected.

[ghost]

Perhaps I should have reported it separately, but as of 2.2.9 ```bash blocks still don't work like they did with 2.2.1.

[bootstraponline]

@riddley I opened #550. Please provide a reproducible example so I can fix the issue.