AsciiDoc source code block shorthand

In AsciiDoc, you normally make a source code block by adding the source style and a language to a listing (or literal) block.

[source, ruby]
----
puts "Hello, World!"

[1, [2, 3], 4].flatten.size == 4
----

You need at least four hyphens (e.g., ----) around the content to create a listing block. But it's possible to get away with less by using an open block!

An open block is a special block that can masquerade as most other delimited blocks. It's created by fencing the content with lines that consist of exactly two hyphens (e.g., --).

In order to turn an open block into another block, you need to specify the block style (e.g., source) in the attribute list above the block. Since we're doing that already to create our source code block, it means we can save a total of four hyphen characters (two on either side of the block).

[source, ruby]
--
puts "Hello, World!"

[1, [2, 3], 4].flatten.size == 4
--

Why would you ever type four hyphens around the content to create a source code block in AsciiDoc when you can just as well use two? Less is more :)