In section 6.1, [_] is replaced with [ ] (with the second bracket being italic).

Same thing in 6.2 with tail_len = tail len

Seems like the markdown parser partially went into the code blocks.

Nice! I've been seeing a lot about Erlang lately and have wanted to give it a go. This is perfect. Thanks for posting.

This is also a fantastic resource: http://learnyousomeerlang.com/

Indeed. That's why I referenced it in the second paragraph :)

Also "Stuff Goes Bad: Erlang in Anger" looks quite good.

Also since then Erlang got maps (associative data structure).

Here is a postscript chapter from Learn You Some Erlang on them:

http://learnyousomeerlang.com/maps