Alchemy Markdown

Topics:

It's time to learn how to use mix! Mix is the Elixir equivalent of npm/yarn, pip or gem and it plays a fundamental role in dependency management, automated testing, OTP application management and scripting.

Last episode we worked on a minimal (and incomplete) implementation of Markdown. Now we're going to use mix to pull in Earmark, a Markdown implementation. Interestingly, its author is Dave Thomas, who wrote the excellent guide Programming Elixir.

Here's a breakdown of this episode:

Choosing Earmark - (1:44)
Getting started with mix - (3:10)
A first look at testing - (5:37)
The mix file and adding deps - (8:47)
Using Earmark and adding functionality & unit tests - (12:00)
Reviewing unit tests and migrating integration test from last time - (31:07)
Discovering Earmark is a dash-eater (plus workaround) - (37:30)

The markdown features implemented are:

All the standard ones implemented by Earmark (thank you Dave and thank you Mix!)
<big></big> tags, by placing ++ before and after a string of text.
 tags by placing -- before and after a string of text.
<hr/> tags by making a line start with three or more - or * characters with any number of spaces between them.

All of these features as well as those from MiniMarkdown are unit tested using the standard mix test.

3 Comments

If you use three ` in a row, you can do GFM-style comments here!

- alchemist · 5 years ago

My -- turns into ΓÇô on windows powershell. I tried <<45>> with no luck. So my tests fail with left: "\nSome ΓÇôsmallΓÇô words!\n" right: "small words"

When I use git bash I get: left: "\nSome –small– words!\n" right: "small words"

- jifem · 5 years ago

Another way to regex for hrs :

def hrs(text) do
    Regex.replace(~r/(\r\n|\r|\n|^)([*-])\s*(\2\s*){2,}/, text, "\\1<hr />")
end

- jtoulouse · 5 years ago