Why scalamd not escape charactors in code blocks?

[freewind]

For example, I write a code block in markdown:

& + < + &rt;

This line starts with 4 spaces, so it's a code block.

I use a javascript port of markdown, it will convert it to:

& + < + &rt;

So, it displays correct.

But scalamd won't escape them, so we can only see the follow in the page:

& + < + >

Since they are in <pre><code></code></pre>, I think they should be converted automaticlly.