Nested classes dont compile

[Meduzz]

Im so glad you've decided to make a pure pug template parser/compiler/thingie! Amber's been a solid goto, to fill this void (for Go) for a while, but it's not pure pug.

Unfortunately I've ran into a little snag. Basically I have 2 templates:

layout.pug

doctype html
html
    head
        title Title
        block head
    body
        block content

and index.pug

extend layout

block content
    .columns
        .column
            h1 Left
        .column
            h1 Right

When I try to compile index.pug, I get this error:

Error #01: parse error: templates/index.pug, [line 5, col 0]: interface conversion: interface {} is nil, not string

So it seems it handles the first class, but not the second.

If I prefix classes with div it works like a charm though, so there's an easy work around for now.