As of jade 1.0 there’s an easier way to deal with this, unfortunately I can’t find it anywhere in the official documentation.
You can add inline elements with the following syntax:
#[a.someClass A Link!]
So, an example without going into multiple lines in a p, would be something like:
p: #[span this is the start of the para] #[a(href="http://example.com") a link] #[span and this is the rest of the paragraph]
You can also do nested inline elements:
p: This is a #[a(href="#") link with a nested #[span element]]