I really don’t need the overhead of Rails for my very small project, so I’m trying to achieve this just using just plain Ruby and HAML.
I want to include another HAM
I've had great success just using the instructions posted by David Richards in a concatenated way, without variables, like this:
= Haml::Engine.new(File.read('/Volumes/Project/file_to_include.haml')).render
There's obviously a more elegant way. But for someone who just wants to include one or two files, this should work nicely. It's a drawback that all base files using these includes have to be recompiled after some changes to the latter. It might be worthwile to just use php include if the environment allows that.