On 24/10/2005, at 17.01, Ana Nelson wrote:

I'm having a bit of trouble figuring out how scope is determined by TextMate.

http://macromates.com/blog/archives/2005/07/06/introduction-to-scopes/

What has to happen for "source.ruby.rails" to be active?

You need to switch to “Ruby on Rails” as language. View -> Language -

Rails -> Ruby on Rails.

I am working in documents with .rb and .rhtml extensions

For .rhtml it should identify them as HTML (Rails) (visible in the status bar), but if not, it's View -> Language -> Rails -> HTML (Rails).

but unless I remove the Scope condition I can't get the Rails snippets to be active.

You can btw press ctrl-shift P to view the current scope. For .rb files it is (out-of-the-box) source.ruby. Switching to Ruby on Rails as language makes it source.ruby.rails.