Hi,
I'm trying textmate. How best to be introduced to this editor? Is there a tutorial anywhere -- especially a rails specific one?
I don't intend to sound condescending, but you should try to at least look over the manual. Some sections that will be immediately helpful are:
* Working with Text [1] * Bundles [2]
The screencasts are real helpful too. http://macromates.com/screencasts
etc. What key sequences are doing this expansion?
The Tab key.
The "magical" expansions that you'll run across in the screencasts and what not are either "Snippets" or "Macros". Keep yours eyes open for those words as are you're perusing the manual and it should become a bit clearer.
HTH -steve
[1] http://macromates.com/textmate/manual/ working_with_text#working_with_text [2] http://macromates.com/textmate/manual/bundles#bundles