Multiple improvements to tab completion....
Multiple improvements to tab completion.
I refactored the API quite a bit, to retain readline compatibility but
make it more independent of readline. There's still more to do in
cleaning up our init_readline() method, but now the completer objects
have separate rlcomplete() and complete() methods. The former uses
the quirky readline API with a state flag, while the latter is
stateless, takes only text information, and is more suitable for GUIs
and other frontends to call programatically.
Made other minor fixes to ensure the test suite passes in full.
While all this code is a bit messy, we're getting in the direction of
the APIs we need in the long run.
