Need for a new system

The current system has a number of flaws.

• It only shows you at most 4 matches, and wastes a lot of horizontal space.
• You can't click on items to choose.
• It's constantly trying to complete, but you may want to see what's underneath it.
• There is no way to have it use more space for when you do want that.

Completion2 mockups

Initially, completions will be a single line multi-column display. This will make them relatively unobtrusive. You know how many there are, but don't see a big list. You can continue to refine the list by typing. It will update on a timeout (we might want to have a status message for when the completions are stale).

Now, when you hit TAB - if there is only one completion, we choose it. If all completions have a common prefix, we fill in with that, and recomplete. This matches bash. If there are ambiguous completions, TAB expands the display:

See also issue 14. We need a canvas/table layout for this.

Should completions be case-insensitive? See issue 61.

Thoughts on code changes

Completion objects

Completions match the start of input tokens.

class Completion(object):
  token, info, icon

The token represents what we have to add to the current input to get a valid completion. It is unique among a set of returned completions - this differs from the current system which will return both the ls builtin and /bin/ls for "ls". info is an arbitrary string describing additional data (for example, it might be "Builtin" for a builtin, or "/usr/bin/foo" for a system executable completion, or "python -c ..." for a process ID completion).

Now, we need to rewrite the current hotwire/completion.py classes to generate these types of completions. This should be a fairly large simplification.

Rework keyboard handling + display

Try to move things out of shell.py if we can into ui/completion.py. Generally follow mockups above.