Completion functions

[jpaugh]

repla desperately needs completion functions! Here are two ways to go about this but I don't like either of them, so any suggestions are welcome.

Define completion functions in Python (or Pythonic way), and use them.

Pros:

• Builtins and wrapped commands use same completion format/infrastructure
• Easy to do: just make a completion framework, then add a few custom handlers
• More can be added by users.
• Can be built into shell language--or just use Python

  Cons:

• Duplicating effort: package maintainers already have to deal separately with completion for bash and zsh, for example.

  Run the user's preferred shell in a pseudo-tty and call its completion functions.

  Pros:

• All around, less work.
• Don't need custom completion functions for any commands (except builtins)
• User chooses their preferred completion mechanism (by virtue of choosing their shell)

  Cons:

• User's shell might not support completion
• Have do deal with quirks of each shell.
• Redundant shell. Yikes!
• All around, more work: have to figure out how master/slave ptys work.

[jpaugh]

Idk.