Instant response to readline-ish line editing

Mosh currently provides instant response to basic line editing: Typing and moving the cursor using the arrow keys. This feature is a great productivity-enhancer on high-latency links.

However, as soon as some more advanced line-editing is attempted, the predictive model gives up, and Mosh will wait for the server response before regaining the instant responsiveness.

Examples of commonly used line-editing that is not supported include:

• moving the cursor backwards by a whole word (using meta+b)
• erasing a whole word backwards (using meta+backspace)
• transposing characters or words (using ctrl+t and meta+t)

This is all readline-ish behaviour. Granted, not all programs are readline-based. Yet, it seems to be a fairly safe assumption that readline-ish behaviour is expected when any of the keystrokes given above are detected.

Wouldn't it be neat if mosh employed readline locally to guess the outcome of these line-editing operations?

Start by tracing mosh's predictive model for the existing instant arrow-key editing, then examine how readline-style operations are represented. Done means commonly used word movement, word deletion, and character or word transposition are predicted locally without waiting for the server.