Mars lacks readline support

[Matt Giuca]

Mars's interactive mode lacks good command-line editing features, as provided by GNU Readline. This primarily entails a) being able to use command history, edit the current line, etc, and b) being able to do tab-completion and other application-specific things.

A workaround for (a) is to use rlwrap around Mars, but this is tedious since you often forget to use it. There is no workaround for (b) as it requires Mars to perform its own tab completion.

Implement a Mercury binding for GNU Readline, then incorporate it into the Mars interactive shell.

[Matt Giuca (mgiuca)]

Fixed in trunk r898.