[Groff] backspace and Unicode in terminals

[Werner LEMBERG]

I'm going to improve grotty, the TTY backend of groff, so that it can
handle zero-width and double-width characters, as needed for proper
Unicode support.

Doing so I wonder how is the backspace character (U+0008, \b) handled
in TTYs?  Is there any documentation for it?

Most importantly: If I have a wide character at position p which is
followed by `\b' (at position p+2), is the final position p again?
With other words, is the width of `\b' dependent on the width of the
previous character?  What happens if I have a sequence of `\b'
characters?  I'm thinking especially of the interaction at the
beginning of a new line.  Is there a distinction between a user who
presses the `backspace' key, and a `\b' character in the data stream?


    Werner