I wrote for tcsh(1) three years ago.
- implement EL_RPROMPT, which allows a setting/getting of a function which
returns a string to be used as the right-side prompt.
- improve HISTORY and AUTHORS sections in editline(3).
- bump shlib minor version for EL_RPROMPT.
XXX: due to an implementation issue, the rprompt has a 1 space gap before the
edge of the logical screen. editline's logical screen is 1 space less
than the full screen width, so there's a 2 space gap between the rprompt
and the right end of the physical screen. i'm not concerned about this.
re_refresh(): cast the character passed to re_addc() to unsigned char,
so we don't end up calling isprint() with negative value
when chars are signed and character value is >= 128
