[node-dev] while readline.prompt(),input multi-byte character，press del or backspace key,cursor position was wrong

[rongsheng gu]

i call function readline.prompt(),
then input multi-byte character (such as Chinese character) on screen，
press del or backspace key,cursor  position was wrong.

I found this on osx lion 10.7.4, centos 5.5 with node v0.6.18