e() method is called with the
concatenated contents of the buffer as source.  If this
indicates that the command was executed or invalid, the buffer
is reset; otherwise, the command is incomplete, and the buffer
is left as it was after the line was appended.  The return
value is 1 if more input is required, 0 if the line was dealt
with in some way (this is the same as runsource()).

rj