skipping duplicates in some zle functions

[Dominik Vogt <dominik.vogt@gmx.de>]

I'm already using a fairly complicated function bound to Up and
Down that combines up/down-line-or-search and
history-beginning-search-forward/backward (see below).

I want to enhance it so that it skips lines that are identical
to the line that is currently displayed.  E.g. If I have the
following lines in the history (latest one at the bottom):

  ls /tmp
  cd /tmp
  ls foo*
  rm foo
  rm foobar
  ls foo*
  cd

Now I type

  $ ls f<crsr-up>
        ^
        |___ cursor

and get

  $ ls foo*
        ^
        |___ cursor

Now I press <crsr-up> again, and with the current functions, the
second "ls foo*" entry is selected.  But I'd rather skip that one
and proceed to "ls /tmp" immediately.

Any hints how to do this?

------------------------------- snip ----------------------------
function __up_or_down_line_or_beginning_search {
if [[ $LASTWIDGET != down-line-or-beginning-search &&
      $LASTWIDGET != up-line-or-beginning-search ]]; then
    local LBUFFER_STRIPPED="${LBUFFER/#[       ]#/}"
    if [[ $RBUFFER == *$'\n'* ||
          ${LBUFFER_STRIPPED} == "" ]]; then
        __last_up_line=up-line-or-history
        __last_down_line=down-line-or-history
    else
        LBUFFER_STRIPPED="${LBUFFER_STRIPPED/#[^   ]#[   ]#/}"
        if [[ "$LBUFFER_STRIPPED" == "" ]]; then
            __last_up_line=up-line-or-search
            __last_down_line=down-line-or-search
        else
            __last_up_line=history-beginning-search-backward
            __last_down_line=history-beginning-search-forward
        fi
    fi
fi
}
zle -N __up_or_down_line_or_beginning_search

function up-line-or-beginning-search {
    __up_or_down_line_or_beginning_search
    zle .${__last_up_line:-beep}
}
zle -N up-line-or-beginning-search

function down-line-or-beginning-search {
    __up_or_down_line_or_beginning_search
    zle .${__last_down_line:-beep}
}
zle -N down-line-or-beginning-search

bindkey "\e[A" up-line-or-beginning-search   # Cursor up
bindkey "\e[B" down-line-or-beginning-search # Cursor down
------------------------------- snip ----------------------------

Ciao

Dominik ^_^  ^_^