add zsh

1 files changed, 759 insertions, 0 deletions

diff --git a/oh-my-zsh/plugins/history-substring-search/history-substring-search.zsh b/oh-my-zsh/plugins/history-substring-search/history-substring-search.zsh
new file mode 100644
index 0000000..c326778
--- /dev/null
+++ b/oh-my-zsh/plugins/history-substring-search/history-substring-search.zsh
@@ -0,0 +1,759 @@
+#!/usr/bin/env zsh
+##############################################################################
+#
+# Copyright (c) 2009 Peter Stephenson
+# Copyright (c) 2011 Guido van Steen
+# Copyright (c) 2011 Suraj N. Kurapati
+# Copyright (c) 2011 Sorin Ionescu
+# Copyright (c) 2011 Vincent Guerci
+# Copyright (c) 2016 Geza Lore
+# Copyright (c) 2017 Bengt Brodersen
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+#  * Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+#
+#  * Redistributions in binary form must reproduce the above
+#    copyright notice, this list of conditions and the following
+#    disclaimer in the documentation and/or other materials provided
+#    with the distribution.
+#
+#  * Neither the name of the FIZSH nor the names of its contributors
+#    may be used to endorse or promote products derived from this
+#    software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+##############################################################################
+
+#-----------------------------------------------------------------------------
+# declare global configuration variables
+#-----------------------------------------------------------------------------
+
+typeset -g HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_FOUND='bg=magenta,fg=white,bold'
+typeset -g HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_NOT_FOUND='bg=red,fg=white,bold'
+typeset -g HISTORY_SUBSTRING_SEARCH_GLOBBING_FLAGS='i'
+typeset -g HISTORY_SUBSTRING_SEARCH_ENSURE_UNIQUE=''
+typeset -g HISTORY_SUBSTRING_SEARCH_FUZZY=''
+
+#-----------------------------------------------------------------------------
+# declare internal global variables
+#-----------------------------------------------------------------------------
+
+typeset -g BUFFER MATCH MBEGIN MEND CURSOR
+typeset -g _history_substring_search_refresh_display
+typeset -g _history_substring_search_query_highlight
+typeset -g _history_substring_search_result
+typeset -g _history_substring_search_query
+typeset -g -a _history_substring_search_query_parts
+typeset -g -a _history_substring_search_raw_matches
+typeset -g -i _history_substring_search_raw_match_index
+typeset -g -a _history_substring_search_matches
+typeset -g -i _history_substring_search_match_index
+typeset -g -A _history_substring_search_unique_filter
+
+#-----------------------------------------------------------------------------
+# the main ZLE widgets
+#-----------------------------------------------------------------------------
+
+history-substring-search-up() {
+  _history-substring-search-begin
+
+  _history-substring-search-up-history ||
+  _history-substring-search-up-buffer ||
+  _history-substring-search-up-search
+
+  _history-substring-search-end
+}
+
+history-substring-search-down() {
+  _history-substring-search-begin
+
+  _history-substring-search-down-history ||
+  _history-substring-search-down-buffer ||
+  _history-substring-search-down-search
+
+  _history-substring-search-end
+}
+
+zle -N history-substring-search-up
+zle -N history-substring-search-down
+
+#-----------------------------------------------------------------------------
+# implementation details
+#-----------------------------------------------------------------------------
+
+zmodload -F zsh/parameter
+
+#
+# We have to "override" some keys and widgets if the
+# zsh-syntax-highlighting plugin has not been loaded:
+#
+# https://github.com/nicoulaj/zsh-syntax-highlighting
+#
+if [[ $+functions[_zsh_highlight] -eq 0 ]]; then
+  #
+  # Dummy implementation of _zsh_highlight() that
+  # simply removes any existing highlights when the
+  # user inserts printable characters into $BUFFER.
+  #
+  _zsh_highlight() {
+    if [[ $KEYS == [[:print:]] ]]; then
+      region_highlight=()
+    fi
+  }
+
+  #
+  # The following snippet was taken from the zsh-syntax-highlighting project:
+  #
+  # https://github.com/zsh-users/zsh-syntax-highlighting/blob/56b134f5d62ae3d4e66c7f52bd0cc2595f9b305b/zsh-syntax-highlighting.zsh#L126-161
+  #
+  # Copyright (c) 2010-2011 zsh-syntax-highlighting contributors
+  # All rights reserved.
+  #
+  # Redistribution and use in source and binary forms, with or without
+  # modification, are permitted provided that the following conditions are
+  # met:
+  #
+  #  * Redistributions of source code must retain the above copyright
+  #    notice, this list of conditions and the following disclaimer.
+  #
+  #  * Redistributions in binary form must reproduce the above copyright
+  #    notice, this list of conditions and the following disclaimer in the
+  #    documentation and/or other materials provided with the distribution.
+  #
+  #  * Neither the name of the zsh-syntax-highlighting contributors nor the
+  #    names of its contributors may be used to endorse or promote products
+  #    derived from this software without specific prior written permission.
+  #
+  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+  # IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+  # THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+  # PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+  # CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+  # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+  # PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+  # PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+  # LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+  # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+  # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+  #
+  #--------------8<-------------------8<-------------------8<-----------------
+  # Rebind all ZLE widgets to make them invoke _zsh_highlights.
+  _zsh_highlight_bind_widgets()
+  {
+    # Load ZSH module zsh/zleparameter, needed to override user defined widgets.
+    zmodload zsh/zleparameter 2>/dev/null || {
+      echo 'zsh-syntax-highlighting: failed loading zsh/zleparameter.' >&2
+      return 1
+    }
+
+    # Override ZLE widgets to make them invoke _zsh_highlight.
+    local cur_widget
+    for cur_widget in ${${(f)"$(builtin zle -la)"}:#(.*|_*|orig-*|run-help|which-command|beep|yank*)}; do
+      case $widgets[$cur_widget] in
+
+        # Already rebound event: do nothing.
+        user:$cur_widget|user:_zsh_highlight_widget_*);;
+
+        # User defined widget: override and rebind old one with prefix "orig-".
+        user:*) eval "zle -N orig-$cur_widget ${widgets[$cur_widget]#*:}; \
+                      _zsh_highlight_widget_$cur_widget() { builtin zle orig-$cur_widget -- \"\$@\" && _zsh_highlight }; \
+                      zle -N $cur_widget _zsh_highlight_widget_$cur_widget";;
+
+        # Completion widget: override and rebind old one with prefix "orig-".
+        completion:*) eval "zle -C orig-$cur_widget ${${widgets[$cur_widget]#*:}/:/ }; \
+                            _zsh_highlight_widget_$cur_widget() { builtin zle orig-$cur_widget -- \"\$@\" && _zsh_highlight }; \
+                            zle -N $cur_widget _zsh_highlight_widget_$cur_widget";;
+
+        # Builtin widget: override and make it call the builtin ".widget".
+        builtin) eval "_zsh_highlight_widget_$cur_widget() { builtin zle .$cur_widget -- \"\$@\" && _zsh_highlight }; \
+                       zle -N $cur_widget _zsh_highlight_widget_$cur_widget";;
+
+        # Default: unhandled case.
+        *) echo "zsh-syntax-highlighting: unhandled ZLE widget '$cur_widget'" >&2 ;;
+      esac
+    done
+  }
+  #-------------->8------------------->8------------------->8-----------------
+
+  _zsh_highlight_bind_widgets
+fi
+
+_history-substring-search-begin() {
+  setopt localoptions extendedglob
+
+  _history_substring_search_refresh_display=
+  _history_substring_search_query_highlight=
+
+  #
+  # If the buffer is the same as the previously displayed history substring
+  # search result, then just keep stepping through the match list. Otherwise
+  # start a new search.
+  #
+  if [[ -n $BUFFER && $BUFFER == ${_history_substring_search_result:-} ]]; then
+    return;
+  fi
+
+  #
+  # Clear the previous result.
+  #
+  _history_substring_search_result=''
+
+  if [[ -z $BUFFER ]]; then
+    #
+    # If the buffer is empty, we will just act like up-history/down-history
+    # in ZSH, so we do not need to actually search the history. This should
+    # speed things up a little.
+    #
+    _history_substring_search_query=
+    _history_substring_search_query_parts=()
+    _history_substring_search_raw_matches=()
+
+  else
+    #
+    # For the purpose of highlighting we keep a copy of the original
+    # query string.
+    #
+    _history_substring_search_query=$BUFFER
+
+    #
+    # compose search pattern
+    #
+    if [[ -n $HISTORY_SUBSTRING_SEARCH_FUZZY ]]; then
+      #
+      # `=` split string in arguments
+      #
+      _history_substring_search_query_parts=(${=_history_substring_search_query})
+    else
+      _history_substring_search_query_parts=(${==_history_substring_search_query})
+    fi
+
+    #
+    # Escape and join query parts with wildcard character '*' as separator
+    # `(j:CHAR:)` join array to string with CHAR as separator
+    #
+    local search_pattern="*${(j:*:)_history_substring_search_query_parts[@]//(#m)[\][()|\\*?#<>~^]/\\$MATCH}*"
+
+    #
+    # Find all occurrences of the search pattern in the history file.
+    #
+    # (k) returns the "keys" (history index numbers) instead of the values
+    # (R) returns values in reverse older, so the index of the youngest
+    # matching history entry is at the head of the list.
+    #
+    _history_substring_search_raw_matches=(${(k)history[(R)(#$HISTORY_SUBSTRING_SEARCH_GLOBBING_FLAGS)${search_pattern}]})
+  fi
+
+  #
+  # In order to stay as responsive as possible, we will process the raw
+  # matches lazily (when the user requests the next match) to choose items
+  # that need to be displayed to the user.
+  # _history_substring_search_raw_match_index holds the index of the last
+  # unprocessed entry in _history_substring_search_raw_matches. Any items
+  # that need to be displayed will be added to
+  # _history_substring_search_matches.
+  #
+  # We use an associative array (_history_substring_search_unique_filter) as
+  # a 'set' data structure to ensure uniqueness of the results if desired.
+  # If an entry (key) is in the set (non-empty value), then we have already
+  # added that entry to _history_substring_search_matches.
+  #
+  _history_substring_search_raw_match_index=0
+  _history_substring_search_matches=()
+  _history_substring_search_unique_filter=()
+
+  #
+  # If $_history_substring_search_match_index is equal to
+  # $#_history_substring_search_matches + 1, this indicates that we
+  # are beyond the end of $_history_substring_search_matches and that we
+  # have also processed all entries in
+  # _history_substring_search_raw_matches.
+  #
+  # If $#_history_substring_search_match_index is equal to 0, this indicates
+  # that we are beyond the beginning of $_history_substring_search_matches.
+  #
+  # If we have initially pressed "up" we have to initialize
+  # $_history_substring_search_match_index to 0 so that it will be
+  # incremented to 1.
+  #
+  # If we have initially pressed "down" we have to initialize
+  # $_history_substring_search_match_index to 1 so that it will be
+  # decremented to 0.
+  #
+  if [[ $WIDGET == history-substring-search-down ]]; then
+     _history_substring_search_match_index=1
+  else
+    _history_substring_search_match_index=0
+  fi
+}
+
+_history-substring-search-end() {
+  setopt localoptions extendedglob
+
+  _history_substring_search_result=$BUFFER
+
+  # the search was successful so display the result properly by clearing away
+  # existing highlights and moving the cursor to the end of the result buffer
+  if [[ $_history_substring_search_refresh_display -eq 1 ]]; then
+    region_highlight=()
+    CURSOR=${#BUFFER}
+  fi
+
+  # highlight command line using zsh-syntax-highlighting
+  _zsh_highlight
+
+  # highlight the search query inside the command line
+  if [[ -n $_history_substring_search_query_highlight ]]; then
+    # highlight first matching query parts
+    local highlight_start_index=0
+    local highlight_end_index=0
+    local query_part
+    for query_part in $_history_substring_search_query_parts; do
+      local escaped_query_part=${query_part//(#m)[\][()|\\*?#<>~^]/\\$MATCH}
+      # (i) get index of pattern
+      local query_part_match_index="${${BUFFER:$highlight_start_index}[(i)(#$HISTORY_SUBSTRING_SEARCH_GLOBBING_FLAGS)${escaped_query_part}]}"
+      if [[ $query_part_match_index -le ${#BUFFER:$highlight_start_index} ]]; then
+        highlight_start_index=$(( $highlight_start_index + $query_part_match_index ))
+        highlight_end_index=$(( $highlight_start_index + ${#query_part} ))
+        region_highlight+=("$(($highlight_start_index - 1)) $(($highlight_end_index - 1)) $_history_substring_search_query_highlight")
+      fi
+    done
+  fi
+
+  # For debugging purposes:
+  # zle -R "mn: "$_history_substring_search_match_index" m#: "${#_history_substring_search_matches}
+  # read -k -t 200 && zle -U $REPLY
+
+  # Exit successfully from the history-substring-search-* widgets.
+  return 0
+}
+
+_history-substring-search-up-buffer() {
+  #
+  # Check if the UP arrow was pressed to move the cursor within a multi-line
+  # buffer. This amounts to three tests:
+  #
+  # 1. $#buflines -gt 1.
+  #
+  # 2. $CURSOR -ne $#BUFFER.
+  #
+  # 3. Check if we are on the first line of the current multi-line buffer.
+  #    If so, pressing UP would amount to leaving the multi-line buffer.
+  #
+  #    We check this by adding an extra "x" to $LBUFFER, which makes
+  #    sure that xlbuflines is always equal to the number of lines
+  #    until $CURSOR (including the line with the cursor on it).
+  #
+  local buflines XLBUFFER xlbuflines
+  buflines=(${(f)BUFFER})
+  XLBUFFER=$LBUFFER"x"
+  xlbuflines=(${(f)XLBUFFER})
+
+  if [[ $#buflines -gt 1 && $CURSOR -ne $#BUFFER && $#xlbuflines -ne 1 ]]; then
+    zle up-line-or-history
+    return 0
+  fi
+
+  return 1
+}
+
+_history-substring-search-down-buffer() {
+  #
+  # Check if the DOWN arrow was pressed to move the cursor within a multi-line
+  # buffer. This amounts to three tests:
+  #
+  # 1. $#buflines -gt 1.
+  #
+  # 2. $CURSOR -ne $#BUFFER.
+  #
+  # 3. Check if we are on the last line of the current multi-line buffer.
+  #    If so, pressing DOWN would amount to leaving the multi-line buffer.
+  #
+  #    We check this by adding an extra "x" to $RBUFFER, which makes
+  #    sure that xrbuflines is always equal to the number of lines
+  #    from $CURSOR (including the line with the cursor on it).
+  #
+  local buflines XRBUFFER xrbuflines
+  buflines=(${(f)BUFFER})
+  XRBUFFER="x"$RBUFFER
+  xrbuflines=(${(f)XRBUFFER})
+
+  if [[ $#buflines -gt 1 && $CURSOR -ne $#BUFFER && $#xrbuflines -ne 1 ]]; then
+    zle down-line-or-history
+    return 0
+  fi
+
+  return 1
+}
+
+_history-substring-search-up-history() {
+  #
+  # Behave like up in ZSH, except clear the $BUFFER
+  # when beginning of history is reached like in Fish.
+  #
+  if [[ -z $_history_substring_search_query ]]; then
+
+    # we have reached the absolute top of history
+    if [[ $HISTNO -eq 1 ]]; then
+      BUFFER=
+
+    # going up from somewhere below the top of history
+    else
+      zle up-line-or-history
+    fi
+
+    return 0
+  fi
+
+  return 1
+}
+
+_history-substring-search-down-history() {
+  #
+  # Behave like down-history in ZSH, except clear the
+  # $BUFFER when end of history is reached like in Fish.
+  #
+  if [[ -z $_history_substring_search_query ]]; then
+
+    # going down from the absolute top of history
+    if [[ $HISTNO -eq 1 && -z $BUFFER ]]; then
+      BUFFER=${history[1]}
+      _history_substring_search_refresh_display=1
+
+    # going down from somewhere above the bottom of history
+    else
+      zle down-line-or-history
+    fi
+
+    return 0
+  fi
+
+  return 1
+}
+
+_history_substring_search_process_raw_matches() {
+  #
+  # Process more outstanding raw matches and append any matches that need to
+  # be displayed to the user to _history_substring_search_matches.
+  # Return whether there were any more results appended.
+  #
+
+  #
+  # While we have more raw matches. Process them to see if there are any more
+  # matches that need to be displayed to the user.
+  #
+  while [[ $_history_substring_search_raw_match_index -lt $#_history_substring_search_raw_matches ]]; do
+    #
+    # Move on to the next raw entry and get its history index.
+    #
+    _history_substring_search_raw_match_index+=1
+    local index=${_history_substring_search_raw_matches[$_history_substring_search_raw_match_index]}
+
+    #
+    # If HISTORY_SUBSTRING_SEARCH_ENSURE_UNIQUE is set to a non-empty value,
+    # then ensure that only unique matches are presented to the user.
+    # When HIST_IGNORE_ALL_DUPS is set, ZSH already ensures a unique history,
+    # so in this case we do not need to do anything.
+    #
+    if [[ ! -o HIST_IGNORE_ALL_DUPS && -n $HISTORY_SUBSTRING_SEARCH_ENSURE_UNIQUE ]]; then
+      #
+      # Get the actual history entry at the new index, and check if we have
+      # already added it to _history_substring_search_matches.
+      #
+      local entry=${history[$index]}
+
+      if [[ -z ${_history_substring_search_unique_filter[$entry]} ]]; then
+        #
+        # This is a new unique entry. Add it to the filter and append the
+        # index to _history_substring_search_matches.
+        #
+        _history_substring_search_unique_filter[$entry]=1
+        _history_substring_search_matches+=($index)
+
+        #
+        # Indicate that we did find a match.
+        #
+        return 0
+      fi
+
+    else
+      #
+      # Just append the new history index to the processed matches.
+      #
+      _history_substring_search_matches+=($index)
+
+      #
+      # Indicate that we did find a match.
+      #
+      return 0
+    fi
+
+  done
+
+  #
+  # We are beyond the end of the list of raw matches. Indicate that no
+  # more matches are available.
+  #
+  return 1
+}
+
+_history-substring-search-has-next() {
+  #
+  # Predicate function that returns whether any more older matches are
+  # available.
+  #
+
+  if  [[ $_history_substring_search_match_index -lt $#_history_substring_search_matches ]]; then
+    #
+    # We did not reach the end of the processed list, so we do have further
+    # matches.
+    #
+    return 0
+
+  else
+    #
+    # We are at the end of the processed list. Try to process further
+    # unprocessed matches. _history_substring_search_process_raw_matches
+    # returns whether any more matches were available, so just return
+    # that result.
+    #
+    _history_substring_search_process_raw_matches
+    return $?
+  fi
+}
+
+_history-substring-search-has-prev() {
+  #
+  # Predicate function that returns whether any more younger matches are
+  # available.
+  #
+
+  if [[ $_history_substring_search_match_index -gt 1 ]]; then
+    #
+    # We did not reach the beginning of the processed list, so we do have
+    # further matches.
+    #
+    return 0
+
+  else
+    #
+    # We are at the beginning of the processed list. We do not have any more
+    # matches.
+    #
+    return 1
+  fi
+}
+
+_history-substring-search-found() {
+  #
+  # A match is available. The index of the match is held in
+  # $_history_substring_search_match_index
+  #
+  # 1. Make $BUFFER equal to the matching history entry.
+  #
+  # 2. Use $HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_FOUND
+  #    to highlight the current buffer.
+  #
+  BUFFER=$history[$_history_substring_search_matches[$_history_substring_search_match_index]]
+  _history_substring_search_query_highlight=$HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_FOUND
+}
+
+_history-substring-search-not-found() {
+  #
+  # No more matches are available.
+  #
+  # 1. Make $BUFFER equal to $_history_substring_search_query so the user can
+  #    revise it and search again.
+  #
+  # 2. Use $HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_NOT_FOUND
+  #    to highlight the current buffer.
+  #
+  BUFFER=$_history_substring_search_query
+  _history_substring_search_query_highlight=$HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_NOT_FOUND
+}
+
+_history-substring-search-up-search() {
+  _history_substring_search_refresh_display=1
+
+  #
+  # Select history entry during history-substring-down-search:
+  #
+  # The following variables have been initialized in
+  # _history-substring-search-up/down-search():
+  #
+  # $_history_substring_search_matches is the current list of matches that
+  # need to be displayed to the user.
+  # $_history_substring_search_match_index is the index of the current match
+  # that is being displayed to the user.
+  #
+  # The range of values that $_history_substring_search_match_index can take
+  # is: [0, $#_history_substring_search_matches + 1].  A value of 0
+  # indicates that we are beyond the beginning of
+  # $_history_substring_search_matches. A value of
+  # $#_history_substring_search_matches + 1 indicates that we are beyond
+  # the end of $_history_substring_search_matches and that we have also
+  # processed all entries in _history_substring_search_raw_matches.
+  #
+  # If $_history_substring_search_match_index equals
+  # $#_history_substring_search_matches and
+  # $_history_substring_search_raw_match_index is not greater than
+  # $#_history_substring_search_raw_matches, then we need to further process
+  # $_history_substring_search_raw_matches to see if there are any more
+  # entries that need to be displayed to the user.
+  #
+  # In _history-substring-search-up-search() the initial value of
+  # $_history_substring_search_match_index is 0. This value is set in
+  # _history-substring-search-begin(). _history-substring-search-up-search()
+  # will initially increment it to 1.
+  #
+
+  if [[ $_history_substring_search_match_index -gt $#_history_substring_search_matches ]]; then
+    #
+    # We are beyond the end of $_history_substring_search_matches. This
+    # can only happen if we have also exhausted the unprocessed matches in
+    # _history_substring_search_raw_matches.
+    #
+    # 1. Update display to indicate search not found.
+    #
+    _history-substring-search-not-found
+    return
+  fi
+
+  if _history-substring-search-has-next; then
+    #
+    # We do have older matches.
+    #
+    # 1. Move index to point to the next match.
+    # 2. Update display to indicate search found.
+    #
+    _history_substring_search_match_index+=1
+    _history-substring-search-found
+
+  else
+    #
+    # We do not have older matches.
+    #
+    # 1. Move the index beyond the end of
+    #    _history_substring_search_matches.
+    # 2. Update display to indicate search not found.
+    #
+    _history_substring_search_match_index+=1
+    _history-substring-search-not-found
+  fi
+
+  #
+  # When HIST_FIND_NO_DUPS is set, meaning that only unique command lines from
+  # history should be matched, make sure the new and old results are different.
+  #
+  # However, if the HIST_IGNORE_ALL_DUPS shell option, or
+  # HISTORY_SUBSTRING_SEARCH_ENSURE_UNIQUE is set, then we already have a
+  # unique history, so in this case we do not need to do anything.
+  #
+  if [[ -o HIST_IGNORE_ALL_DUPS || -n $HISTORY_SUBSTRING_SEARCH_ENSURE_UNIQUE ]]; then
+    return
+  fi
+
+  if [[ -o HIST_FIND_NO_DUPS && $BUFFER == $_history_substring_search_result ]]; then
+    #
+    # Repeat the current search so that a different (unique) match is found.
+    #
+    _history-substring-search-up-search
+  fi
+}
+
+_history-substring-search-down-search() {
+  _history_substring_search_refresh_display=1
+
+  #
+  # Select history entry during history-substring-down-search:
+  #
+  # The following variables have been initialized in
+  # _history-substring-search-up/down-search():
+  #
+  # $_history_substring_search_matches is the current list of matches that
+  # need to be displayed to the user.
+  # $_history_substring_search_match_index is the index of the current match
+  # that is being displayed to the user.
+  #
+  # The range of values that $_history_substring_search_match_index can take
+  # is: [0, $#_history_substring_search_matches + 1].  A value of 0
+  # indicates that we are beyond the beginning of
+  # $_history_substring_search_matches. A value of
+  # $#_history_substring_search_matches + 1 indicates that we are beyond
+  # the end of $_history_substring_search_matches and that we have also
+  # processed all entries in _history_substring_search_raw_matches.
+  #
+  # In _history-substring-search-down-search() the initial value of
+  # $_history_substring_search_match_index is 1. This value is set in
+  # _history-substring-search-begin(). _history-substring-search-down-search()
+  # will initially decrement it to 0.
+  #
+
+  if [[ $_history_substring_search_match_index -lt 1 ]]; then
+    #
+    # We are beyond the beginning of $_history_substring_search_matches.
+    #
+    # 1. Update display to indicate search not found.
+    #
+    _history-substring-search-not-found
+    return
+  fi
+
+  if _history-substring-search-has-prev; then
+    #
+    # We do have younger matches.
+    #
+    # 1. Move index to point to the previous match.
+    # 2. Update display to indicate search found.
+    #
+    _history_substring_search_match_index+=-1
+    _history-substring-search-found
+
+  else
+    #
+    # We do not have younger matches.
+    #
+    # 1. Move the index beyond the beginning of
+    #    _history_substring_search_matches.
+    # 2. Update display to indicate search not found.
+    #
+    _history_substring_search_match_index+=-1
+    _history-substring-search-not-found
+  fi
+
+  #
+  # When HIST_FIND_NO_DUPS is set, meaning that only unique command lines from
+  # history should be matched, make sure the new and old results are different.
+  #
+  # However, if the HIST_IGNORE_ALL_DUPS shell option, or
+  # HISTORY_SUBSTRING_SEARCH_ENSURE_UNIQUE is set, then we already have a
+  # unique history, so in this case we do not need to do anything.
+  #
+  if [[ -o HIST_IGNORE_ALL_DUPS || -n $HISTORY_SUBSTRING_SEARCH_ENSURE_UNIQUE ]]; then
+    return
+  fi
+
+  if [[ -o HIST_FIND_NO_DUPS && $BUFFER == $_history_substring_search_result ]]; then
+    #
+    # Repeat the current search so that a different (unique) match is found.
+    #
+    _history-substring-search-down-search
+  fi
+}
+
+# -*- mode: zsh; sh-indentation: 2; indent-tabs-mode: nil; sh-basic-offset: 2; -*-
+# vim: ft=zsh sw=2 ts=2 et