emulate -L zsh
setopt extendedglob

autoload -U read-from-minibuffer replace-string-again

local p1="Replace: " p2="   with: "
# Saving curwidget is necessary to avoid the widget name being overwritten.
local REPLY previous curwidget=$WIDGET

if (( ${+NUMERIC} )); then
  (( $NUMERIC > 0 )) && previous=1
else
  zstyle -t ":zle:$WIDGET" edit-previous && previous=1
fi

read-from-minibuffer $p1 ${previous:+$_replace_string_src} || return 1
_replace_string_src=$REPLY

read-from-minibuffer "$p1$_replace_string_src$p2" \
  ${previous:+$_replace_string_rep} || return 1
_replace_string_rep=$REPLY

replace-string-again $curwidget