Expand dots to dot-dot component.

#
# Expand dots to dot-dot component (~/.bash_aliases).
#
# https://github.com/bac0n/bash_completion
#
if [ -n "$PS1" ]; then
cd(){
    local d=${@:(-1)}
    local x='' y='' z=3
    while [[ ! -d $d ]] && [[ ${d:${#x}} =~ (^|/)([.]{3,})(/.*)?$ ]]; do
        x=${d:0:(${#d} - ${#BASH_REMATCH[3]})}
        if [[ ! -d $x ]]; then
            y='..'
            for ((z=3; z <= ${#BASH_REMATCH[2]}; z++)); do
                y+='/..'
            done
            d=${d:0:(${#d} - ${#BASH_REMATCH[0]})}${BASH_REMATCH[1]}${y}${BASH_REMATCH[3]}
        fi
    done
    builtin pushd "$d" > /dev/null && /bin/ls --almost-all --color=auto
}

cd_undo(){
    if [[ ${READLINE_LINE%% *} != cd ]]; then
        return
    fi
    local d='' x='' y='' z=0
    READLINE_LINE=${READLINE_LINE%/}
    d=$(rev <<< ${READLINE_LINE#* })
    if [[ $d =~ (^|/)([.]{2}(/[.]{2})+)(/.*)?$ ]]; then
        y=.
        x=${BASH_REMATCH[2]//\/}
        for ((z=0; z < (${#x} / 2); z++)); do
            y+=.
        done
        x=${d:0:(${#d} - ${#BASH_REMATCH[0]})}
        READLINE_LINE="cd $(rev <<< ${x}${BASH_REMATCH[1]}${y}${BASH_REMATCH[4]})"
        READLINE_POINT=$((${#READLINE_LINE} - ${#x} - ${#BASH_REMATCH[1]}))
    else
        i=0
        x=$((${#READLINE_LINE} - $READLINE_POINT))
        while [[ ${d:$x} =~ (^|/)([.]{3,})(/.*)?$ ]]; do
            x=$((${#d} - ${#BASH_REMATCH[3]}))
            if (( (${#BASH_REMATCH[2]} + ${#BASH_REMATCH[3]}) == ($READLINE_POINT - 3) )); then
                continue
            fi
            READLINE_POINT=$((${#BASH_REMATCH[0]} - ${#BASH_REMATCH[1]} + 3))
            break
        done
    fi
}

    # bind cd undo to readline keyseq ESC ESC.
    if [[ $(declare -F cd_undo) = cd_undo ]]; then
        bind -r '"\e\e"'
        bind -x '"\e\e"  :cd_undo'
        bind -x '"\e\e\e":cd_undo'
    fi
fi

##

# (/etc/bash_completion.d/cd)
#
# This meta-cd function observes the CDPATH variable, so that cd additionally
# completes on directories under those specified in CDPATH.
#
_cd()
{
    local cur prev words cword
    _init_completion || return

    local IFS=$'\n' i j k

    compopt -o filenames

    # Expand dots to dot-dot component.
    local x='' y='' z=3
    while [[ ! -d $cur ]] && [[ ${cur:${#x}} =~ (^|/)([.]{3,})(/.*)?$ ]]; do
        if [[ -n $(compgen -d -- $cur) ]]; then
            if [[ $cur == ..+(.) ]] || [[ $cur == */..+(.) ]]; then
                COMPREPLY+=("$cur/")
            fi
            break
        fi
        x="${cur:0:(${#cur}-${#BASH_REMATCH[3]})}"
        if [[ ! -d $x ]]; then
            y='..'
            for ((z=3; z <= ${#BASH_REMATCH[2]}; z++)); do
                y+='/..'
            done
            cur="${cur:0:(${#cur}-${#BASH_REMATCH[0]})}${BASH_REMATCH[1]}${y}${BASH_REMATCH[3]}"
        fi
    done

    # Use standard dir completion if no CDPATH or parameter starts with /,
    # ./ or ../
    if [[ -z "${CDPATH:-}" || "$cur" == ?(.)?(.)/* ]]; then
        _filedir -d
        return
    fi

    local -r mark_dirs=$(_rl_enabled mark-directories && echo y)
    local -r mark_symdirs=$(_rl_enabled mark-symlinked-directories && echo y)

    # we have a CDPATH, so loop on its contents
    for i in ${CDPATH//:/$'\n'}; do
        # create an array of matched subdirs
        k="${#COMPREPLY[@]}"
        for j in $( compgen -d -- $i/$cur ); do
            if [[ ( $mark_symdirs && -h $j || $mark_dirs && ! -h $j ) && ! -d ${j#$i/} ]]; then
                j+="/"
            fi
            COMPREPLY[k++]=${j#$i/}
        done
    done

    _filedir -d

    if [[ ${#COMPREPLY[@]} -eq 1 ]]; then
        i=${COMPREPLY[0]}
        if [[ "$i" == "$cur" && $i != "*/" ]]; then
            COMPREPLY[0]="${i}/"
        fi
    fi
    return
}

if shopt -q cdable_vars; then
    complete -v -F _cd -o nospace cd pushd
else
    complete -F _cd -o nospace cd pushd
fi