function venv -d "Manipulate Python virtual environments (venv)"

    if test (count $argv) -eq 0
        echo "usage: venv [list | deactivate | activate VENV]"
        return 1
    end

    if test $argv[1] = "list" -o $argv[1] = "l"
        printf "%10s %10s %10s\n" "Name" "Version" "IPython"
        for venv in (ls $WORKON_HOME)
            set venv_path "$WORKON_HOME/$venv"
            set venv_version ($venv_path/bin/python --version | cut -d' ' -f 2)
            set venv_ipython (command -v $venv_path/bin/ipython > /dev/null && echo "yes" || echo "no")
            printf "%10s %10s %10s\n" "$venv" "$venv_version" "$venv_ipython"
        end
    else if test $argv[1] = "deactivate" -o $argv[1] = "d"
        type -q deactivate; and deactivate
    else if test $argv[1] = "activate" -o $argv[1] = "a"
        source $WORKON_HOME/{$argv[2]}/bin/activate.fish
    else if test $argv[1] = "remove" -o $argv[1] = "r"
        set venv_folder $WORKON_HOME/{$argv[2]}
        if set -q VIRTUAL_ENV && test $VIRTUAL_ENV = $venv_folder
            deactivate
        end
        rm -rf $venv_folder
    else
        return 1
    end
    return 0
end

# see http://fishshell.com/docs/current/completions.html

# disable file completions
complete -c venv -f

# subcommand completion
set -l commands list deactivate activate remove
complete -c venv -n "not __fish_seen_subcommand_from $commands" -a "$commands"

# activate completion
complete -c venv -n "__fish_seen_subcommand_from a" \
    -a "(ls $WORKON_HOME)"
complete -c venv -n "__fish_seen_subcommand_from activate" \
    -a "(ls $WORKON_HOME)"

complete -c venv -n "__fish_seen_subcommand_from r" \
    -a "(ls $WORKON_HOME)"
complete -c venv -n "__fish_seen_subcommand_from remove" \
    -a "(ls $WORKON_HOME)"