gistfile1.txt

function introspect {
        if [[ ${FUNCNAME[0]} != "${FUNCNAME[1]}" ]]; then
                typeset ret
                if ! shopt -qo pipefail; then shopt -so pipefail; ret+='shopt -uo pipefail; '; fi
                if shopt -qo monitor; then shopt -uo monitor; ret+='shopt -so monitor; '; fi
                if ! shopt -q lastpipe; then shopt -s lastpipe; ret+='shopt -u lastpipe; '; fi
                eval "\\${FUNCNAME[0]} \"\$@\"; ${ret}"
        fi

        unset -v ret
        typeset -A optnames=(
                [alias]=
                [arrayvar]=
                [binding]=
                [builtin]=
                [command]=
                [directory]=
                [disabled]=
                [enabled]=
                [export]=
                [file]=
                [function]=
                [group]=
                [helptopic]=
                [hostname]=
                [job]=
                [keyword]=
                [running]=
                [service]=
                [setopt]=
                [shopt]=
                [signal]=
                [stopped]=
                [user]=
                [variable]=
        )

        typeset opt=1 arg=2
        for ((; opt <= $#; arg = ((opt += 2) + 1) )); do
                if [[ ! ( ${!opt} =~ ^--([[:alpha:]]+)$ && -v optnames[${BASH_REMATCH[1]}] ) ]]; then
                        printf 'invalid option: %s\n' "${!opt}" >&2
                        return 1
                fi

                compgen -A "${BASH_REMATCH[1]}" | mapfile -t -- "${!arg}" || return
        done
}