taskfile ("make-like" but in bash) with better docs generation than the original

gistfile1.txt

# this comment will be in the help text for a_task
function a_task() {
    ...
}

# prints this help text
function help() {
    # @todo allow a tag such as `# @internal` to denote functions as not available for external execution
    declare -A DESCRIPTIONS
    local CMD MAX LEN
    echo "$0 <task> <args>"
    echo "Tasks:"
    MAX=-1
    for CMD in $(compgen -A function); do
        LEN=${#CMD}
        ((LEN > MAX)) && MAX=$LEN
        DESCRIPTIONS[$CMD]=$(grep "function $CMD(" -B 1 "${BASH_SOURCE[0]}" | grep '^#' | grep -v '@todo' | sed 's/^# *//')
    done
    MAX=$((MAX + 4))
    for CMD in $(compgen -A function); do
        if [ -z "${DESCRIPTIONS[$CMD]}" ]; then
            echo "    ${CMD}"
        else
            printf "%-${MAX}s %s\n" "    ${CMD}" "${DESCRIPTIONS[$CMD]}"
            #echo "    ${CMD}: ${DESCRIPTIONS[$CMD]}"
        fi

    done
}

if [ $# -eq 0 ]; then
    help
else
    cd "$(dirname -- "$(realpath "${BASH_SOURCE[0]}")")"

    TIMEFORMAT="Task completed in %3lR"
    time ${@}
fi