シェルスクリプトで再帰とwhile文

yes_or_no.sh

#!/bin/bash

function yes_or_no_recursive(){
    echo
    echo "Type yes or no."
    read answer
    case $answer in
        yes)
            echo -e "tyeped yes.\n"
            return 0
            ;;
        no)
            echo -e "tyeped no.\n"
            return 1
            ;;
        *)
            echo -e "cannot understand $answer.\n"
            yes_or_no_recursive
            ;;
    esac
}

yes_or_no_recursive

function yes_or_no_while(){
    while true;do
        echo
        echo "Type yes or no."
        read answer
        case $answer in
            yes)
                echo -e "tyeped yes.\n"
                return 0
                ;;
            no)
                echo -e "tyeped no.\n"
                return 1
                ;;
            *)
                echo -e "cannot understand $answer.\n"
                ;;
        esac
    done
}

yes_or_no_while

#function yes_or_no_select(){
#    PS3="Answer? "
#    while true;do
#        echo "Type 1 or 2."
#        select answer in yes no;do
#            case $answer in
#                yes)
#                    echo -e "tyeped yes.\n"
#                    return 0
#                    ;;
#                no)
#                    echo -e "tyeped no.\n"
#                    return 1
#                    ;;
#                *)
#                    echo -e "cannot understand your answer.\n"
#                    ;;
#            esac
#        done
#    done
#}
#
#yes_or_no_select