Bash mandatory and typed input by read overload

read-overload-1.sh

#!/bin/bash

function read {
	declare -n var="${@: -1}"
	case "$1" in
		-Z) until [[ -n "$var" ]]; do
				builtin read "${@:2}";
			done ;;
		-D) until [[ "$var" =~ ^[0-9]+$ ]]; do
				builtin read "${@:2}";
			done ;;
		-R) until [[ "$var" =~ ^[0-9]+$ ]]; do
				IFS='-' builtin read "${@:2}"
			done ;;
		 *) builtin read "$@";;
	esac
	unset var
}

read -p    "Please enter something: " opt && echo "opt=$opt"
read -Z -p "Do enter something: " str && echo "str=$str"
read -D -p "Do enter a number: " num && echo "num=$num"
read -R -p "Do enter a range: " n m && echo "range=[$n $m]"
read -D -p "Please enter 2 numbers: " n m && echo "[$n $m]"

read-overload-2.sh

#!/bin/bash

function read {
	case "$1" in
		-Z) RE='.+'; shift;;
		-D) RE='^[0-9]+$'; shift;;
		-R) RE='^[0-9]+$' IFS='-'; shift;;
	esac

	declare -n var="${@: -1}"
	until
		builtin read "$@"
		[[ "$var" =~ $RE ]]
	do continue
	done
	unset IFS # reset to default
}

read -p    "Please enter something: " opt && echo "opt=$opt"
read -Z -p "Do enter something: " str && echo "str=$str"
read -D -p "Do enter a number: " num && echo "num=$num"
read -R -p "Do enter a range: " n m && echo "range=[$n $m]"
read -D -p "Please enter 2 numbers: " n m && echo "[$n $m]"