BASH: Variable substitution on user input

prompt.sh

#!/bin/bash
  
set -e 

name=

_prompt() {
    local message="$1"
    local -n input="$2"

    while [ -z $input ]; do
        printf "$message\n"
        
        read input
    done
    
    echo $input
}

_prompt "What is your name?" name

echo "Your name is ${name}!"