$ set -x

$ read_value 'What is your surname? ' surname 'Not provided'
+ read_value 'What is your surname? ' surname 'Not provided'
+ local 'prompt=What is your surname? '
+ local outputname=surname
+ local 'default=Not provided'
+ local var
+ [[ -n Not provided ]]
+ default='-i '\''Not provided'\'''
+ eval 'read -r -e -i '\''Not provided'\'' -p '\''What is your surname? '\'' var'
++ read -r -e -i 'Not provided' -p 'What is your surname? ' var
What is your surname? Putin
+ res=0
+ [[ 0 -ne 0 ]]
+ eval 'surname='\''Putin'\'''
++ surname=Putin
+ return 0

$ set +x; echo "$surname"
+ set +x
Putin