parse yaml in pure bash

parse-yaml.sh

#!/usr/bin/env bash

ryml () { local IFS=': ' ; read E C ;}

while ryml; do # alternatively: while IFS=': ' read E C; do
    case $E in
        parent)
            parent=${E} ;;
        child)
            echo ${parent}.${E}: ${C} ;;
    esac
done < "${1-/dev/stdin}" # reverse: < <(tac < "${1-/dev/stdin}")