parse_yaml() {
   local prefix=$2
   local s='[[:space:]]*' w='[a-zA-Z0-9_]*' fs=$(echo @|tr @ '34')
   sed -ne "s|^($s)($w)$s:$s"(.*)"$s$|1$fs2$fs3|p"
        -e "s|^($s)($w)$s:$s(.*)$s$|1$fs2$fs3|p"  $1 |
   awk -F$fs '{
      indent = length($1)/2;
      vname[indent] = $2;
      for (i in vname) {if (i > indent) {delete vname[i]}}
      if (length($3) > 0) {
         vn=""; for (i=0; i<indent; i++) {vn=(vn)(vname[i])("_")}
         printf("%s%s%s="%s"n", "'$prefix'",vn, $2, $3); #How to return all values concated
      }
   }'
}

allContent=parse_yml.

r=$r$vn$2$3