Perl YAML parser embedded in Bash

parse-yaml.sh

#!/usr/bin/env bash

set -e

function parse_yaml {
   local source="$1"
   local prefix="$2"

   cat "$source" | perl -MCPAN::Meta::YAML <(cat <<'EOF'
$yaml_str = do { local $/; <STDIN> };
$yaml = CPAN::Meta::YAML->read_string($yaml_str) or die CPAN::Meta::YAML->errstr;

@check = ( { val => $yaml->[0], pre => '' } );
while (my $check = shift @check) {
   if (ref $check->{val} eq 'ARRAY') {
      my $i;
      unshift @check, map { { val => $_, pre => $check->{pre}.'_'.$i++ } } @{$check->{val}};
      next;
   }
   if (ref $check->{val} eq 'HASH') {
      unshift @check, map { { val => $check->{val}->{$_}, pre => $check->{pre}.'_'.$_ } } sort keys %{$check->{val}};
      next;
   }
   $check->{pre} =~ s/-/_/g;
   printf "%s=\"%s\"\n", $check->{pre}, $check->{val};
}
EOF
) | perl -pe "s/^/$prefix/"
}

parse_yaml "test.yaml" "CONF_"

test.yaml

top1:
  ei-ns:
   - aa
   - bb
  zwei: cc
top2: dd