Would it be that hard to convert to a sane setup? Make a little script that evals each config file as shown, then YAML::Dump's it out to another replacement config file...

The calling code would (probably) be easy to replace. This would lose any comments. But you mentioned the the config file is written to in multiple places, and I can't see how the comments would be getting added anyway in that case. I have a feeling I'm missing the complexity here...

$ cat hash.conf
foo => 'bar',
baz => 'quux',

$ perl -MYAML -0 -e '%h=eval<>; YAML::DumpFile( "$ARGV\.yml", \%h)' ha
+sh.conf

$ cat hash.conf.yml
---
baz: quux
foo: bar

$ perl -MYAML -MData::Dumper -e '$h = YAML::LoadFile( shift() ); print
+ Dumper $h' hash.conf.yml
$VAR1 = {
          'baz' => 'quux',
          'foo' => 'bar'
        };
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