Sounds like homework to me. So, just a minimal solution. 
sub r;
sub r {map {my $__ = $_; $_, map {"$__.$_"} r ${$_[0]}{$_}} keys %{$_[
+0]}}

[download]
Call the sub with your hashref.

In reply to Re: walking a hash by JavaFan
in thread walking a hash by rjl

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