The problem can be avoided by calling keys before each. 
keys %$ht;  # Reset iterator
while (my ($key, $value) = each(%$ht)) {

[download]

Update: Checked source to make sure it's efficient. Yes it is. It doesn't enumerate the keys at all in void context.

In reply to Re^4: Hash value interpolation by ikegami
in thread Hash value interpolation by csarid

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