Re^2: The Bad, the Ugly, and the Good of autovivification

[Anonymous Monk]

Yeah, unfortunally, for algorithms that use 'exists', clamping hashes doesn't make sense. Either the key is known to be there (so, no need for exist), or its existance is volotile, which means that clamping hash prevent the keys from being inserted.

Sure, you can unclamp the hash whenever you insert a new key, but then it might be easier to write your exist test as:

  $exists = exists $hash{key1} && exists $hash{key1}{key2};

[5mi11er]

I don't think the first part of your argument is strictly true. If you use the @key's option, it would be possible for keys to not exist, or to be added dynamically, thus you might still need to see if that key happened to exist or not.

However, you're correct that none of this stuff helps at all with respect to "auto-vivication". And your code example does appear to help work around the problem when dealing with nested structures.

Hmm, Merlyn recently posted a snippet that walked a structure to it's leaf nodes, maybe we could combine the ideas of that snippet with this code to create a new form of exists?

-Scott

PS. the last paragraph was written "tongue-in-cheek", but it's late, and I would not be at all surprised to come into work on Monday to find someone actually wrote such a beast...