On 17 Aug 2002, Peter Behroozi wrote: : However, since you forced me to read through A5 again, I now have : another question :). Since we can now do : : $string.tr %hash; : : what happens when the keys of %hash have overlapping ranges by accident : or otherwise? Are there any other options than reporting an overlap : (hard), auto-sorting the key-value pairs (medium), or not allowing : hashes (easy)?
Doing tr efficiently generally requires precompilation, so in the case of a hash, the compiled result would be stored as a run-time property. So we can really do whatever processing we want, on the assumption that the hash will change much less frequently than it gets used. Alternatively, we could restrict hashes to single character translations. But under UTF-8 that doesn't guarantee a constant string length (as measured in bytes). But I would guess that hashes would be used for even longer sequences of characters too, so some amount of preprocessing would be desirable to determine if one key was a prefix of another. Maybe it wants to get translated to some sort of trie parser. Really just depends on how much memory we want to throw at it to make it fast. Larry
