Programming Perl, 4th Edition

Pseudohashes

A pseudohash used to be a way to treat an array as though it were a hash so you could fake an ordered hash. Pseudohashes were an experiment that turned out to be not such a great idea, so they have been removed from Perl as of v5.10, but some people are stuck on even earlier versions, so we’ll leave in a note, even though you shouldn’t use them. If you used them, you should have used the fields module’s phash and new functions.

The fields::phash interface is no longer available as of v5.10, although fields::new still works. Nonetheless, you should consider using restricted hashes from the standard Hash::Util module instead.