Hash::Util - A selection of general-utility hash subroutines |
Hash::Util - A selection of general-utility hash subroutines
use Hash::Util qw(lock_keys unlock_keys lock_value unlock_value lock_hash unlock_hash);
%hash = (foo => 42, bar => 23); lock_keys(%hash); lock_keys(%hash, @keyset); unlock_keys(%hash);
lock_value (%hash, 'foo'); unlock_value(%hash, 'foo');
lock_hash (%hash); unlock_hash(%hash);
Hash::Util
contains special functions for manipulating hashes that
don't really warrant a keyword.
By default Hash::Util
does not export anything.
5.8.0 introduces the ability to restrict a hash to a certain set of keys. No keys outside of this set can be added. It also introduces the ability to lock an individual key so it cannot be deleted and the value cannot be changed.
This is intended to largely replace the deprecated pseudo-hashes.
lock_keys(%hash); lock_keys(%hash, @keys);
Restricts the given %hash's set of keys to @keys. If @keys is not
given it restricts it to its current keyset. No more keys can be
added. delete()
and exists()
will still work, but it does not effect
the set of allowed keys.
unlock_keys(%hash;)
Removes the restriction on the %hash's keyset.
lock_key (%hash, $key); unlock_key(%hash, $key);
Locks and unlocks an individual key of a hash. The value of a locked key cannot be changed.
%hash must have already been locked for this to have useful effect.
lock_hash(%hash);
lock_hash()
locks an entire hash, making all keys and values readonly.
No value can be changed, no keys can be added or deleted.
unlock_hash(%hash);
unlock_hash()
does the opposite of lock_hash(). All keys and values
are made read/write. All values can be changed and keys can be added
and deleted.
Michael G Schwern <schwern@pobox.com> on top of code by Nick Ing-Simmons and Jeffrey Friedl.
the Scalar::Util manpage, the List::Util manpage, the Hash::Util manpage
Hash::Util - A selection of general-utility hash subroutines |