This is the README file for Hash::NoVivify

Hash::NoVivify is an XS extension that implements Non-Vivifying
defined and exists functions (Hash::NoVivify::Defined and
Hash::NoVivify::Exists, respectively).

When used on a hash, the exists() and defined() functions will create
(vivify) entries in a hash in order to evaluate the function.

For instance, the code

    %a = (a => 1, b=> 2);
    print "Doesn't exist\n" unless exists($a{c});
    print "Also Doesn't exist\n" unless exists($a{c}->{d});
    print "Oh, my, not good\n" if exists($a{c});

will print out:

    Doesn't exist
    Also Doesn't exist
    Oh, my, not good

The Hash::NoVivify module provides two functions,
Hash::NoVivify::Defined() and Hash::NoVivify::Exists(), which avoid
this, at the cost of a slightly convoluted syntax. Both functions take
a reference to a hash, followed by a list of descending keys defining
the hash entry to be investigated.

To build and install this extension, the usual

    perl Makefile.PL
    make
    make test
    make install

will suffice.

Hash::NoVivify requires perl5.004, and is

Copyright(c) 1999 Brent B. Powers. All rights reserved. This program
is free software, you may redistribute it and/or modify it under the
same terms as Perl itself.
