Re^2: param = 0, not NULL

This is interesting.. an empty hash is false, but an empty hash reference.. is TRUE. :-)

#!/usr/bin/perl -w
my %hash = ();
%hash or print "empty hash is false\n";

my $hash = {};
print "empty hash ref is true\n" if $hash ;
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Re^3: param = 0, not NULL by davorg (Chancellor) on Mar 29, 2007 at 13:26 UTC
There is no such thing as an "empty hash reference". Or, if there is then the only possible meaning that it could have would be an undefined scalar. I think you mean "a reference to an empty hash is TRUE". And that's because Perl has already allocated storage for the hash and given you a reference to it. And a reference is always true. -- See the Copyright notice on my home node. "The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg	[reply]

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Re^3: param = 0, not NULL
by davorg (Chancellor) on Mar 29, 2007 at 13:26 UTC

There is no such thing as an "empty hash reference". Or, if there is then the only possible meaning that it could have would be an undefined scalar.

I think you mean "a reference to an empty hash is TRUE". And that's because Perl has already allocated storage for the hash and given you a reference to it. And a reference is always true.

See the Copyright notice on my home node.

"The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg

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