"Perl Programmers Reference Guide (англ.) (программ.) /19.12.1998/ " - читать интересную книгу автора

interchangeable, that's not the case for hashes. Just
because you can subscript a list value like a normal array
does not mean that you can subscript a list value as a
hash. Likewise, hashes included as parts of other lists
(including parameters lists and return lists from
functions) always flatten out into key/value pairs.
That's why it's good to use references sometimes.

It is often more readable to use the => operator between
key/value pairs. The => operator is mostly just a more
visually distinctive synonym for a comma, but it also
arranges for its left-hand operand to be interpreted as a
string--if it's a bareword that would be a legal
identifier. This makes it nice for initializing hashes:

%map = (
red => 0x00f,
blue => 0x0f0,
green => 0xf00,
);

or for initializing hash references to be used as records:

$rec = {
witch => 'Mable the Merciless',
cat => 'Fluffy the Ferocious',
date => '10/31/1776',
};

or for using call-by-named-parameter to complicated
functions:




18 perl 5.005, patch 02 14/Jun/98





PERLDATA(1) Perl Programmers Reference Guide PERLDATA(1)


$field = $query->radio_group(
name => 'group_name',
values => ['eenie','meenie','minie'],
default => 'meenie',
linebreak => 'true',
labels => \%labels