1accessors::ro(3) User Contributed Perl Documentation accessors::ro(3)
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6 accessors::ro - create 'classic' read-only accessor methods in caller's
7 package.
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10 package Foo;
11 use accessors::ro qw( foo bar baz );
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13 my $obj = bless { foo => 'read only? ' }, 'Foo';
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15 # values are read-only, so set is disabled:
16 print "oh my!\n" if $obj->foo( "set?" ) eq 'read only? ';
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18 # if you really need to change the vars,
19 # you must use direct-variable-access:
20 $obj->{bar} = 'i need a drink ';
21 $obj->{baz} = 'now';
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23 # always returns the current value:
24 print $obj->foo, $obj->bar, $obj->baz, "!\n";
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27 The accessors::ro pragma lets you create simple classic read-only
28 accessors at compile-time.
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30 The generated methods look like this:
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32 sub foo {
33 my $self = shift;
34 return $self->{foo};
35 }
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37 They always return the current value, just like accessors::ro.
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40 There is little-to-no performace hit when using generated accessors; in
41 fact there is usually a performance gain.
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43 · typically 5-15% faster than hard-coded accessors (like the above
44 example).
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46 · typically 0-15% slower than optimized accessors (less readable).
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48 · typically a small performance hit at startup (accessors are created
49 at compile-time).
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51 · uses the same anonymous sub to reduce memory consumption (sometimes
52 by 80%).
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54 See the benchmark tests included with this distribution for more
55 details.
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58 Classes using blessed scalarrefs, arrayrefs, etc. are not supported for
59 sake of simplicity. Only hashrefs are supported.
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62 Steve Purkis <spurkis@cpan.org>
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65 accessors, accessors::rw, accessors::classic, accessors::chained, base
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69perl v5.30.0 2019-07-26 accessors::ro(3)