Course of Raku / Objects, I/O, and exceptions / Classes and objects / Methods

Private attributes

In the section about attributes, each attribute was declared with $., which creates a public accessor. An attribute declared with $! instead is private: it has no accessor and cannot be seen from outside the object. It is reachable only from within the class’s own methods, where you refer to it as $!name.

class Safe {
    has $!code = 4321;

    method unlocks($attempt) {
        return $attempt == $!code;
    }
}

my $safe = Safe.new;
say $safe.unlocks(4321); # True
say $safe.unlocks(1111); # False

The secret $!code is stored inside the object but never exposed: there is no .code accessor, so the only way to interact with it is through the unlocks method that the class chooses to provide. An attempt to read $safe.code or $safe!code simply fails.

Private attributes are useful for internal details that the rest of the program should not touch directly.

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Private attributes

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