in reply to Re^3: Idea: Moose Mutal Coercion
in thread Idea: Moose Mutual Coercion

A less-distracting example might be a ball with mass, velocity, and momentum (calculate the third given two). I still think reaching for a lazy-building pile of Moose goop is wrong, since it's way easier to just have a cache: 
sub momentum {
    my $self = shift;
    $self->{momentum} //= $self->{mass} * $self->{velocity};
}

[download]
but at least this may let people focus on the idea.

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Re^5: Idea: Moose Mutal Coercion
by BrowserUk (Patriarch) on Feb 15, 2012 at 14:31 UTC

    You think that the OP is suggesting that Moose herders use his module so that they can type this:

    package Equation_Problem; 
use Moose;
use MooseX::Invertible_Build;

has mass     => ( isa => Num);
has velocity => ( isa => Num);
has momentum => (
    isa => Num,
    invertible_build => {
        A => 'mass',
        B => 'velocity',
        via => 'A * B',
    },
);

    [download]

    To 'save' typing:

    package Equation_Problem; 
use Moose;

has mass     => ( isa => Num);
has velocity => ( isa => Num);

sub momentum {
    my $self = shift;
    $self->mass * $self->velocity;
}

    [download]

    Hm. It can't be that in(s)ane.

    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.

    The start of some sanity?
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[select]
      No. I guess the OP wants a class which you can initialize with any two attributes, but you can then ask for all three.
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        Ah! The hackers are gonna love this:

        package Hash::PassPhrase; 
 use Moose;
 use MooseX::Invertible_Build;

 has passPhrase    => ( isa => Str );
 has salt          => ( isa => Str );
 has hash => (
     isa => Str,
     invertible_build => {
         A => 'salt',
         B => 'passPhrase',
         via => 'crypt( A, B )',
     },
 );

        [download]
        With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.

        The start of some sanity?
[reply]
[d/l]

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