Mastering Modern Perl: Writing Efficient and Maintainable Code/

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Solution Review: Batch Calculator

Solution Review: Batch Calculator

See the solution to the batch calculator exercise.

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Solution

Let’s look at the solution before jumping into the explanation:

Perl
my %operations = (
    plus => sub { $_[0] + $_[1] },
    minus => sub { $_[0] - $_[1] },
    times => sub { $_[0] * $_[1] },
    dividedby => sub { $_[0] / $_[1] },
    raisedto => sub { $_[0] ** $_[1] },
);
sub calculate {
    my (@array) = @_;
    my @results;
    
    foreach my $subarray (@array) {
        my ($operand1, $op, $operand2) = @$subarray;
        next unless exists $operations{ $op } and @$subarray == 3;
        push @results, $operations{ $op }->( $operand1, $operand2 );
    }
    print "@results";
}

Explanation

Let's go through the solution step by step:

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