gistfile1.txt

#   class RecommendationTracker
#     def add_recommendation(recommender, business)
#       has_recommender_recommended_business?(recommender, business) do
#         raise StandardError, 'You may only recommend the same business once.'
#       end
#
#       @recommendations[business] << recommender
#     end
#
#     def recommendation_totals
#       recommendation_totals = Hash.new
#
#       @recommendations.each_key do |business|
#         recommendation_totals[business] =  @recommendations[business].length
#       end
#
#       recommendation_totals
#     end
#
#   private
#     def initialize
#       @recommendations = Hash.new do |recommendations, business|
#         recommendations[business] = Array.new
#       end
#     end
#
#     def has_recommender_recommended_business?(recommender, business)
#       return false if [email protected]_key? business
#       return false if !@recommendations[business].include?(recommender)
#
#       yield
#       true
#     end
# end

use 5.10.0;
use MooseX::Declare;
use MooseX::AttributeHelpers;

class ReccomendationTracker {
    has recommended_business => (
        isa     => 'HashRef[ArrayRef]',
        is      => 'ro',
        default => sub { {} },
    );

    method add_recommendation( $reccomender, $business ) {
        confess 'You may only recommend the same business once.'
            if $self->recommended_business->{$business} ~~ $reccomender;

        $self->recommended_business->{$business} //= [];
        push $self->recommended_business->{$business}, $reccomender;
    };

    method recommendation_totals() {
        return {
            map { $_ => scalar @{$_} }
                keys %{ $self->recommended_business }
        }
    };
}