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# File 'lib/tamiyo/value.rb', line 7
def self.new(*fields, &block)
Class.new do
attr_reader(:hash, *fields)
define_method(:initialize) do |*values|
raise ArgumentError.new("wrong number of arguments, #{values.size} for #{fields.size}") if fields.size != values.size
fields.zip(values) do |field, value|
instance_variable_set(:"@#{field}", value)
end
@hash = self.class.hash ^ values.hash
freeze
end
const_set :VALUE_ATTRS, fields
def self.with(hash)
unexpected_keys = hash.keys - self::VALUE_ATTRS
if unexpected_keys.any?
raise ArgumentError.new("Unexpected hash keys: #{unexpected_keys}")
end
new(*hash.values_at(*self::VALUE_ATTRS))
end
def ==(other)
eql?(other)
end
def eql?(other)
self.class == other.class && values == other.values
end
def values
self.class::VALUE_ATTRS.map { |field| send(field) }
end
class_eval &block if block_given?
end
end
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