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Easy Initializer for Ruby Class
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| module EasyInitializer | |
| # rubocop:disable Metrics/CyclomaticComplexity, Metrics/AbcSize, Metrics/MethodLength, Metrics/PerceivedComplexity | |
| def initialize_with(*attributes, **config) | |
| named_params = _prepare_named_params config[:named_params] | |
| getter = attributes + named_params.keys | |
| # define accessors | |
| instance_eval do | |
| attr_reader(*getter) | |
| attr_writer(*getter) if config.fetch(:writable, true) | |
| config.fetch(:private_new_method, true) ? private_class_method(:new) : public_class_method(:new) | |
| end | |
| define_method :initialize do |*args| | |
| params = attributes.dup | |
| unless args.size >= params.size | |
| raise ArgumentError, "Wrong number of arguments (given #{args.size}, expected #{params.size})" | |
| end | |
| params.size.times { instance_variable_set("@#{params.shift}", args.shift) } | |
| options = args&.first || {} | |
| named_params.each do |key, default| | |
| instance_variable_set("@#{key}", options[key] || (default unless options.key?(key))) | |
| end | |
| __send__(config[:after]) if config.key?(:after) | |
| end | |
| end | |
| # rubocop:enable Metrics/CyclomaticComplexity, Metrics/AbcSize, Metrics/MethodLength, Metrics/PerceivedComplexity | |
| def callable(enable: true, instance_method: :call) | |
| return unless enable | |
| define_singleton_method :call do |*args| | |
| new(*args).public_send(instance_method) | |
| end | |
| end | |
| private | |
| def _prepare_named_params(named_params) | |
| Array(named_params).each_with_object({}) do |item, hash| | |
| hash.merge!(item.is_a?(Hash) ? item : { item => nil }) | |
| end | |
| end | |
| end | |
| class Base | |
| extend EasyInitializer | |
| callable | |
| end | |
| class Foo < Base | |
| initialize_with( | |
| :foo, :bar, | |
| named_params: [:params, test: 'default'], | |
| after: :valid!, | |
| writable: false, | |
| private_new_method: false | |
| ) | |
| def call | |
| { | |
| foo: foo, | |
| bar: bar, | |
| params: params, | |
| test: test | |
| } | |
| end | |
| private | |
| def valid! | |
| true | |
| end | |
| end | |
| Foo.call('foo-value', 'bar-value', params: 'params-value') | |
| # => {:foo=>"foo-value", :bar=>"bar-value", :params=>"params-value", :test=>"default"} | |
| Foo.call('foo-value', 'bar-value', params: 'params-value', test: 'test-value') | |
| # => {:foo=>"foo-value", :bar=>"bar-value", :params=>"params-value", :test=>"test-value"} | |
| Foo.call('foo', params: 'params') | |
| # => {:foo=>"foo", :bar=>{:params=>"params"}, :params=>nil, :test=>"default"} | |
| Foo.call('foo') | |
| # => ArgumentError: Wrong number of arguments (given 1, expected 2) | |
| class Bar < Base | |
| initialize_with :foo, named_params: [test: :test] | |
| callable instance_method: :run | |
| def run | |
| { | |
| foo: foo, | |
| test: test | |
| } | |
| end | |
| end | |
| Bar.call('foo') | |
| # => {:foo=>"foo", :test=>:test} | |
| Bar.call('foo', test: 'value') | |
| # => {:foo=>"foo", :test=>"value"} | |
| Bar.new | |
| # => NoMethodError: private method `new' called for Bar:Class |
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