Created
December 23, 2014 15:57
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Rubyでレコード型っぽいデータ型を作るテスト
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| class RecordInstance | |
| attr_reader :klass, :members | |
| def initialize(klass, hash) | |
| unless klass.members.all?{|name, type| hash.has_key?(name) && hash[name].is_a?(type)} | |
| raise "Instance initialization error!!" | |
| end | |
| @klass = klass | |
| @members = klass.members.keys.inject({}){|acc, name| acc.merge(name => hash[name])} | |
| end | |
| def is_like?(klass) | |
| klass.members.all?{|name, type| @klass.members.has_key?(name) && @klass.members[name] == type} | |
| end | |
| def alt(alternative) | |
| RecordInstance.new(@klass, @members.merge(alternative)) | |
| end | |
| def method_missing(message, *args, &block) | |
| if args.length == 0 && @members.has_key?(message) | |
| return @members[message] | |
| end | |
| super | |
| end | |
| end | |
| class RecordClass | |
| attr_reader :members | |
| def initialize(hash) | |
| unless hash.values.all?{|type| type.instance_of?(Class)} | |
| raise "Invalid specification of member's Type!!" | |
| end | |
| @members = hash | |
| end | |
| def +(other) | |
| unless @members.all?{|name, type| !other.members[name] || other.members[name] == type} | |
| raise "Conflict merging!!" | |
| end | |
| return RecordClass.new(other.members.merge(@members)) | |
| end | |
| def new(hash) | |
| return RecordInstance.new(self, hash) | |
| end | |
| end | |
| def Record(hash) | |
| RecordClass.new(hash) | |
| end | |
| def Def(name, signature, &definition) | |
| arg_type = signature.keys.first | |
| ret_type = signature.values.first | |
| define_method(name) do |arg| | |
| unless arg.instance_of?(RecordInstance) && arg.is_like?(arg_type) | |
| p arg, arg_type | |
| raise "Apply Error: cannot apply #{name} to #{arg}!!" | |
| end | |
| res = definition.call(arg) | |
| unless res.instance_of?(RecordInstance) && res.is_like?(ret_type) | |
| raise "Apply Error: evaluated value is invalid!!" | |
| end | |
| break res | |
| end | |
| end | |
| #----------------------------------------------------------------------------------------- | |
| Animal = Record(age: Integer, sex: Symbol) | |
| Human = Animal + Record(name: String) | |
| Something = Record(age: Integer) | |
| me = Human.new(name: "GOMIKUZU", age: 12, sex: :male) | |
| Def :aging, Something => Something do |r| | |
| r.alt(age: r.age * 2) | |
| end | |
| p aging(me) |
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