lib/dry/monads.rb in dry-monads-1.1.0 vs lib/dry/monads.rb in dry-monads-1.2.0

@@ -1,14 +1,54 @@
+require 'dry/monads/registry'
+
 module Dry
   # Common, idiomatic monads for Ruby
   #
   # @api public
   module Monads
     def self.included(base)
-      if const_defined?(:CONSTRUCTORS)
-        base.include(*CONSTRUCTORS)
+      if all_loaded?
+        base.include(*constructors)
       else
         raise "Load all monads first with require 'dry/monads/all'"
+      end
+    end
+
+    # Build a module with cherry-picked monads.
+    # It saves a bit of typing when you add multiple
+    # monads to one class. Not loaded monads get loaded automatically.
+    #
+    # @example
+    #   require 'dry/monads'
+    #
+    #   class CreateUser
+    #     include Dry::Monads[:result, :do]
+    #
+    #     def initialize(repo, send_email)
+    #       @repo = repo
+    #       @send_email = send_email
+    #     end
+    #
+    #     def call(name)
+    #       if @repo.user_exist?(name)
+    #         Failure(:user_exists)
+    #       else
+    #         user = yield @repo.add_user(name)
+    #         yield @send_email.(user)
+    #         Success(user)
+    #       end
+    #     end
+    #   end
+    #
+    # @param [Array<Symbol>] monads
+    # @return [Module]
+    # @api public
+    def self.[](*monads)
+      monads.sort!
+      @mixins.fetch_or_store(monads.hash) do
+        monads.each { |m| load_monad(m) }
+        mixins = monads.map { |m| registry.fetch(m) }
+        Module.new { include(*mixins) }.freeze
       end
     end
   end
 end