lib/atacama/contract.rb in atacama-0.1.3 vs lib/atacama/contract.rb in atacama-0.1.4

@@ -7,10 +7,27 @@
 module Atacama
   # The type namespace to interact with DRY::Types
   module Types
     include Dry::Types.module
     Boolean = Types::True | Types::False
+
+    def self.Option(**map)
+      Instance(Values::Option).constructor do |options|
+        map.each do |key, type|
+          type[options.value[key]]
+        end
+
+        options
+      end
+    end
+
+    def self.Return(type)
+      Instance(Values::Return).constructor do |options|
+        type[options.value]
+        options
+      end
+    end
   end
 
   # This class enables a DSL for creating a contract for the initializer
   class Contract
     RESERVED_KEYS = %i[call initialize context].freeze
@@ -24,33 +41,48 @@
       def injected=(hash)
         @injected = Types::Strict::Hash[hash]
       end
 
       def injected
-        @injected || {}
+        # Silences the VM warning about accessing uninitalized ivar
+        defined?(@injected) ? @injected : {}
       end
 
       def options
         @options ||= {}
       end
 
+      def returns(type)
+        @returns = type
+      end
+
+      def return_type
+        defined?(@returns) && @returns
+      end
+
+      def validate_return(value)
+        return_type && return_type[value]
+      end
+
       # Define an initializer value.
       # @param [Symbol] name of the argument
       def option(name, **kwargs)
         options[NameInterface[name]] = Parameter.new(name: name, **kwargs)
 
         define_method(name) { @context[name] }
         define_method("#{name}?") { !!@context[name] }
       end
 
       def call(context = {})
-        new(context: context).call
+        new(context: context).call.tap do |result|
+          validate_return(result)
+        end
       end
 
       def inject(injected)
-        Class.new(self) do
-          self.injected = injected
+        clone.tap do |clone|
+          clone.injected = injected
         end
       end
     end
 
     attr_reader :context
@@ -61,9 +93,19 @@
       @context = Context.new(self.class.injected).tap do |ctx|
         ctx.merge!(context.is_a?(Context) ? context.to_h : context)
       end
 
       Validator.call(options: self.class.options, context: @context)
+    end
+
+    # Pretty pretty printing.
+    def inspect
+      "#<#{self.class}:0x%x %s>" % [
+        object_id,
+        self.class.options.keys.map do |option|
+          "#{option}: #{context.send(option).inspect}"
+        end.join(' ')
+      ]
     end
 
     def call
       self
     end