Merge pull request #111 from dry-rb/add-deconstruct-keys

Add support for deconstruct_keys

Author: flash-gordon

lib/dry/monads/right_biased.rb

@@ -191,6 +191,7 @@ def and(mb)
         #   in Success(2..100) then ...
         #   in Success(2..200 => code) then ...
         #   end
+        #
         # @api private
         def deconstruct
           if Unit.equal?(@value)
@@ -202,6 +203,25 @@ def deconstruct
           end
         end
 
+        # Pattern matching hash values
+        #
+        # @example
+        #   case Success(x)
+        #   in Success(code: 200...300) then :ok
+        #   in Success(code: 300...400) then :redirect
+        #   in Success(code: 400...500) then :user_error
+        #   in Success(code: 500...600) then :server_error
+        #   end
+        #
+        # @api private
+        def deconstruct_keys(_)
+          if @value.is_a?(::Hash)
+            @value
+          else
+            EMPTY_HASH
+          end
+        end
+
         private
 
         # @api private
@@ -340,6 +360,23 @@ def deconstruct
             [@value]
           end
         end
+
+        # Pattern matching hash values
+        #
+        # @example
+        #   case Failure(x)
+        #   in Failure(code: 400...500) then :user_error
+        #   in Failure(code: 500...600) then :server_error
+        #   end
+        #
+        # @api private
+        def deconstruct_keys(_)
+          if @value.is_a?(::Hash)
+            @value
+          else
+            EMPTY_HASH
+          end
+        end
       end
     end
   end

spec/integration/pattern_matching_spec.rb

@@ -19,6 +19,7 @@ def call(value)
             in Success(:code, x) then x
             in Success[:status, x] then x
             in Success({ status: x }) then x
+            in Success(code: 301 | 302) then :redirect
             in Success({ code: 200..300 => x }) then x
             end
           end
@@ -32,6 +33,10 @@ def call(value)
         expect(match.(Success([:status, 600]))).to eql(600)
         expect(match.(Success({ status: 404 }))).to eql(404)
         expect(match.(Success({ code: 204 }))).to eql(204)
+        expect(match.(Success(code: 301))).to eql(:redirect)
+        expect(match.(Success(code: 302))).to eql(:redirect)
+        expect { match.(Success(code: 303)) }.to raise_error(NoMatchingPatternError)
+        expect { match.(Success([:foo])) }.to raise_error(NoMatchingPatternError)
       end
     end
 
@@ -46,6 +51,7 @@ def call(value)
             case value
             in Failure[:not_found, reason] then reason
             in Failure(:error) then :nope
+            in Failure(error: code) then code
             in Failure() then :unit
             end
           end
@@ -54,6 +60,7 @@ def call(value)
         expect(match.(Failure([:not_found, :no]))).to eql(:no)
         expect(match.(Failure(:error))).to eql(:nope)
         expect(match.(Failure())).to eql(:unit)
+        expect(match.(Failure(error: :bug))).to eql(:bug)
         expect { match.(Failure(3)) }.to raise_error(NoMatchingPatternError)
       end
     end