fix: add more mostly-adequate examples and solutions

Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>

samples/mostly-adequate/chapter10_applicativefunctor_test.go

@@ -23,16 +23,65 @@ import (
 	R "github.com/IBM/fp-go/context/readerioeither"
 	H "github.com/IBM/fp-go/context/readerioeither/http"
 	F "github.com/IBM/fp-go/function"
+	IOO "github.com/IBM/fp-go/iooption"
+	N "github.com/IBM/fp-go/number"
+	O "github.com/IBM/fp-go/option"
+	M "github.com/IBM/fp-go/record"
+	T "github.com/IBM/fp-go/tuple"
 )
 
-type PostItem struct {
-	UserId uint   `json:"userId"`
-	Id     uint   `json:"id"`
-	Title  string `json:"title"`
-	Body   string `json:"body"`
+type (
+	PostItem struct {
+		UserId uint   `json:"userId"`
+		Id     uint   `json:"id"`
+		Title  string `json:"title"`
+		Body   string `json:"body"`
+	}
+
+	Player struct {
+		Id   int
+		Name string
+	}
+
+	LocalStorage = map[string]Player
+)
+
+var (
+	playerAlbert = Player{
+		Id:   1,
+		Name: "Albert",
+	}
+	playerTheresa = Player{
+		Id:   2,
+		Name: "Theresa",
+	}
+	localStorage = LocalStorage{
+		"player1": playerAlbert,
+		"player2": playerTheresa,
+	}
+
+	// getFromCache :: String -> IO User
+	getFromCache = func(name string) IOO.IOOption[Player] {
+		return func() O.Option[Player] {
+			return M.MonadLookup(localStorage, name)
+		}
+	}
+
+	// game :: User -> User -> String
+	game = F.Curry2(func(a, b Player) string {
+		return fmt.Sprintf("%s vs %s", a.Name, b.Name)
+	})
+)
+
+func (player Player) getName() string {
+	return player.Name
 }
 
-func getTitle(item PostItem) string {
+func (player Player) getId() int {
+	return player.Id
+}
+
+func (item PostItem) getTitle() string {
 	return item.Title
 }
 
@@ -55,7 +104,7 @@ func Example_renderPage() {
 		idxToUrl,
 		H.MakeGetRequest,
 		H.ReadJson[PostItem](client),
-		R.Map(getTitle),
+		R.Map(PostItem.getTitle),
 	)
 
 	res := F.Pipe2(
@@ -71,3 +120,64 @@ func Example_renderPage() {
 	// Right[<nil>, string](<div>Destinations: [qui est esse], Events: [ea molestias quasi exercitationem repellat qui ipsa sit aut]</div>)
 
 }
+
+func Example_solution10A() {
+	safeAdd := F.Curry2(func(a, b O.Option[int]) O.Option[int] {
+		return F.Pipe3(
+			N.Add[int],
+			O.Of[func(int) func(int) int],
+			O.Ap[func(int) int](a),
+			O.Ap[int](b),
+		)
+	})
+
+	fmt.Println(safeAdd(O.Of(2))(O.Of(3)))
+	fmt.Println(safeAdd(O.None[int]())(O.Of(3)))
+	fmt.Println(safeAdd(O.Of(2))(O.None[int]()))
+
+	// Output:
+	// Some[int](5)
+	// None[int]
+	// None[int]
+}
+
+func Example_solution10B() {
+
+	safeAdd := F.Curry2(T.Untupled2(F.Flow2(
+		O.SequenceTuple2[int, int],
+		O.Map(T.Tupled2(N.MonoidSum[int]().Concat)),
+	)))
+
+	fmt.Println(safeAdd(O.Of(2))(O.Of(3)))
+	fmt.Println(safeAdd(O.None[int]())(O.Of(3)))
+	fmt.Println(safeAdd(O.Of(2))(O.None[int]()))
+
+	// Output:
+	// Some[int](5)
+	// None[int]
+	// None[int]
+}
+
+func Example_solution10C() {
+	// startGame :: IO String
+	startGame := F.Pipe2(
+		IOO.Of(game),
+		IOO.Ap[func(Player) string](getFromCache("player1")),
+		IOO.Ap[string](getFromCache("player2")),
+	)
+
+	startGameTupled := F.Pipe2(
+		T.MakeTuple2("player1", "player2"),
+		IOO.TraverseTuple2(getFromCache, getFromCache),
+		IOO.Map(T.Tupled2(func(a, b Player) string {
+			return fmt.Sprintf("%s vs %s", a.Name, b.Name)
+		})),
+	)
+
+	fmt.Println(startGame())
+	fmt.Println(startGameTupled())
+
+	// Output:
+	// Some[string](Albert vs Theresa)
+	// Some[string](Albert vs Theresa)
+}