fix: add more Kleisli definitions

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

v2/reader/array.go

@@ -37,7 +37,7 @@ import (
 //	}
 //	r := reader.MonadTraverseArray(numbers, addPrefix)
 //	result := r(Config{Prefix: "num"}) // ["num1", "num2", "num3"]
-func MonadTraverseArray[R, A, B any](ma []A, f func(A) Reader[R, B]) Reader[R, []B] {
+func MonadTraverseArray[R, A, B any](ma []A, f Kleisli[R, A, B]) Reader[R, []B] {
 	return array.MonadTraverse[[]A](
 		Of[R, []B],
 		Map[R, []B, func(B) []B],
@@ -62,7 +62,7 @@ func MonadTraverseArray[R, A, B any](ma []A, f func(A) Reader[R, B]) Reader[R, [
 //	transform := reader.TraverseArray(multiply)
 //	r := transform([]int{1, 2, 3})
 //	result := r(Config{Multiplier: 10}) // [10, 20, 30]
-func TraverseArray[R, A, B any](f func(A) Reader[R, B]) func([]A) Reader[R, []B] {
+func TraverseArray[R, A, B any](f Kleisli[R, A, B]) func([]A) Reader[R, []B] {
 	return array.Traverse[[]A](
 		Of[R, []B],
 		Map[R, []B, func(B) []B],

v2/reader/bind.go

@@ -83,7 +83,7 @@ func Do[R, S any](
 //	)
 func Bind[R, S1, S2, T any](
 	setter func(T) func(S1) S2,
-	f func(S1) Reader[R, T],
+	f Kleisli[R, S1, T],
 ) Operator[R, S1, S2] {
 	return chain.Bind(
 		Chain[R, S1, S2],
@@ -283,7 +283,7 @@ func ApSL[R, S, T any](
 //	)
 func BindL[R, S, T any](
 	lens L.Lens[S, T],
-	f func(T) Reader[R, T],
+	f Kleisli[R, T, T],
 ) Operator[R, S, S] {
 	return Bind[R, S, S, T](lens.Set, func(s S) Reader[R, T] {
 		return f(lens.Get(s))

v2/reader/curry.go

@@ -48,7 +48,7 @@ func Curry0[R, A any](f func(R) A) Reader[R, A] {
 //	curried := reader.Curry1(addPrefix)
 //	r := curried("hello")
 //	result := r(Config{Prefix: ">> "}) // ">> hello"
-func Curry1[R, T1, A any](f func(R, T1) A) func(T1) Reader[R, A] {
+func Curry1[R, T1, A any](f func(R, T1) A) Kleisli[R, T1, A] {
 	return G.Curry1[Reader[R, A]](f)
 }
 
@@ -121,7 +121,7 @@ func Uncurry0[R, A any](f Reader[R, A]) func(R) A {
 //	}
 //	f := reader.Uncurry1(curried)
 //	result := f(Config{Prefix: ">> "}, "hello") // ">> hello"
-func Uncurry1[R, T1, A any](f func(T1) Reader[R, A]) func(R, T1) A {
+func Uncurry1[R, T1, A any](f Kleisli[R, T1, A]) func(R, T1) A {
 	return G.Uncurry1(f)
 }
 

v2/reader/reader.go

@@ -154,7 +154,7 @@ func Of[R, A any](a A) Reader[R, A] {
 //	}
 //	r := reader.MonadChain(getUser, getUserName)
 //	name := r(Config{UserId: 42}) // "User42"
-func MonadChain[R, A, B any](ma Reader[R, A], f func(A) Reader[R, B]) Reader[R, B] {
+func MonadChain[R, A, B any](ma Reader[R, A], f Kleisli[R, A, B]) Reader[R, B] {
 	return func(r R) B {
 		return f(ma(r))(r)
 	}
@@ -172,7 +172,7 @@ func MonadChain[R, A, B any](ma Reader[R, A], f func(A) Reader[R, B]) Reader[R,
 //	}
 //	r := reader.Chain(getUserName)(getUser)
 //	name := r(Config{UserId: 42}) // "User42"
-func Chain[R, A, B any](f func(A) Reader[R, B]) Operator[R, A, B] {
+func Chain[R, A, B any](f Kleisli[R, A, B]) Operator[R, A, B] {
 	return function.Bind2nd(MonadChain[R, A, B], f)
 }
 
@@ -187,7 +187,7 @@ func Chain[R, A, B any](f func(A) Reader[R, B]) Operator[R, A, B] {
 //	}
 //	flat := reader.Flatten(nested)
 //	result := flat(Config{Value: 5}) // 10 (5 + 5)
-func Flatten[R, A any](mma func(R) Reader[R, A]) Reader[R, A] {
+func Flatten[R, A any](mma Reader[R, Reader[R, A]]) Reader[R, A] {
 	return MonadChain(mma, function.Identity[Reader[R, A]])
 }
 

v2/reader/types.go

@@ -47,6 +47,8 @@ type (
 	//	apiKey := getAPIKey(config)      // "secret"
 	Reader[R, A any] = func(R) A
 
+	Kleisli[R, A, B any] = func(A) Reader[R, B]
+
 	// Operator represents a transformation from one Reader to another.
 	// It takes a Reader[R, A] and produces a Reader[R, B], where both readers
 	// share the same environment type R.
@@ -69,5 +71,5 @@ type (
 	//	getNumber := reader.Asks(func(c Config) int { return c.Multiplier })
 	//	getString := intToString(getNumber)
 	//	result := getString(Config{Multiplier: 42}) // "42"
-	Operator[R, A, B any] = func(Reader[R, A]) Reader[R, B]
+	Operator[R, A, B any] = Kleisli[R, Reader[R, A], B]
 )