fix: add writer

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

writer/generic/writer.go

@@ -0,0 +1,106 @@
+package generic
+
+import (
+	F "github.com/IBM/fp-go/function"
+	IO "github.com/IBM/fp-go/io/generic"
+	M "github.com/IBM/fp-go/monoid"
+	S "github.com/IBM/fp-go/semigroup"
+	T "github.com/IBM/fp-go/tuple"
+)
+
+func Of[GA ~func() T.Tuple2[A, W], W, A any](m M.Monoid[W]) func(A) GA {
+	return F.Flow2(
+		F.Bind2nd(T.MakeTuple2[A, W], m.Empty()),
+		IO.Of[GA],
+	)
+}
+
+func MonadMap[GB ~func() T.Tuple2[B, W], GA ~func() T.Tuple2[A, W], FCT ~func(A) B, W, A, B any](fa GA, f FCT) GB {
+	return IO.MonadMap[GA, GB](fa, T.Map2(f, F.Identity[W]))
+}
+
+func Map[GB ~func() T.Tuple2[B, W], GA ~func() T.Tuple2[A, W], FCT ~func(A) B, W, A, B any](f FCT) func(GA) GB {
+	return IO.Map[GA, GB](T.Map2(f, F.Identity[W]))
+}
+
+func MonadChain[GB ~func() T.Tuple2[B, W], GA ~func() T.Tuple2[A, W], FCT ~func(A) GB, W, A, B any](s S.Semigroup[W]) func(GA, FCT) GB {
+	return func(fa GA, f FCT) GB {
+
+		return func() T.Tuple2[B, W] {
+			a := fa()
+			b := f(a.F1)()
+
+			return T.MakeTuple2(b.F1, s.Concat(a.F2, b.F2))
+		}
+	}
+}
+
+func Chain[GB ~func() T.Tuple2[B, W], GA ~func() T.Tuple2[A, W], FCT ~func(A) GB, W, A, B any](s S.Semigroup[W]) func(FCT) func(GA) GB {
+	return F.Curry2(F.Swap(MonadChain[GB, GA, FCT](s)))
+}
+
+func MonadAp[GB ~func() T.Tuple2[B, W], GAB ~func() T.Tuple2[func(A) B, W], GA ~func() T.Tuple2[A, W], W, A, B any](s S.Semigroup[W]) func(GAB, GA) GB {
+	return func(fab GAB, fa GA) GB {
+		return func() T.Tuple2[B, W] {
+			f := fab()
+			a := fa()
+
+			return T.MakeTuple2(f.F1(a.F1), s.Concat(f.F2, a.F2))
+		}
+	}
+}
+
+func Ap[GB ~func() T.Tuple2[B, W], GAB ~func() T.Tuple2[func(A) B, W], GA ~func() T.Tuple2[A, W], W, A, B any](s S.Semigroup[W]) func(GA) func(GAB) GB {
+	return F.Curry2(F.Swap(MonadAp[GB, GAB, GA](s)))
+}
+
+func MonadChainFirst[GB ~func() T.Tuple2[B, W], GA ~func() T.Tuple2[A, W], FCT ~func(A) GB, W, A, B any](s S.Semigroup[W]) func(GA, FCT) GA {
+	chain := MonadChain[GA, GA, func(A) GA](s)
+	return func(ma GA, f FCT) GA {
+		return chain(ma, func(a A) GA {
+			return MonadMap[GA](f(a), F.Constant1[B](a))
+		})
+	}
+}
+
+func ChainFirst[GB ~func() T.Tuple2[B, W], GA ~func() T.Tuple2[A, W], FCT ~func(A) GB, W, A, B any](s S.Semigroup[W]) func(FCT) func(GA) GA {
+	return F.Curry2(F.Swap(MonadChainFirst[GB, GA, FCT](s)))
+}
+
+func Flatten[GAA ~func() T.Tuple2[GA, W], GA ~func() T.Tuple2[A, W], W, A any](s S.Semigroup[W]) func(GAA) GA {
+	chain := MonadChain[GA, GAA, func(GA) GA](s)
+	return func(mma GAA) GA {
+		return chain(mma, F.Identity[GA])
+	}
+}
+
+func Execute[GA ~func() T.Tuple2[A, W], W, A any](fa GA) W {
+	return T.Second(fa())
+}
+
+func Evaluate[GA ~func() T.Tuple2[A, W], W, A any](fa GA) A {
+	return T.First(fa())
+}
+
+// MonadCensor modifies the final accumulator value by applying a function
+func MonadCensor[GA ~func() T.Tuple2[A, W], FCT ~func(W) W, W, A any](fa GA, f FCT) GA {
+	return IO.MonadMap[GA, GA](fa, T.Map2(F.Identity[A], f))
+}
+
+// Censor modifies the final accumulator value by applying a function
+func Censor[GA ~func() T.Tuple2[A, W], FCT ~func(W) W, W, A any](f FCT) func(GA) GA {
+	return IO.Map[GA, GA](T.Map2(F.Identity[A], f))
+}
+
+// MonadListens projects a value from modifications made to the accumulator during an action
+func MonadListens[GA ~func() T.Tuple2[A, W], GAB ~func() T.Tuple2[T.Tuple2[A, B], W], FCT ~func(W) B, W, A, B any](fa GA, f FCT) GAB {
+	return func() T.Tuple2[T.Tuple2[A, B], W] {
+		a := fa()
+		return T.MakeTuple2(T.MakeTuple2(a.F1, f(a.F2)), a.F2)
+	}
+}
+
+// Listens projects a value from modifications made to the accumulator during an action
+func Listens[GA ~func() T.Tuple2[A, W], GAB ~func() T.Tuple2[T.Tuple2[A, B], W], FCT ~func(W) B, W, A, B any](f FCT) func(GA) GAB {
+	return F.Bind2nd(MonadListens[GA, GAB, FCT], f)
+}