wip

filter.go

@@ -0,0 +1,12 @@
+package lambda
+
+func Filter[T any](xs []T, fx func(T) bool) []T {
+	n := 0
+	for _, x := range xs {
+		if fx(x) {
+			xs[n] = x
+			n++
+		}
+	}
+	return xs[:n]
+}

fold.go

@@ -0,0 +1,9 @@
+package lambda
+
+func Foldl[T any](xs []T, fx func(T, T) T) T {
+	return *new(T)
+}
+
+func Foldr[T any](xs []T, fx func(T, T) T) T {
+	return *new(T)
+}

go.mod

@@ -0,0 +1,3 @@
+module git.tuxpa.in/a/lambda
+
+go 1.18

map.go

@@ -0,0 +1,33 @@
+package lambda
+
+func Map[T any](xs []T, fx func(T) T) []T {
+	for i, v := range xs {
+		xs[i] = fx(v)
+	}
+	return xs
+}
+
+func MapV[T, V any](xs []T, fx func(T) V) (ov []V) {
+	ov = make([]V, len(xs))
+	for i, v := range xs {
+		ov[i] = fx(v)
+	}
+	return
+}
+
+func MapError[T any](xs []T, fx func(T) (T, error)) (ov []T, oe []error) {
+	oe = make([]error, len(xs))
+	for i, v := range xs {
+		xs[i], oe[i] = fx(v)
+	}
+	return
+}
+
+func MapErrorV[T, V any](xs []T, fx func(T) (V, error)) (ov []V, oe []error) {
+	ov = make([]V, len(xs))
+	oe = make([]error, len(xs))
+	for i, v := range xs {
+		ov[i], oe[i] = fx(v)
+	}
+	return
+}