fix: add optics and consistent copyright

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

optics/optional/record/generic/generic.go

@@ -0,0 +1,37 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package generic
+
+import (
+	OP "github.com/IBM/fp-go/optics/optional"
+	O "github.com/IBM/fp-go/option"
+	RR "github.com/IBM/fp-go/record/generic"
+)
+
+func setter[M ~map[K]V, K comparable, V any](key K) func(M, V) M {
+	return func(dst M, value V) M {
+		return RR.UpsertAt[M](key, value)(dst)
+	}
+}
+
+func getter[M ~map[K]V, K comparable, V any](key K) func(M) O.Option[V] {
+	return RR.Lookup[M](key)
+}
+
+// AtKey returns a Optional that gets and sets properties of a map
+func AtKey[M ~map[K]V, K comparable, V any](key K) OP.Optional[M, V] {
+	return OP.MakeOptional(getter[M](key), setter[M](key))
+}

optics/optional/record/record.go

@@ -0,0 +1,26 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package record
+
+import (
+	OP "github.com/IBM/fp-go/optics/optional"
+	G "github.com/IBM/fp-go/optics/optional/record/generic"
+)
+
+// FromProperty returns a Optional that gets and sets properties of a map
+func AtKey[K comparable, V any](key K) OP.Optional[map[K]V, V] {
+	return G.AtKey[map[K]V](key)
+}

optics/optional/record/record_test.go

@@ -0,0 +1,100 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package record
+
+import (
+	"testing"
+
+	F "github.com/IBM/fp-go/function"
+	OP "github.com/IBM/fp-go/optics/optional"
+	O "github.com/IBM/fp-go/option"
+	ON "github.com/IBM/fp-go/option/number"
+	RR "github.com/IBM/fp-go/record"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type (
+	GenericMap = map[string]any
+)
+
+func TestOptionalRecord(t *testing.T) {
+	// sample record
+	r := RR.Singleton("key", "value")
+
+	// extract values
+	optKey := AtKey[string, string]("key")
+	optKey1 := AtKey[string, string]("key1")
+
+	// check if we can get the key
+	assert.Equal(t, O.Of("value"), optKey.GetOption(r))
+	assert.Equal(t, O.None[string](), optKey1.GetOption(r))
+
+	// check if we can set a value
+	r1 := optKey1.Set("value1")(r)
+
+	// check if we can get the key
+	assert.Equal(t, O.Of("value"), optKey.GetOption(r))
+	assert.Equal(t, O.None[string](), optKey1.GetOption(r))
+	// check if we can get the key
+	assert.Equal(t, O.Of("value"), optKey.GetOption(r1))
+	assert.Equal(t, O.Of("value1"), optKey1.GetOption(r1))
+}
+
+func TestOptionalWithType(t *testing.T) {
+	// sample record
+	r := RR.Singleton("key", "1")
+	// convert between string and int
+	// writes a key
+	optStringKey := AtKey[string, string]("key")
+	optIntKey := F.Pipe1(
+		optStringKey,
+		OP.IChain[map[string]string](ON.Atoi, ON.Itoa),
+	)
+	// test the scenarions
+	assert.Equal(t, O.Of("1"), optStringKey.GetOption(r))
+	assert.Equal(t, O.Of(1), optIntKey.GetOption(r))
+	// modify
+	r1 := optIntKey.Set(2)(r)
+	assert.Equal(t, O.Of("2"), optStringKey.GetOption(r1))
+	assert.Equal(t, O.Of(2), optIntKey.GetOption(r1))
+}
+
+// func TestNestedRecord(t *testing.T) {
+// 	// some sample data
+// 	x := GenericMap{
+// 		"a": GenericMap{
+// 			"b": "1",
+// 		},
+// 	}
+// 	// accessor for first level
+// 	optA := F.Pipe1(
+// 		AtKey[string, any]("a"),
+// 		OP.IChainAny[GenericMap, GenericMap](),
+// 	)
+// 	optB := F.Pipe2(
+// 		AtKey[string, any]("b"),
+// 		OP.IChainAny[GenericMap, string](),
+// 		OP.IChain[GenericMap](ON.Atoi, ON.Itoa),
+// 	)
+// 	// go directly to b
+// 	optAB := F.Pipe1(
+// 		optA,
+// 		OP.Compose[GenericMap](optB),
+// 	)
+// 	// access the value of b
+// 	assert.Equal(t, O.Of(1), optAB.GetOption(x))
+// }