feat: support pointer values

.github/workflows/lint-test.yml

@@ -0,0 +1,46 @@
+name: Lint and Test
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches:
+      - master
+      - feature/*
+      - bugfix/*
+      - patch/*
+      - refactor/*
+      - chore/*
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0 # needed because of the new-from-rev in golangci
+
+      - name: Set up Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: "1.23"
+
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v3
+        with:
+          args: --timeout 5m0s
+
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v3
+
+      - name: Set up Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: "1.23"
+
+      - name: Running Unit Tests
+        run: go test ./...

marshal_test.go

@@ -12,6 +12,11 @@ import (
 )
 
 func TestMarshal(t *testing.T) {
+	t.Run("success", testMarshalSuccess)
+	t.Run("success pointer", testMarshalSuccessPointer)
+}
+
+func testMarshalSuccess(t *testing.T) {
 	expected, err := testdata.ReadFile("testdata/marshal/success.csv")
 	if err != nil {
 		t.Fatalf("read test file: %v", err)
@@ -54,3 +59,47 @@ func TestMarshal(t *testing.T) {
 		t.Errorf("(-expected, +got):\n%s", diff)
 	}
 }
+
+func testMarshalSuccessPointer(t *testing.T) {
+	expected, err := testdata.ReadFile("testdata/marshal/success.csv")
+	if err != nil {
+		t.Fatalf("read test file: %v", err)
+	}
+
+	type record struct {
+		FirstName string  `flat:"first_name"`
+		LastName  string  `flat:"last_name"`
+		Ignore    uint8   `flat:"-"`
+		Age       int     `flat:"age"`
+		Height    float32 `flat:"height"`
+	}
+
+	input := []*record{
+		{
+			FirstName: "John",
+			LastName:  "Doe",
+			Ignore:    123,
+			Age:       30,
+			Height:    1.75,
+		},
+		{
+			FirstName: "Jane",
+			LastName:  "Doe",
+			Ignore:    123,
+			Age:       25,
+			Height:    1.65,
+		},
+	}
+	var got bytes.Buffer
+
+	writer := csv.NewWriter(&got)
+
+	err = goflat.MarshalSliceToWriter(context.Background(), input, writer, goflat.Options{})
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+
+	if diff := cmp.Diff(string(expected), got.String()); diff != "" {
+		t.Errorf("(-expected, +got):\n%s", diff)
+	}
+}

reflect.go

@@ -9,6 +9,7 @@ import (
 
 type structFactory[T any] struct {
 	structType   reflect.Type
+	pointer      bool
 	columnMap    map[int]int
 	columnValues []any
 	columnNames  []string
@@ -18,31 +19,36 @@ type structFactory[T any] struct {
 // work with them.
 const FieldTag = "flat"
 
-//nolint:varnamelen // Fine-ish here.
+//nolint:varnamelen,cyclop // Fine-ish here.
 func newFactory[T any](headers []string, options Options) (*structFactory[T], error) {
 	var v T
 
 	t := reflect.TypeOf(v)
+	rv := reflect.ValueOf(v)
 
-	if t.Kind() == reflect.Pointer {
-		t = t.Elem()
-	}
+	pointer := false
 
-	if t.Kind() != reflect.Struct {
+	//nolint:exhaustive // Fine here, there's a default.
+	switch t.Kind() {
+	case reflect.Struct:
+	case reflect.Pointer:
+		pointer = true
+		t = t.Elem()
+		rv = reflect.New(t).Elem()
+	default:
 		return nil, fmt.Errorf("type %T: %w", v, ErrNotAStruct)
 	}
 
 	factory := &structFactory[T]{
 		structType:   t,
+		pointer:      pointer,
 		columnMap:    make(map[int]int, len(headers)),
 		columnValues: make([]any, t.NumField()),
 		columnNames:  make([]string, t.NumField()),
 	}
 
 	covered := make([]bool, len(headers))
 
-	rv := reflect.ValueOf(v)
-
 	for i := range t.NumField() {
 		fieldT := t.Field(i)
 		fieldV := rv.Field(i)
@@ -163,6 +169,10 @@ func (s *structFactory[T]) unmarshal(record []string) (T, error) {
 		newStruct.Field(mappedIndex).Set(reflect.ValueOf(value))
 	}
 
+	if s.pointer {
+		newStruct = newStruct.Addr()
+	}
+
 	return newStruct.Interface().(T), nil
 }
 
@@ -183,6 +193,10 @@ func (s *structFactory[T]) marshalHeaders() []string {
 func (s *structFactory[T]) marshal(t T, separator string) ([]string, error) {
 	reflectValue := reflect.ValueOf(t)
 
+	if s.pointer {
+		reflectValue = reflectValue.Elem()
+	}
+
 	record := make([]string, 0, len(s.columnNames))
 
 	var strValue string

reflect_internal_test.go

@@ -82,6 +82,7 @@ func testReflectSuccess(t *testing.T) {
 	t.Run("duplicate", testReflectSuccessDuplicate)
 	t.Run("simple", testReflectSuccessSimple)
 	t.Run("subset struct", testReflectSuccessSubsetStruct)
+	t.Run("pointer", testReflectSuccessPointer)
 }
 
 func testReflectSuccessDuplicate(t *testing.T) {
@@ -209,3 +210,43 @@ func testReflectSuccessSubsetStruct(t *testing.T) {
 		t.Errorf("(-want +got):\\n%s", diff)
 	}
 }
+
+func testReflectSuccessPointer(t *testing.T) {
+	type foo struct {
+		Name string `flat:"name"`
+	}
+
+	headers := []string{"name"}
+
+	got, err := newFactory[*foo](headers, Options{
+		Strict:                  true,
+		ErrorIfDuplicateHeaders: true,
+		ErrorIfMissingHeaders:   true,
+	})
+	if err != nil {
+		t.Errorf("expected no error, got %v", err)
+	}
+
+	expected := &structFactory[*foo]{
+		structType: reflect.TypeOf(foo{}),
+		columnMap:  map[int]int{0: 0},
+	}
+	comparers := []cmp.Option{
+		cmp.AllowUnexported(structFactory[*foo]{}),
+		cmp.Comparer(func(a, b structFactory[*foo]) bool {
+			if a.structType.String() != b.structType.String() {
+				return false
+			}
+
+			if !maps.Equal(a.columnMap, b.columnMap) {
+				return false
+			}
+
+			return true
+		}),
+	}
+
+	if diff := cmp.Diff(expected, got, comparers...); diff != "" {
+		t.Errorf("(-want +got):\\n%s", diff)
+	}
+}

unmarshal_test.go

@@ -13,6 +13,7 @@ import (
 
 func TestUnmarshal(t *testing.T) {
 	t.Run("success", testUnmarshalSuccess)
+	t.Run("success pointer", testUnmarshalSuccessPointer)
 }
 
 //go:embed testdata
@@ -53,7 +54,7 @@ func testUnmarshalSuccess(t *testing.T) {
 	}
 
 	channel := make(chan record)
-	assertChannel(t, channel, expected)
+	assertChannel(t, channel, expected, cmp.AllowUnexported(record{}))
 
 	ctx := context.Background()
 
@@ -74,7 +75,63 @@ func testUnmarshalSuccess(t *testing.T) {
 	}
 }
 
-func assertChannel[T any](t *testing.T, ch <-chan T, expected []T) {
+func testUnmarshalSuccessPointer(t *testing.T) {
+	file, err := testdata.Open("testdata/unmarshal/success.csv")
+	if err != nil {
+		t.Fatalf("open test file: %v", err)
+	}
+
+	type record struct {
+		FirstName string  `flat:"first_name"`
+		LastName  string  `flat:"last_name"`
+		Age       int     `flat:"age"`
+		Height    float32 `flat:"height"`
+	}
+
+	expected := []*record{
+		{
+			FirstName: "Guybrush",
+			LastName:  "Threepwood",
+			Age:       28,
+			Height:    1.78,
+		},
+		{
+			FirstName: "Elaine",
+			LastName:  "Marley",
+			Age:       20,
+			Height:    1.6,
+		},
+		{
+			FirstName: "LeChuck",
+			LastName:  "",
+			Age:       100,
+			Height:    2.01,
+		},
+	}
+
+	channel := make(chan *record)
+	assertChannel(t, channel, expected, cmp.AllowUnexported(record{}))
+
+	ctx := context.Background()
+
+	csvReader, err := goflat.DetectReader(file)
+	if err != nil {
+		t.Fatalf("detect reader: %v", err)
+	}
+
+	options := goflat.Options{
+		Strict:                  true,
+		ErrorIfDuplicateHeaders: true,
+		ErrorIfMissingHeaders:   true,
+	}
+
+	err = goflat.UnmarshalToChannel(ctx, csvReader, options, channel)
+	if err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+}
+
+func assertChannel[T any](t *testing.T, ch <-chan T, expected []T, cmpOpts ...cmp.Option) {
 	t.Helper()
 
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
@@ -98,11 +155,9 @@ func assertChannel[T any](t *testing.T, ch <-chan T, expected []T) {
 	}()
 
 	t.Cleanup(func() {
-		var zero T
-
 		<-ctx.Done()
 
-		if diff := cmp.Diff(expected, got, cmp.AllowUnexported(zero)); diff != "" {
+		if diff := cmp.Diff(expected, got, cmpOpts...); diff != "" {
 			t.Errorf("(-expected,+got):\n%s", diff)
 		}
 	})