more tests, additional methods for fields

field.go

@@ -30,3 +30,17 @@ func (f *Field) IsEmbedded() bool {
 func (f *Field) IsExported() bool {
 	return f.field.PkgPath == ""
 }
+
+// IsZero returns true if the given field is not initalized (has a zero value).
+// It panics if the field is not exported.
+func (f *Field) IsZero() bool {
+	zero := reflect.Zero(f.value.Type()).Interface()
+	current := f.Value()
+
+	return reflect.DeepEqual(current, zero)
+}
+
+// Name returns the name of the given field
+func (f *Field) Name() string {
+	return f.field.Name
+}

field_test.go

@@ -8,6 +8,7 @@ type Foo struct {
 	B    int    `structure:"y"`
 	C    bool   `json:"c"`
 	d    string // not exported
+	x    string `xml:"x"` // not exported, with tag
 	*Bar        // embedded
 }
 
@@ -24,9 +25,9 @@ func newStruct() *Struct {
 		g: []string{"zeynep", "fatih"},
 	}
 
+	// B and x is not initialized for testing
 	f := &Foo{
 		A: "gopher",
-		B: 1,
 		C: true,
 		d: "small",
 	}
@@ -47,3 +48,56 @@ func TestField(t *testing.T) {
 
 	_ = s.Field("no-field")
 }
+
+func TestField_Tag(t *testing.T) {
+	s := newStruct()
+
+	v := s.Field("B").Tag("json")
+	if v != "" {
+		t.Errorf("Field's tag value of a non existing tag should return empty, got: %s", v)
+	}
+
+	v = s.Field("C").Tag("json")
+	if v != "c" {
+		t.Errorf("Field's tag value of the existing field C should return 'c', got: %s", v)
+	}
+
+	v = s.Field("d").Tag("json")
+	if v != "" {
+		t.Errorf("Field's tag value of a non exported field should return empty, got: %s", v)
+	}
+
+	v = s.Field("x").Tag("xml")
+	if v != "x" {
+		t.Errorf("Field's tag value of a non exported field with a tag should return 'x', got: %s", v)
+	}
+
+	v = s.Field("A").Tag("json")
+	if v != "" {
+		t.Errorf("Field's tag value of a existing field without a tag should return empty, got: %s", v)
+	}
+}
+
+func TestField_Value(t *testing.T) {
+	s := newStruct()
+
+	v := s.Field("A").Value()
+	val, ok := v.(string)
+	if !ok {
+		t.Errorf("Field's value of a A should be string")
+	}
+
+	if val != "gopher" {
+		t.Errorf("Field's value of a existing tag should return 'gopher', got: %s", val)
+	}
+
+	defer func() {
+		err := recover()
+		if err == nil {
+			t.Error("Value of a non exported field from the field should panic")
+		}
+	}()
+
+	// should panic
+	_ = s.Field("d").Value()
+}

structs.go

@@ -32,8 +32,7 @@ func (s *Struct) Fields() []string {
 }
 
 // Field returns a new Field struct that provides several high level functions
-// around a single struct field entitiy. It panics if the field is not found or
+// around a single struct field entitiy. It panics if the field is not found.
-// is unexported.
 func (s *Struct) Field(name string) *Field {
 	f, ok := s.FieldOk(name)
 	if !ok {
@@ -44,8 +43,8 @@ func (s *Struct) Field(name string) *Field {
 }
 
 // Field returns a new Field struct that provides several high level functions
-// around a single struct field entitiy and a boolean indicating if the field
+// around a single struct field entitiy. The boolean returns true if the field
-// was found. It panics if the or is unexported.
+// was found.
 func (s *Struct) FieldOk(name string) (*Field, bool) {
 	v := strctVal(s.raw)
 	t := v.Type()
@@ -55,10 +54,6 @@ func (s *Struct) FieldOk(name string) (*Field, bool) {
 		return nil, false
 	}
 
-	if field.PkgPath != "" {
-		panic("unexported field access is not allowed")
-	}
-
 	return &Field{
 		field: field,
 		value: v.FieldByName(name),