feat: add the inline tag and json-style omitempty

Assisted-by: GLM 5.3 Flash

encode_test.go

@@ -2126,3 +2126,111 @@ func TestUnmarshalWithOptions(t *testing.T) {
 		}
 	})
 }
+
+func TestInlineTag(t *testing.T) {
+	type Inner struct {
+		A int `toml:"a"`
+		B int `toml:"b"`
+	}
+	t.Run("a struct field writes inline", func(t *testing.T) {
+		type Cfg struct {
+			Inner Inner `toml:"inner,inline"`
+		}
+		out, err := Marshal(Cfg{Inner: Inner{1, 2}})
+		if err != nil {
+			t.Fatal(err)
+		}
+		if string(out) != "inner = {a = 1, b = 2}\n" {
+			t.Errorf("output %q", out)
+		}
+	})
+	t.Run("a map field writes inline", func(t *testing.T) {
+		type Cfg struct {
+			Opts map[string]int `toml:"opts,inline"`
+		}
+		out, err := Marshal(Cfg{Opts: map[string]int{"x": 1}})
+		if err != nil {
+			t.Fatal(err)
+		}
+		if string(out) != "opts = {x = 1}\n" {
+			t.Errorf("output %q", out)
+		}
+	})
+	t.Run("a named embedded struct writes inline", func(t *testing.T) {
+		type Cfg struct {
+			Inner `toml:"inner,inline"`
+		}
+		out, err := Marshal(Cfg{Inner: Inner{1, 2}})
+		if err != nil {
+			t.Fatal(err)
+		}
+		if string(out) != "inner = {a = 1, b = 2}\n" {
+			t.Errorf("output %q", out)
+		}
+	})
+	t.Run("an inline field decodes back", func(t *testing.T) {
+		type Cfg struct {
+			Inner Inner `toml:"inner,inline"`
+		}
+		var cfg Cfg
+		if err := Unmarshal([]byte("inner = {a = 3, b = 4}\n"), &cfg); err != nil {
+			t.Fatal(err)
+		}
+		if cfg.Inner != (Inner{3, 4}) {
+			t.Errorf("decoded %+v", cfg.Inner)
+		}
+	})
+	t.Run("a forced inline of an array of tables is an error", func(t *testing.T) {
+		type Item struct {
+			N int `toml:"n"`
+		}
+		type Cfg struct {
+			Items []Item `toml:"items,inline"`
+		}
+		if _, err := Marshal(Cfg{Items: []Item{{1}}}); err == nil {
+			t.Error("forced inline of an array of tables succeeded, want an error")
+		}
+	})
+	t.Run("without the tag the header form stands", func(t *testing.T) {
+		type Cfg struct {
+			Inner Inner `toml:"inner"`
+		}
+		out, err := Marshal(Cfg{Inner: Inner{1, 2}})
+		if err != nil {
+			t.Fatal(err)
+		}
+		if string(out) != "[inner]\na = 1\nb = 2\n" {
+			t.Errorf("output %q", out)
+		}
+	})
+}
+
+func TestOmitEmptyJSONSemantics(t *testing.T) {
+	type Cfg struct {
+		Empty   string            `toml:"empty,omitempty"`
+		Full    string            `toml:"full,omitempty"`
+		Zero    int               `toml:"zero,omitempty"`
+		One     int               `toml:"one,omitempty"`
+		Off     bool              `toml:"off,omitempty"`
+		On      bool              `toml:"on,omitempty"`
+		Nil     *string           `toml:"nil,omitempty"`
+		Set     *string           `toml:"set,omitempty"`
+		Nothing map[string]string `toml:"nothing,omitempty"`
+		Somethg map[string]string `toml:"somethg,omitempty"`
+	}
+	s := "x"
+	out, err := Marshal(Cfg{
+		Full:    "y",
+		One:     1,
+		On:      true,
+		Set:     &s,
+		Somethg: map[string]string{"k": "v"},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := "full = \"y\"\none = 1\non = true\nset = \"x\"\n\n[somethg]\nk = \"v\"\n"
+	if string(out) != want {
+		t.Errorf("output:\n%q\nwant:\n%q", out, want)
+	}
+}