refactor: rename the encoder layout options

Assisted-by: GLM 5.3 Flash

CHANGELOG.md

@@ -125,6 +125,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- `Encoder.GroupByKind(bool)` is renamed to `Encoder.Layout(kind)` and takes
+  a `LayoutKind`: `LayoutKindGrouped`, the default, or
+  `LayoutKindDeclaration` for the declaration order. `UseLiteralMultiline`
+  is renamed to `LiteralMultiline`. The behaviour is unchanged; 2.0 is the
+  only chance a rename has, and the migrator updates the calls mechanically.
 - `DecodeError` and `EncodeError` carry one `Path` type, a list of segments
   (`"items"`, `"[0]"`, `"weight"`) with a `String()` rendering the TOML
   notation, `items[0].weight`. The decode error used to hold a bare

README.md

@@ -131,9 +131,9 @@ The value `MarshalTOML` returns is encoded in place of the receiver;
 
 ```go
 out, err := interpres.NewEncoder().
-	GroupByKind(false).      // preserve declaration order
+	Layout(interpres.LayoutKindDeclaration), // preserve declaration order
 	OmitEmptyArrays().       // skip empty scalar arrays
-	UseLiteralMultiline(80). // long multi-line strings as literal blocks
+	LiteralMultiline(80),       // long multi-line strings as literal blocks
 	Marshal(cfg)
 ```
 

docs/API.md

@@ -555,11 +555,11 @@ parsed as keys of the sub-table.
 
 ### Preserving declaration order
 
-`GroupByKind(false)` on an `Encoder` walks the entries in declaration order
+`LayoutKindDeclaration` on an `Encoder` walks the entries in declaration order
 instead, emitting each header immediately before its content:
 
 ```go
-out, err := interpres.NewEncoder().GroupByKind(false).Marshal(cfg)
+out, err := interpres.NewEncoder().Layout(interpres.LayoutKindDeclaration).Marshal(cfg)
 ```
 
 The output remains parseable, but a scalar declared after a sub-table lands
@@ -650,12 +650,12 @@ omitted, because TOML forbids an empty `[[a]]`. Other empty arrays emit as
 ### Long strings
 
 By default every string is emitted as a basic `"..."` string with the escapes
-TOML requires, a newline among them as `\n`. `UseLiteralMultiline(threshold)`
+TOML requires, a newline among them as `\n`. `LiteralMultiline(threshold)`
 switches strings that contain a newline and are at least `threshold` bytes long
 to the literal `'''...'''` form, which carries the newlines verbatim:
 
 ```go
-out, err := interpres.NewEncoder().UseLiteralMultiline(80).Marshal(cfg)
+out, err := interpres.NewEncoder().LiteralMultiline(80).Marshal(cfg)
 ```
 
 Single-line strings keep the basic form regardless of the threshold, and a
@@ -826,17 +826,17 @@ encoder:
 
 | Method | Default | Effect |
 |---|---|---|
-| `GroupByKind(v bool)` | `true` | group entries as scalars, then sub-tables, then arrays of tables; `false` preserves declaration order |
+| `Layout(kind LayoutKind)` | `LayoutKindGrouped` | group entries as scalars, then sub-tables, then arrays of tables; `LayoutKindDeclaration` preserves declaration order |
 | `OmitEmptyArrays()` | off | skip `key = []` for empty scalar arrays |
-| `UseLiteralMultiline(threshold int)` | `0` | emit multi-line strings of at least `threshold` bytes as literal `'''...'''` |
+| `LiteralMultiline(threshold int)` | `0` | emit multi-line strings of at least `threshold` bytes as literal `'''...'''` |
 | `InlineTables(threshold int)` | `0` | write a sub-table inline when its single-line form is at most `threshold` bytes |
 | `EmitFieldComments()` | off | print the `comment=` tag option of a field above its line or header |
 
 ```go
 out, err := interpres.NewEncoder().
-	GroupByKind(false).
+	Layout(interpres.LayoutKindDeclaration).
 	OmitEmptyArrays().
-	UseLiteralMultiline(80).
+	LiteralMultiline(80).
 	InlineTables(60).
 	MarshalContext(ctx, cfg)
 ```

docs/ARCHITECTURE.md

@@ -77,7 +77,7 @@ sequenceDiagram
 ```
 
 Encoding walks the other way. `encode.go` first builds a `tomlDoc` from the
-value, then emits it; the two phases are why `GroupByKind` can reorder entries
+value, then emits it; the two phases are why `Layout` can reorder entries
 without a second reflection pass, and why cancellation is checked during both.
 
 ```mermaid

encode.go

@@ -295,7 +295,7 @@ const (
 
 // entry is one binding in a tomlDoc. entries live in a single slice in the
 // order they were added; emission walks that order directly, either as it is
-// (Encoder with GroupByKind(false)) or in kind-grouped passes over the same
+// (Encoder with LayoutKindDeclaration) or in kind-grouped passes over the same
 // slice (the default).
 type entry struct {
 	kind entryKind
@@ -1157,7 +1157,7 @@ func (e *encoder) writeBlankLine() {
 }
 
 func (e *encoder) emitDoc(doc *tomlDoc, prefix []string) error {
-	if e.opts.groupByKind {
+	if e.opts.layout == LayoutKindGrouped {
 		// Scalars first, then inline sub-tables as value lines, then the
 		// remaining tables as headers, then arrays of tables. Each pass walks
 		// the entries in place; grouping copies of them cost the encoder a

encode_test.go

@@ -96,8 +96,8 @@ func TestMarshalContextHonoursCancellation(t *testing.T) {
 	}
 }
 
-func TestEncoderGroupByKindDefault(t *testing.T) {
-	// NewEncoder must default to GroupByKind=true so legacy callers keep the
+func TestEncoderLayoutGroupedDefault(t *testing.T) {
+	// NewEncoder must default to LayoutKindGrouped so legacy callers keep the
 	// scalars-first ordering.
 	type Cfg struct {
 		Name string `toml:"name"`
@@ -117,7 +117,7 @@ func TestEncoderGroupByKindDefault(t *testing.T) {
 	}
 }
 
-func TestEncoderGroupByKindFalsePreservesOrder(t *testing.T) {
+func TestEncoderLayoutDeclarationPreservesOrder(t *testing.T) {
 	type Inner struct {
 		Host string `toml:"host"`
 	}
@@ -131,11 +131,11 @@ func TestEncoderGroupByKindFalsePreservesOrder(t *testing.T) {
 		Server: Inner{Host: "h"},
 		Debug:  true,
 	}
-	out, err := NewEncoder().GroupByKind(false).Marshal(in)
+	out, err := NewEncoder().Layout(LayoutKindDeclaration).Marshal(in)
 	if err != nil {
 		t.Fatalf("marshal: %v", err)
 	}
-	// With GroupByKind(false) the encoder walks entries in declaration order.
+	// With Layout(LayoutKindDeclaration) the encoder walks entries in declaration order.
 	// The output is still parseable, but a scalar that follows a header is
 	// parsed as a sub-table key. That is the user's trade-off; see
 	// docs/API.md.
@@ -145,8 +145,8 @@ func TestEncoderGroupByKindFalsePreservesOrder(t *testing.T) {
 	}
 }
 
-func TestEncoderGroupByKindTrueDefaultOrder(t *testing.T) {
-	// The default (GroupByKind=true) must lift the trailing scalar ahead of
+func TestEncoderLayoutGroupedDefaultOrder(t *testing.T) {
+	// The default (LayoutKindGrouped) must lift the trailing scalar ahead of
 	// the [server] block so the document round-trips losslessly.
 	type Inner struct {
 		Host string `toml:"host"`
@@ -224,12 +224,12 @@ func TestEncoderOmitEmptyArrayOfTablesStillSkipped(t *testing.T) {
 	}
 }
 
-func TestEncoderUseLiteralMultiline(t *testing.T) {
+func TestEncoderLiteralMultiline(t *testing.T) {
 	type Cfg struct {
 		Long string `toml:"long"`
 	}
 	long := strings.Repeat("a", 50) + "\nline two\nline three"
-	out, err := NewEncoder().UseLiteralMultiline(20).Marshal(Cfg{Long: long})
+	out, err := NewEncoder().LiteralMultiline(20).Marshal(Cfg{Long: long})
 	if err != nil {
 		t.Fatalf("marshal: %v", err)
 	}
@@ -239,12 +239,12 @@ func TestEncoderUseLiteralMultiline(t *testing.T) {
 	}
 }
 
-func TestEncoderUseLiteralMultilineBelowThreshold(t *testing.T) {
+func TestEncoderLiteralMultilineBelowThreshold(t *testing.T) {
 	// A multi-line value shorter than the threshold must remain escaped.
 	type Cfg struct {
 		Short string `toml:"short"`
 	}
-	out, err := NewEncoder().UseLiteralMultiline(1000).Marshal(Cfg{Short: "one\ntwo"})
+	out, err := NewEncoder().LiteralMultiline(1000).Marshal(Cfg{Short: "one\ntwo"})
 	if err != nil {
 		t.Fatalf("marshal: %v", err)
 	}
@@ -254,12 +254,12 @@ func TestEncoderUseLiteralMultilineBelowThreshold(t *testing.T) {
 	}
 }
 
-func TestEncoderUseLiteralMultilineThresholdZero(t *testing.T) {
-	// UseLiteralMultiline(0) disables the literal form entirely.
+func TestEncoderLiteralMultilineThresholdZero(t *testing.T) {
+	// LiteralMultiline(0) disables the literal form entirely.
 	type Cfg struct {
 		S string `toml:"s"`
 	}
-	out, err := NewEncoder().UseLiteralMultiline(0).Marshal(Cfg{S: "a\nb\nc\nd"})
+	out, err := NewEncoder().LiteralMultiline(0).Marshal(Cfg{S: "a\nb\nc\nd"})
 	if err != nil {
 		t.Fatalf("marshal: %v", err)
 	}
@@ -282,7 +282,7 @@ func TestEncoderLiteralMultilineFallsBackWhenUnsafe(t *testing.T) {
 		{"lone carriage return", "first\rsecond\nthird"},
 	}
 	for _, c := range cases {
-		out, err := NewEncoder().UseLiteralMultiline(5).Marshal(map[string]any{"s": c.in})
+		out, err := NewEncoder().LiteralMultiline(5).Marshal(map[string]any{"s": c.in})
 		if err != nil {
 			t.Fatalf("%s: marshal: %v", c.name, err)
 		}
@@ -483,9 +483,9 @@ func TestEncoderChainedOptions(t *testing.T) {
 	}
 	long := strings.Repeat("x", 200)
 	out, err := NewEncoder().
-		GroupByKind(false).
+		Layout(LayoutKindDeclaration).
 		OmitEmptyArrays().
-		UseLiteralMultiline(50).
+		LiteralMultiline(50).
 		Marshal(Cfg{S: "short", I: Inner{V: long}})
 	if err != nil {
 		t.Fatalf("marshal: %v", err)

examples/basic/main.go

@@ -130,12 +130,12 @@ func Run(stdout, stderr io.Writer) int {
 	}
 	fmt.Fprintf(stdout, "\n--- marshal (group by kind, default) ---\n%s", out)
 
-	out2, err := interpres.NewEncoder().GroupByKind(false).Marshal(cfg)
+	out2, err := interpres.NewEncoder().Layout(interpres.LayoutKindDeclaration).Marshal(cfg)
 	if err != nil {
 		fmt.Fprintln(stderr, "marshal:", err)
 		return 1
 	}
-	fmt.Fprintf(stdout, "\n--- marshal (GroupByKind=false) ---\n%s", out2)
+	fmt.Fprintf(stdout, "\n--- marshal (LayoutKindDeclaration) ---\n%s", out2)
 
 	// Demonstrate Unmarshaler-style mutation: re-decode the second output to
 	// prove it round-trips back into the same Go value.

examples/basic/main_test.go

@@ -25,7 +25,7 @@ func TestRunPrintsConfigAndMarshal(t *testing.T) {
 		"admin=false",
 		"--- marshal (group by kind, default) ---",
 		`title = "interpres demo"`,
-		"--- marshal (GroupByKind=false) ---",
+		"--- marshal (LayoutKindDeclaration) ---",
 		"[server]",
 		"port = 9090",
 		"[[users]]",

interpres.go

@@ -545,12 +545,25 @@ func MarshalContext(ctx context.Context, v any) ([]byte, error) {
 	return NewEncoder().MarshalContext(ctx, v)
 }
 
+// A LayoutKind names the layout the encoder writes a document's entries in.
+type LayoutKind int
+
+const (
+	// LayoutKindGrouped reorders entries at one level: scalars first, then
+	// sub-tables, then arrays of tables. The default.
+	LayoutKindGrouped LayoutKind = iota
+	// LayoutKindDeclaration preserves the declaration order: struct field
+	// order, or sorted key order for maps.
+	LayoutKindDeclaration
+)
+
 // An Encoder encodes Go values into TOML.
 //
 // All options default to the behaviour that passes the toml-test compliance
 // suite in both directions:
 //
-//	GroupByKind:        true  (scalars first, then tables, then arrays of tables)
+//	Layout:             LayoutKindGrouped (scalars first, then tables, then
+//	                    arrays of tables)
 //	OmitEmptyArrays:    false (a nil/empty []string slice emits [] as a value;
 //	                          a nil/empty []Item struct slice is still skipped)
 //	LiteralMultilineAt: 0     (always emit the escaped basic form, never a
@@ -562,22 +575,21 @@ func MarshalContext(ctx context.Context, v any) ([]byte, error) {
 // callers that need the underlying knobs reach for the methods rather than
 // reading or mutating fields.
 type Encoder struct {
-	groupByKind        bool // default true; set via (*Encoder).GroupByKind
+	layout             LayoutKind // default LayoutKindGrouped; set via (*Encoder).Layout
 	omitEmptyArrays    bool       // default false; set via (*Encoder).OmitEmptyArrays
-	literalMultilineAt int  // default 0; set via (*Encoder).UseLiteralMultiline
+	literalMultilineAt int        // default 0; set via (*Encoder).LiteralMultiline
 	inlineTablesAt     int        // default 0; set via (*Encoder).InlineTables
 	emitFieldComments  bool       // default false; set via (*Encoder).EmitFieldComments
 }
 
 // NewEncoder returns an Encoder with default options.
-func NewEncoder() *Encoder { return &Encoder{groupByKind: true} }
+func NewEncoder() *Encoder { return &Encoder{layout: LayoutKindGrouped} }
 
-// GroupByKind toggles whether fields at the same TOML level are reordered
-// into the group-by-kind layout (scalars first, then tables, then arrays of
-// tables). When set to false, the emitter preserves the source declaration
-// order (struct field order, or sorted key order for maps).
-func (e *Encoder) GroupByKind(v bool) *Encoder {
-	e.groupByKind = v
+// Layout sets the layout the encoder writes a document's entries in:
+// LayoutKindGrouped, the default, reorders them scalars first, then tables,
+// then arrays of tables; LayoutKindDeclaration preserves declaration order.
+func (e *Encoder) Layout(kind LayoutKind) *Encoder {
+	e.layout = kind
 	return e
 }
 
@@ -589,12 +601,12 @@ func (e *Encoder) OmitEmptyArrays() *Encoder {
 	return e
 }
 
-// UseLiteralMultiline sets the length threshold at which a multi-line string
+// LiteralMultiline sets the length threshold at which a multi-line string
 // is emitted as a literal triple-quoted string instead of the escaped form.
 // Use 0 or any negative value to disable (always escaped). The literal form
 // is selected only when the value contains an internal newline; otherwise the
 // single-line basic form is used regardless of this setting.
-func (e *Encoder) UseLiteralMultiline(threshold int) *Encoder {
+func (e *Encoder) LiteralMultiline(threshold int) *Encoder {
 	e.literalMultilineAt = threshold
 	return e
 }
@@ -609,7 +621,7 @@ func (e *Encoder) UseLiteralMultiline(threshold int) *Encoder {
 // value array. An inlined table that does not fit the line is written across
 // lines, which TOML 1.1 allows.
 //
-// With GroupByKind(false) the layout is already for presentation only, and an
+// With LayoutKindDeclaration the layout is already for presentation only, and an
 // inlined table follows the same rule as any other value line: it lands in the
 // section of the header that precedes it.
 func (e *Encoder) InlineTables(threshold int) *Encoder {