fix(document): rebuild set nodes and write documents back round-trip

Assisted-by: GLM 5.3

document.go

@@ -34,15 +34,31 @@ func (d *Document) Root() *Table {
 }
 
 // Map returns the value tree, the shape ParseMap gives. It is the tree the
-// document was parsed into, not a copy.
+// document was parsed into, not a copy. A nil document or one with no root
-func (d *Document) Map() map[string]any { return d.root.values }
+// holds no values.
+func (d *Document) Map() map[string]any {
+	if d == nil || d.root == nil {
+		return nil
+	}
+	return d.root.values
+}
 
 // Footer returns the comment lines that follow the last statement, and every
 // line of a document that holds no statement at all.
-func (d *Document) Footer() []string { return d.footer }
+func (d *Document) Footer() []string {
+	if d == nil {
+		return nil
+	}
+	return d.footer
+}
 
 // SetFooter replaces those lines.
-func (d *Document) SetFooter(lines []string) { d.footer = lines }
+func (d *Document) SetFooter(lines []string) {
+	if d == nil {
+		return
+	}
+	d.footer = lines
+}
 
 // The document-level convenience forms of the Table edit API; they act on
 // the root table.
@@ -87,6 +103,11 @@ type Table struct {
 	// rather than under a header or as a dotted key.
 	inline bool
 
+	// dotted records that a dotted key introduced the table, `a.b = 1`
+	// building the a around the leaf: the write side gives such a table back
+	// as dotted key lines, the form that holds the position of a line.
+	dotted bool
+
 	// comments are the lines above the table's header, trailing is the comment
 	// on the header's own line. Both are empty for a table a dotted key
 	// introduced, which has no line of its own.
@@ -98,8 +119,12 @@ func newTable(values map[string]any) *Table {
 	return &Table{values: values, index: map[string]*Entry{}}
 }
 
-// Keys returns the table's keys in the order they were written.
+// Keys returns the table's keys in the order they were written. A nil table
+// holds none, the answer a document without a root gives through Root.
 func (t *Table) Keys() []string {
+	if t == nil {
+		return nil
+	}
 	keys := make([]string, len(t.entries))
 	for i, e := range t.entries {
 		keys[i] = e.key
@@ -109,43 +134,75 @@ func (t *Table) Keys() []string {
 
 // Values returns the table's values, which is the map the value tree holds for
 // it.
-func (t *Table) Values() map[string]any { return t.values }
+func (t *Table) Values() map[string]any {
+	if t == nil {
+		return nil
+	}
+	return t.values
+}
 
 // Entries returns the table's entries in written order.
-func (t *Table) Entries() []*Entry { return t.entries }
+func (t *Table) Entries() []*Entry {
+	if t == nil {
+		return nil
+	}
+	return t.entries
+}
 
 // Get returns the entry for key, and whether the table has one.
 func (t *Table) Get(key string) (*Entry, bool) {
+	if t == nil {
+		return nil, false
+	}
 	e, ok := t.index[key]
 	return e, ok
 }
 
 // Inline reports whether the table was written as an inline table, `{…}`,
 // rather than under a header or introduced by a dotted key.
-func (t *Table) Inline() bool { return t.inline }
+func (t *Table) Inline() bool { return t != nil && t.inline }
 
 // Comments returns the comment lines above the table's header, or above the
 // key that introduced it. Lines carry no leading '#' and no surrounding space.
-func (t *Table) Comments() []string { return t.comments }
+func (t *Table) Comments() []string {
+	if t == nil {
+		return nil
+	}
+	return t.comments
+}
 
 // SetComments replaces those lines. Each line is written back with a "# " in
 // front of it, so a line should not carry one.
-func (t *Table) SetComments(lines []string) { t.comments = lines }
+func (t *Table) SetComments(lines []string) {
+	if t == nil {
+		return
+	}
+	t.comments = lines
+}
 
 // Trailing returns the comment on the header's own line, without the '#'.
-func (t *Table) Trailing() string { return t.trailing }
+func (t *Table) Trailing() string {
+	if t == nil {
+		return ""
+	}
+	return t.trailing
+}
 
 // SetTrailing replaces that comment.
-func (t *Table) SetTrailing(line string) { t.trailing = line }
+func (t *Table) SetTrailing(line string) {
+	if t == nil {
+		return
+	}
+	t.trailing = line
+}
 
-// addValue records a key of the table, in written order.
+// addValue records a key of the table, in written order. The caller gives
+// the entry a table node or element nodes when the value has that shape; a
+// map value left without a node writes as an inline table.
 func (t *Table) addValue(key string, val any, inline bool) *Entry {
 	e := &Entry{table: t, key: key, inline: inline}
 	t.entries = append(t.entries, e)
 	t.index[key] = e
-	if node, ok := val.(map[string]any); ok {
-		e.child = newTable(node)
-	}
 	return e
 }
 
@@ -178,6 +235,9 @@ func (t *Table) addElement(key string, values map[string]any) *Table {
 
 // child returns the node of a table-valued key, or nil.
 func (t *Table) child(key string) *Table {
+	if t == nil {
+		return nil
+	}
 	if e, ok := t.index[key]; ok {
 		return e.child
 	}
@@ -239,6 +299,9 @@ func (e *Entry) SetTrailing(line string) { e.trailing = line }
 
 // GetString returns the string the key holds, and whether it holds one.
 func (t *Table) GetString(key string) (string, bool) {
+	if t == nil {
+		return "", false
+	}
 	v, ok := t.values[key]
 	s, ok := v.(string)
 	return s, ok
@@ -246,6 +309,9 @@ func (t *Table) GetString(key string) (string, bool) {
 
 // GetInt returns the integer the key holds, and whether it holds one.
 func (t *Table) GetInt(key string) (int64, bool) {
+	if t == nil {
+		return 0, false
+	}
 	v, ok := t.values[key]
 	i, ok := v.(int64)
 	return i, ok
@@ -253,6 +319,9 @@ func (t *Table) GetInt(key string) (int64, bool) {
 
 // GetFloat returns the float the key holds, and whether it holds one.
 func (t *Table) GetFloat(key string) (float64, bool) {
+	if t == nil {
+		return 0, false
+	}
 	v, ok := t.values[key]
 	f, ok := v.(float64)
 	return f, ok
@@ -260,6 +329,9 @@ func (t *Table) GetFloat(key string) (float64, bool) {
 
 // GetBool returns the boolean the key holds, and whether it holds one.
 func (t *Table) GetBool(key string) (bool, bool) {
+	if t == nil {
+		return false, false
+	}
 	v, ok := t.values[key]
 	b, ok := v.(bool)
 	return b, ok
@@ -267,6 +339,9 @@ func (t *Table) GetBool(key string) (bool, bool) {
 
 // GetArray returns the value array the key holds, and whether it holds one.
 func (t *Table) GetArray(key string) ([]any, bool) {
+	if t == nil {
+		return nil, false
+	}
 	v, ok := t.values[key]
 	a, ok := v.([]any)
 	return a, ok
@@ -282,9 +357,13 @@ func (t *Table) GetTable(key string) (*Table, bool) {
 // Set stores value under key. A key the table already has keeps its position
 // and its comments; a new one joins the end. A value of map[string]any
 // becomes a table node of its own, written under a header like any other
-// table; a Go map carries no order, so its keys take sorted order. A value
+// table, and replaces the node the key held, which belonged to the value the
+// key held; a Go map carries no order, so its keys take sorted order. A value
 // of []map[string]any becomes an array-of-tables node.
 func (t *Table) Set(key string, value any) {
+	if t == nil {
+		return
+	}
 	e, ok := t.index[key]
 	if !ok {
 		t.values[key] = value
@@ -303,11 +382,10 @@ func (t *Table) Set(key string, value any) {
 	t.values[key] = value
 	switch v := value.(type) {
 	case map[string]any:
-		if e.child == nil {
+		// The node is rebuilt rather than patched: the entries and the index
-			e.child = newOrderedTable(v)
+		// belong to the table the key held, and writing the new value
-		} else {
+		// through them would leave the old table's keys in the output.
-			e.child.values = v
+		e.child = newOrderedTable(v)
-		}
 		e.elements = nil
 	case []map[string]any:
 		e.child = nil
@@ -322,15 +400,30 @@ func (t *Table) Set(key string, value any) {
 }
 
 // newOrderedTable builds a table node for a value the caller set, its keys
-// entered as entries in sorted order, the order Marshal writes maps in.
+// entered in sorted order, the order Marshal writes maps in.
 func newOrderedTable(m map[string]any) *Table {
+	return orderedTable(m, 0)
+}
+
+// orderedTable is newOrderedTable's recursion. The depth bound is the value
+// encoder's: a cyclic map stopped here is written by the value writer, which
+// reports it instead of running the stack out.
+func orderedTable(m map[string]any, depth int) *Table {
 	t := newTable(m)
 	for _, k := range slices.Sorted(maps.Keys(m)) {
 		v := m[k]
-		_, isMap := v.(map[string]any)
 		e := t.addValue(k, v, false)
-		if isMap {
+		if depth >= maxEncodeDepth {
-			e.child = newOrderedTable(v.(map[string]any))
+			continue
+		}
+		switch val := v.(type) {
+		case map[string]any:
+			e.child = orderedTable(val, depth+1)
+		case []map[string]any:
+			e.elements = make([]*Table, len(val))
+			for i, item := range val {
+				e.elements[i] = orderedTable(item, depth+1)
+			}
 		}
 	}
 	return t
@@ -338,6 +431,9 @@ func newOrderedTable(m map[string]any) *Table {
 
 // Delete removes key and everything it holds.
 func (t *Table) Delete(key string) {
+	if t == nil {
+		return
+	}
 	if _, ok := t.values[key]; !ok {
 		return
 	}

document_test.go

@@ -4,6 +4,7 @@
 package interpres
 
 import (
+	"reflect"
 	"slices"
 	"strings"
 	"testing"
@@ -416,3 +417,143 @@ func TestDocumentEditPipeline(t *testing.T) {
 		}
 	})
 }
+
+// TestMarshalDocumentRoundTrips pins that a parsed document written back
+// re-parses to the same tree: arrays of tables keep exactly one header per
+// element, dotted keys hold their line position without swallowing the keys
+// after them, inline tables inside value arrays keep their written order,
+// and comments travel with their statements.
+func TestMarshalDocumentRoundTrips(t *testing.T) {
+	tests := []struct {
+		name string
+		src  string
+	}{
+		{"array of tables", "[[items]]\nname = \"a\"\n\n[[items]]\nname = \"b\"\n"},
+		{"array of tables with comments", "# about items\n[[items]] # first\nname = \"a\"\n"},
+		{"dotted key before a later key", "a.b = 1\nc = 2\n"},
+		{"dotted keys grouped", "a.b = 1\na.c = 2\nd = 3\n"},
+		{"dotted key with a nested leaf", "a.b.c = 1\nz = 2\n"},
+		{"header section after a dotted key", "a.b = 1\n\n[a.x]\ny = 2\n"},
+		{"inline tables in a value array keep order", "arr = [{y = 1, x = 2}, {second = true, first = false}]\n"},
+		{"nested array of tables", "[[items]]\nn = 1\n\n[items.sub]\nk = \"v\"\n"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			doc, err := Parse([]byte(tt.src))
+			if err != nil {
+				t.Fatalf("Parse: %v", err)
+			}
+			out, err := Marshal(doc)
+			if err != nil {
+				t.Fatalf("Marshal: %v", err)
+			}
+			reparsed, err := Parse(out)
+			if err != nil {
+				t.Fatalf("re-parse of %q: %v", out, err)
+			}
+			if !reflect.DeepEqual(doc.Map(), reparsed.Map()) {
+				t.Errorf("round trip changed the tree:\nin:  %#v\nout: %#v", doc.Map(), reparsed.Map())
+			}
+			if got, want := reparsed.Root().Keys(), doc.Root().Keys(); !slices.Equal(got, want) {
+				t.Errorf("root keys = %v, want %v", got, want)
+			}
+		})
+	}
+}
+
+// TestMarshalDocumentArrayComments pins where the comments of an array of
+// tables land: above and beside the [[header]] itself.
+func TestMarshalDocumentArrayComments(t *testing.T) {
+	doc, err := Parse([]byte("# element one\n[[items]] # trailing\nname = \"a\"\n"))
+	if err != nil {
+		t.Fatalf("Parse: %v", err)
+	}
+	out, err := Marshal(doc)
+	if err != nil {
+		t.Fatalf("Marshal: %v", err)
+	}
+	want := "# element one\n[[items]] # trailing\nname = \"a\"\n"
+	if string(out) != want {
+		t.Errorf("output = %q, want %q", out, want)
+	}
+}
+
+// TestTableSetReplacesTableNode pins that Set over a key holding a table
+// rebuilds the node, so the new map's keys are the ones written.
+func TestTableSetReplacesTableNode(t *testing.T) {
+	doc, err := Parse([]byte("[cache]\nz = 1\n"))
+	if err != nil {
+		t.Fatalf("Parse: %v", err)
+	}
+	doc.Set("cache", map[string]any{"a": int64(2)})
+	out, err := Marshal(doc)
+	if err != nil {
+		t.Fatalf("Marshal: %v", err)
+	}
+	want := "[cache]\na = 2\n"
+	if string(out) != want {
+		t.Errorf("output = %q, want %q", out, want)
+	}
+}
+
+// TestTableSetNestedArraysOfTables pins that a value set through the edit API
+// carries its arrays of tables into the header form.
+func TestTableSetNestedArraysOfTables(t *testing.T) {
+	doc, err := Parse([]byte("x = 1\n"))
+	if err != nil {
+		t.Fatalf("Parse: %v", err)
+	}
+	doc.Set("t", map[string]any{"items": []map[string]any{{"n": int64(1)}, {"n": int64(2)}}})
+	out, err := Marshal(doc)
+	if err != nil {
+		t.Fatalf("Marshal: %v", err)
+	}
+	if !strings.Contains(string(out), "[[t.items]]") {
+		t.Errorf("output = %q, want the array of tables under a header", out)
+	}
+}
+
+// TestTableSetCyclicMapErrors pins that a cyclic map set through the edit API
+// reaches the depth limit instead of the stack.
+func TestTableSetCyclicMapErrors(t *testing.T) {
+	doc, err := Parse([]byte("x = 1\n"))
+	if err != nil {
+		t.Fatalf("Parse: %v", err)
+	}
+	m := map[string]any{}
+	m["self"] = m
+	doc.Set("cyclic", m)
+	if _, err := Marshal(doc); err == nil || !strings.Contains(err.Error(), "nests deeper") {
+		t.Errorf("err = %v, want the depth-limit complaint", err)
+	}
+}
+
+// TestDocumentNilSafety pins that the nil document answers its readers
+// instead of panicking, the contract Root already carries.
+func TestDocumentNilSafety(t *testing.T) {
+	var doc *Document
+	if doc.Map() != nil {
+		t.Errorf("Map = %v", doc.Map())
+	}
+	if doc.Footer() != nil {
+		t.Errorf("Footer = %v", doc.Footer())
+	}
+	doc.SetFooter([]string{"x"})
+	if e, ok := doc.Get("k"); e != nil || ok {
+		t.Errorf("Get = %v, %v", e, ok)
+	}
+	if _, ok := doc.GetString("k"); ok {
+		t.Error("GetString on a nil document reports a value")
+	}
+	if _, ok := doc.GetTable("k"); ok {
+		t.Error("GetTable on a nil document reports a value")
+	}
+	doc.Set("k", 1)
+	doc.Delete("k")
+	if keys := doc.Root().Keys(); keys != nil {
+		t.Errorf("Keys = %v", keys)
+	}
+	if doc.Root().Entries() != nil {
+		t.Errorf("Entries = %v", doc.Root().Entries())
+	}
+}

docwrite.go

@@ -43,8 +43,8 @@ func (e *encoder) writeDocument(doc *Document) error {
 }
 
 // writeDocumentFooter writes the comment lines that follow the last
-// statement, each separated from it by a blank line, the shape the parser
+// statement. The parser collects them wherever they sit after it, so the
-// reads them back from.
+// writer needs no blank line of its own to have them read back.
 func (e *encoder) writeDocumentFooter(footer []string) {
 	for _, line := range footer {
 		e.buf.WriteString("# ")
@@ -53,8 +53,9 @@ func (e *encoder) writeDocumentFooter(footer []string) {
 	}
 }
 
-// writeTableEntries writes one table's entries in written order at the given
+// writeTableEntries writes one table at the given header path, nil for the
-// header path, nil for the document root, whose keys need no header.
+// document root, whose keys need no header: the blank line, the comments,
+// the header line with its trailing comment, then the body.
 func (e *encoder) writeTableEntries(t *Table, path []string) error {
 	if t == nil {
 		return nil
@@ -66,77 +67,222 @@ func (e *encoder) writeTableEntries(t *Table, path []string) error {
 		if err := e.writeKeyPath(path); err != nil {
 			return err
 		}
-		e.buf.WriteString("]\n")
+		e.buf.WriteString("]")
 		if tr := t.Trailing(); tr != "" {
 			e.buf.WriteString(" # ")
 			e.buf.WriteString(tr)
-			e.buf.WriteByte('\n')
+		}
+		e.buf.WriteByte('\n')
+	}
+	return e.writeTableBody(t, path)
+}
+
+// writeTableBody writes one table's entries: the value lines first, in
+// written order, then the header sections. In a valid document every line at
+// one level precedes the headers below it, so the split reorders nothing;
+// what it prevents is a table a dotted key introduced, which the parse nests
+// as a sub-table at the position of a line, from swallowing the lines that
+// follow it into its header.
+func (e *encoder) writeTableBody(t *Table, path []string) error {
+	for _, entry := range t.Entries() {
+		if err := e.checkCtx(); err != nil {
+			return err
+		}
+		if !e.isLineEntry(entry) {
+			continue
+		}
+		if err := e.writeLineEntry(entry, path); err != nil {
+			return err
 		}
 	}
 	for _, entry := range t.Entries() {
 		if err := e.checkCtx(); err != nil {
 			return err
 		}
-		if _, isTables := entry.Value().([]map[string]any); isTables && len(entry.Elements()) > 0 {
+		if child := entry.Table(); child != nil && child.dotted && !entry.Inline() {
-			for i, el := range entry.Elements() {
+			// A dotted table writes as lines above; its own header-form
-				elemPath := append(append([]string{}, path...), entry.Key())
+			// sub-tables are sections the document placed after those lines,
-				e.writeBlankLine()
+			// so the section pass reaches through the dotted entry.
-				if i == 0 {
+			if err := e.writeDottedSections(child, append(append([]string{}, path...), entry.Key())); err != nil {
-					e.writeComments(entry.Comments())
-				}
-				e.buf.WriteString("[[")
-				if err := e.writeKeyPath(elemPath); err != nil {
-					return err
-				}
-				e.buf.WriteString("]]\n")
-				if err := e.writeTableEntries(el, elemPath); err != nil {
-					return err
-				}
-			}
-			continue
-		}
-		if child := entry.Table(); child != nil && !entry.Inline() {
-			headerPath := append(append([]string{}, path...), entry.Key())
-			if err := e.writeTableEntries(child, headerPath); err != nil {
 				return err
 			}
 			continue
 		}
-		if err := e.writeDocumentEntry(entry, path); err != nil {
+		if e.isLineEntry(entry) {
+			continue
+		}
+		if err := e.writeSectionEntry(entry, path); err != nil {
 			return err
 		}
 	}
 	return nil
 }
 
+// writeDottedSections writes the header-form sub-tables of a dotted table:
+// the sections the document placed after the dotted lines, reached through
+// the dotted entry itself.
+func (e *encoder) writeDottedSections(t *Table, path []string) error {
+	for _, entry := range t.Entries() {
+		if err := e.checkCtx(); err != nil {
+			return err
+		}
+		if child := entry.Table(); child != nil && child.dotted && !entry.Inline() {
+			if err := e.writeDottedSections(child, append(append([]string{}, path...), entry.Key())); err != nil {
+				return err
+			}
+			continue
+		}
+		if e.isLineEntry(entry) {
+			continue
+		}
+		if err := e.writeSectionEntry(entry, path); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// writeSectionEntry writes one entry the line pass left behind: a table or
+// an array of tables under its header, at the path this level carries.
+func (e *encoder) writeSectionEntry(entry *Entry, path []string) error {
+	if _, isTables := entry.Value().([]map[string]any); isTables {
+		// An array of tables keeps its header form, one element per header
+		// with the element's own comments above it; the body that follows is
+		// the element's, with no header of its own to repeat.
+		elemPath := append(append([]string{}, path...), entry.Key())
+		for i, el := range entry.Elements() {
+			e.writeBlankLine()
+			if i == 0 {
+				e.writeComments(entry.Comments())
+			}
+			e.writeComments(el.Comments())
+			e.buf.WriteString("[[")
+			if err := e.writeKeyPath(elemPath); err != nil {
+				return err
+			}
+			e.buf.WriteString("]]")
+			if tr := el.Trailing(); tr != "" {
+				e.buf.WriteString(" # ")
+				e.buf.WriteString(tr)
+			}
+			e.buf.WriteByte('\n')
+			if err := e.writeTableBody(el, elemPath); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+	headerPath := append(append([]string{}, path...), entry.Key())
+	return e.writeTableEntries(entry.Table(), headerPath)
+}
+
+// isLineEntry reports whether an entry writes as one or more "key = value"
+// lines at its own level: a value, an inline table, or a table a dotted key
+// introduced, which goes back as dotted keys. An emptied array of tables
+// counts as one only so the line pass can drop it, the omission the value
+// encoder applies to an empty array of tables too.
+func (e *encoder) isLineEntry(entry *Entry) bool {
+	if child := entry.Table(); child != nil {
+		return entry.Inline() || child.dotted
+	}
+	if _, isTables := entry.Value().([]map[string]any); isTables {
+		return len(entry.Elements()) == 0
+	}
+	return true
+}
+
+// writeLineEntry writes one entry as lines at this level, and drops an
+// emptied array of tables, which has no TOML form.
+func (e *encoder) writeLineEntry(entry *Entry, path []string) error {
+	if child := entry.Table(); child != nil && !entry.Inline() {
+		return e.writeDottedTable(child, append(append([]string{}, path...), entry.Key()))
+	}
+	if _, isTables := entry.Value().([]map[string]any); isTables {
+		return nil
+	}
+	return e.writeDocumentEntry(entry)
+}
+
+// writeDottedTable writes a table a dotted key introduced as one dotted line
+// per leaf, in written order: `a.b = 1`. A sub-table the document added
+// under a header stays a section and is left to the section pass.
+func (e *encoder) writeDottedTable(t *Table, path []string) error {
+	for _, entry := range t.Entries() {
+		if err := e.checkCtx(); err != nil {
+			return err
+		}
+		if child := entry.Table(); child != nil && !entry.Inline() && !child.dotted {
+			continue
+		}
+		leafPath := append(append([]string{}, path...), entry.Key())
+		if child := entry.Table(); child != nil && !entry.Inline() {
+			if err := e.writeDottedTable(child, leafPath); err != nil {
+				return err
+			}
+			continue
+		}
+		e.writeComments(entry.Comments())
+		if err := e.writeKeyPath(leafPath); err != nil {
+			return err
+		}
+		e.buf.WriteString(" = ")
+		if err := e.writeEntryValueNodes(entry); err != nil {
+			return err
+		}
+		e.buf.WriteByte('\n')
+	}
+	return nil
+}
+
 // writeDocumentEntry writes one "key = value" line of a document, with the
 // comments the key carried. A value that is itself an inline table renders
 // inline from its node, in the written order.
-func (e *encoder) writeDocumentEntry(entry *Entry, path []string) error {
+func (e *encoder) writeDocumentEntry(entry *Entry) error {
 	e.writeComments(entry.Comments())
 	if err := e.writeKey(entry.Key()); err != nil {
 		return err
 	}
 	e.buf.WriteString(" = ")
+	if err := e.writeEntryValueNodes(entry); err != nil {
+		return err
+	}
+	e.buf.WriteByte('\n')
+	return nil
+}
+
+// writeEntryValueNodes writes the value of a document entry. An inline table
+// node keeps the written key order even inside a value array, where the
+// ordinary value writer would sort the keys.
+func (e *encoder) writeEntryValueNodes(entry *Entry) error {
 	if child := entry.Table(); child != nil {
 		if err := e.writeInlineTableNode(child); err != nil {
 			return err
 		}
-		if tr := entry.Trailing(); tr != "" {
+	} else if arr, ok := entry.Value().([]any); ok {
-			e.buf.WriteString(" # ")
+		elems := entry.Elements()
-			e.buf.WriteString(tr)
+		e.buf.WriteByte('[')
+		for i, item := range arr {
+			if i > 0 {
+				e.buf.WriteString(", ")
+			}
+			if i < len(elems) && elems[i] != nil {
+				if err := e.writeInlineTableNode(elems[i]); err != nil {
+					return err
+				}
+				continue
+			}
+			if err := e.writeValue(item); err != nil {
+				return err
+			}
 		}
-		e.buf.WriteByte('\n')
+		e.buf.WriteByte(']')
-		return nil
+	} else if err := e.writeValue(entry.Value()); err != nil {
-	}
-	if err := e.writeValue(entry.Value()); err != nil {
 		return err
 	}
 	if tr := entry.Trailing(); tr != "" {
 		e.buf.WriteString(" # ")
 		e.buf.WriteString(tr)
 	}
-	e.buf.WriteByte('\n')
 	return nil
 }