pkg/parse: Turn most public methods of Node into functions.

This make the godoc of the parse package much cleaner and removes some
boilerplate.

pkg/edit/complete/completers.go

@@ -8,6 +8,8 @@ import (
 	"github.com/elves/elvish/pkg/parse"
 )
 
+var parent = parse.Parent
+
 var completers = []completer{
 	completeCommand,
 	completeIndex,
@@ -28,7 +30,7 @@ type context struct {
 func completeArg(n parse.Node, cfg Config) (*context, []RawItem, error) {
 	ev := cfg.PureEvaler
 	if sep, ok := n.(*parse.Sep); ok {
-		if form, ok := sep.Parent().(*parse.Form); ok && form.Head != nil {
+		if form, ok := parent(sep).(*parse.Form); ok && form.Head != nil {
 			// Case 1: starting a new argument.
 			ctx := &context{"argument", "", parse.Bareword, range0(n.Range().To)}
 			args := purelyEvalForm(form, "", n.Range().To, ev)
@@ -38,7 +40,7 @@ func completeArg(n parse.Node, cfg Config) (*context, []RawItem, error) {
 	}
 	if primary, ok := n.(*parse.Primary); ok {
 		if compound, seed := primaryInSimpleCompound(primary, ev); compound != nil {
-			if form, ok := compound.Parent().(*parse.Form); ok {
+			if form, ok := parent(compound).(*parse.Form); ok {
 				if form.Head != nil && form.Head != compound {
 					// Case 2: in an incomplete argument.
 					ctx := &context{"argument", seed, primary.Type, compound.Range()}
@@ -67,7 +69,7 @@ func completeCommand(n parse.Node, cfg Config) (*context, []RawItem, error) {
 		return generateForEmpty(n.Range().To)
 	}
 	if is(n, aSep) {
-		parent := n.Parent()
+		parent := parent(n)
 		switch {
 		case is(parent, aChunk), is(parent, aPipeline):
 			// Case 2: Just after a newline, semicolon, or a pipe.
@@ -83,7 +85,7 @@ func completeCommand(n parse.Node, cfg Config) (*context, []RawItem, error) {
 
 	if primary, ok := n.(*parse.Primary); ok {
 		if compound, seed := primaryInSimpleCompound(primary, ev); compound != nil {
-			if form, ok := compound.Parent().(*parse.Form); ok {
+			if form, ok := parent(compound).(*parse.Form); ok {
 				if form.Head == compound {
 					// Case 4: At an already started command.
 					ctx := &context{
@@ -107,20 +109,20 @@ func completeIndex(n parse.Node, cfg Config) (*context, []RawItem, error) {
 	}
 
 	if is(n, aSep) {
-		if is(n.Parent(), aIndexing) {
+		if is(parent(n), aIndexing) {
 			// We are just after an opening bracket.
-			indexing := n.Parent().(*parse.Indexing)
+			indexing := parent(n).(*parse.Indexing)
 			if len(indexing.Indicies) == 1 {
 				if indexee := ev.PurelyEvalPrimary(indexing.Head); indexee != nil {
 					return generateForEmpty(indexee, n.Range().To)
 				}
 			}
 		}
-		if is(n.Parent(), aArray) {
-			array := n.Parent()
-			if is(array.Parent(), aIndexing) {
+		if is(parent(n), aArray) {
+			array := parent(n)
+			if is(parent(array), aIndexing) {
 				// We are after an existing index and spaces.
-				indexing := array.Parent().(*parse.Indexing)
+				indexing := parent(array).(*parse.Indexing)
 				if len(indexing.Indicies) == 1 {
 					if indexee := ev.PurelyEvalPrimary(indexing.Head); indexee != nil {
 						return generateForEmpty(indexee, n.Range().To)
@@ -134,11 +136,11 @@ func completeIndex(n parse.Node, cfg Config) (*context, []RawItem, error) {
 		primary := n.(*parse.Primary)
 		compound, seed := primaryInSimpleCompound(primary, ev)
 		if compound != nil {
-			if is(compound.Parent(), aArray) {
-				array := compound.Parent()
-				if is(array.Parent(), aIndexing) {
+			if is(parent(compound), aArray) {
+				array := parent(compound)
+				if is(parent(array), aIndexing) {
 					// We are just after an incomplete index.
-					indexing := array.Parent().(*parse.Indexing)
+					indexing := parent(array).(*parse.Indexing)
 					if len(indexing.Indicies) == 1 {
 						if indexee := ev.PurelyEvalPrimary(indexing.Head); indexee != nil {
 							ctx := &context{
@@ -156,7 +158,7 @@ func completeIndex(n parse.Node, cfg Config) (*context, []RawItem, error) {
 func completeRedir(n parse.Node, cfg Config) (*context, []RawItem, error) {
 	ev := cfg.PureEvaler
 	if is(n, aSep) {
-		if is(n.Parent(), aRedir) {
+		if is(parent(n), aRedir) {
 			// Empty redirection target.
 			ctx := &context{"redir", "", parse.Bareword, range0(n.Range().To)}
 			items, err := generateFileNames("", false)
@@ -165,7 +167,7 @@ func completeRedir(n parse.Node, cfg Config) (*context, []RawItem, error) {
 	}
 	if primary, ok := n.(*parse.Primary); ok {
 		if compound, seed := primaryInSimpleCompound(primary, ev); compound != nil {
-			if is(compound.Parent(), &parse.Redir{}) {
+			if is(parent(compound), &parse.Redir{}) {
 				// Non-empty redirection target.
 				ctx := &context{
 					"redir", seed, primary.Type, compound.Range()}

pkg/edit/complete/node_utils.go

@@ -25,11 +25,11 @@ var (
 )
 
 func primaryInSimpleCompound(pn *parse.Primary, ev PureEvaler) (*parse.Compound, string) {
-	indexing, ok := pn.Parent().(*parse.Indexing)
+	indexing, ok := parent(pn).(*parse.Indexing)
 	if !ok {
 		return nil, ""
 	}
-	compound, ok := indexing.Parent().(*parse.Compound)
+	compound, ok := parent(indexing).(*parse.Compound)
 	if !ok {
 		return nil, ""
 	}

pkg/edit/highlight.go

@@ -19,7 +19,7 @@ func initHighlighter(appSpec *cli.AppSpec, ev *eval.Evaler) {
 }
 
 func check(ev *eval.Evaler, n *parse.Chunk) error {
-	src := &parse.Source{Name: "[tty]", Code: n.SourceText()}
+	src := &parse.Source{Name: "[tty]", Code: parse.SourceText(n)}
 	_, err := ev.Compile(n, src)
 	return err
 }

pkg/edit/highlight/regions.go

@@ -7,6 +7,8 @@ import (
 	"github.com/elves/elvish/pkg/parse"
 )
 
+var sourceText = parse.SourceText
+
 // Represents a region to be highlighted.
 type region struct {
 	begin int
@@ -106,7 +108,7 @@ func emitRegions(n parse.Node, f func(parse.Node, regionKind, string)) {
 	case *parse.Sep:
 		emitRegionsInSep(n, f)
 	}
-	for _, child := range n.Children() {
+	for _, child := range parse.Children(n) {
 		emitRegions(child, f)
 	}
 }
@@ -137,7 +139,7 @@ func emitRegionsInForm(n *parse.Form, f func(parse.Node, regionKind, string)) {
 	// TODO: This only highlights bareword special commands, however currently
 	// quoted special commands are also possible (e.g `"if" $true { }` is
 	// accepted).
-	switch n.Head.SourceText() {
+	switch sourceText(n.Head) {
 	case "if":
 		emitRegionsInIf(n, f)
 	case "for":
@@ -155,7 +157,7 @@ func emitRegionsInIf(n *parse.Form, f func(parse.Node, regionKind, string)) {
 	// Highlight all "elif" and "else".
 	for i := 2; i < len(n.Args); i += 2 {
 		arg := n.Args[i]
-		if arg.SourceText() == "elif" || arg.SourceText() == "else" {
+		if s := sourceText(arg); s == "elif" || s == "else" {
 			f(arg, semanticRegion, keywordRegion)
 		}
 	}
@@ -167,7 +169,7 @@ func emitRegionsInFor(n *parse.Form, f func(parse.Node, regionKind, string)) {
 		f(n.Args[0].Indexings[0].Head, semanticRegion, variableRegion)
 	}
 	// Highlight "else".
-	if 3 < len(n.Args) && n.Args[3].SourceText() == "else" {
+	if 3 < len(n.Args) && sourceText(n.Args[3]) == "else" {
 		f(n.Args[3], semanticRegion, keywordRegion)
 	}
 }
@@ -177,7 +179,7 @@ func emitRegionsInTry(n *parse.Form, f func(parse.Node, regionKind, string)) {
 	// "finally".
 	i := 1
 	matchKW := func(text string) bool {
-		if i < len(n.Args) && n.Args[i].SourceText() == text {
+		if i < len(n.Args) && sourceText(n.Args[i]) == text {
 			f(n.Args[i], semanticRegion, keywordRegion)
 			return true
 		}
@@ -213,7 +215,7 @@ func emitRegionsInPrimary(n *parse.Primary, f func(parse.Node, regionKind, strin
 }
 
 func emitRegionsInSep(n *parse.Sep, f func(parse.Node, regionKind, string)) {
-	text := n.SourceText()
+	text := sourceText(n)
 	switch {
 	case strings.TrimSpace(text) == "":
 		// Don't do anything; whitespaces do not get highlighted.

pkg/eval/args_walker.go

@@ -40,7 +40,7 @@ func (aw *argsWalker) next() *parse.Compound {
 // nextIs returns whether the next argument's source matches the given text. It
 // also consumes the argument if it is.
 func (aw *argsWalker) nextIs(text string) bool {
-	if aw.more() && aw.form.Args[aw.idx].SourceText() == text {
+	if aw.more() && parse.SourceText(aw.form.Args[aw.idx]) == text {
 		aw.idx++
 		return true
 	}

pkg/eval/builtin_special.go

@@ -564,7 +564,7 @@ func compileTry(cp *compiler, fn *parse.Form) effectOpBody {
 	logger.Println("compiling try")
 	args := cp.walkArgs(fn)
 	bodyNode := args.nextMustLambda()
-	logger.Printf("body is %q", bodyNode.SourceText())
+	logger.Printf("body is %q", parse.SourceText(bodyNode))
 	var exceptVarNode *parse.Indexing
 	var exceptNode *parse.Primary
 	if args.nextIs("except") {

pkg/eval/compile_effect.go

@@ -50,7 +50,7 @@ func (cp *compiler) pipelineOp(n *parse.Pipeline) effectOp {
 	cp.newLocals = saveNewLocals
 
 	return makeEffectOp(n,
-		&pipelineOp{n.Background, n.SourceText(), formOps, newLocals})
+		&pipelineOp{n.Background, parse.SourceText(n), formOps, newLocals})
 }
 
 func (cp *compiler) pipelineOps(ns []*parse.Pipeline) []effectOp {

pkg/eval/compile_value.go

@@ -255,7 +255,7 @@ func (cp *compiler) primaryOp(n *parse.Primary) valuesOp {
 		}
 		body = &variableOp{sigil != "", qname}
 	case parse.Wildcard:
-		seg, err := wildcardToSegment(n.SourceText())
+		seg, err := wildcardToSegment(parse.SourceText(n))
 		if err != nil {
 			cp.errorpf(n, "%s", err)
 		}
@@ -279,7 +279,7 @@ func (cp *compiler) primaryOp(n *parse.Primary) valuesOp {
 		body = cp.braced(n)
 	default:
 		cp.errorpf(n, "bad PrimaryType; parser bug")
-		body = literalStr(n.SourceText())
+		body = literalStr(parse.SourceText(n))
 	}
 	return makeValuesOp(n, body)
 }

pkg/parse/check_ast_test.go

@@ -59,7 +59,7 @@ func checkAST(n Node, want ast) error {
 		if i == len(wantnames)-1 {
 			break
 		}
-		fields := n.Children()
+		fields := Children(n)
 		if len(fields) != 1 {
 			return fmt.Errorf("want exactly 1 child, got %d (%s)", len(fields), summary(n))
 		}
@@ -134,7 +134,7 @@ func checkField(got interface{}, want interface{}, ctx string) error {
 func checkNodeInField(got Node, want interface{}) error {
 	switch want := want.(type) {
 	case string:
-		text := got.SourceText()
+		text := SourceText(got)
 		if want != text {
 			return fmt.Errorf("want %q, got %q (%s)", want, text, summary(got))
 		}

pkg/parse/check_parse_tree_test.go

@@ -4,14 +4,14 @@ import "fmt"
 
 // checkParseTree checks whether the parse tree part of a Node is well-formed.
 func checkParseTree(n Node) error {
-	children := n.Children()
+	children := Children(n)
 	if len(children) == 0 {
 		return nil
 	}
 
 	// Parent pointers of all children should point to me.
 	for i, ch := range children {
-		if ch.Parent() != n {
+		if Parent(ch) != n {
 			return fmt.Errorf("parent of child %d (%s) is wrong: %s", i, summary(ch), summary(n))
 		}
 	}
@@ -33,7 +33,7 @@ func checkParseTree(n Node) error {
 	}
 
 	// Check children recursively.
-	for _, ch := range n.Children() {
+	for _, ch := range Children(n) {
 		err := checkParseTree(ch)
 		if err != nil {
 			return err

pkg/parse/node.go

@@ -4,18 +4,9 @@ import "github.com/elves/elvish/pkg/diag"
 
 // Node represents a parse tree as well as an AST.
 type Node interface {
-	parse(*parser)
-
 	diag.Ranger
-	SourceText() string
-	Parent() Node
-	Children() []Node
-
-	setFrom(int)
-	setTo(int)
-	setSourceText(string)
-	setParent(Node)
-	addChild(Node)
+	parse(*parser)
+	n() *node
 }
 
 type node struct {
@@ -25,34 +16,19 @@ type node struct {
 	children   []Node
 }
 
-func (n *node) setFrom(begin int) { n.From = begin }
-
-func (n *node) setTo(end int) { n.To = end }
-
-func (n *node) setSourceText(source string) { n.sourceText = source }
-
-func (n *node) setParent(p Node) { n.parent = p }
+func (n *node) n() *node { return n }
 
 func (n *node) addChild(ch Node) { n.children = append(n.children, ch) }
 
-// Parent returns the parent node. If the node is the root of the syntax tree,
-// the parent is nil.
-func (n *node) Parent() Node {
-	return n.parent
-}
+// Range returns the range within the full source text that parses to the node.
+func (n *node) Range() diag.Ranging { return n.Ranging }
 
-// Range returns the range within the original (full) source text that parses
-// to the node.
-func (n *node) Range() diag.Ranging {
-	return diag.Ranging{n.From, n.To}
-}
+// Parent returns the parent of a node. It returns nil if the node is the root
+// of the parse tree.
+func Parent(n Node) Node { return n.n().parent }
 
 // SourceText returns the part of the source text that parses to the node.
-func (n *node) SourceText() string {
-	return n.sourceText
-}
+func SourceText(n Node) string { return n.n().sourceText }
 
 // Children returns all children of the node in the parse tree.
-func (n *node) Children() []Node {
-	return n.children
-}
+func Children(n Node) []Node { return n.n().children }

pkg/parse/parse.go

@@ -905,7 +905,7 @@ func (*Sep) parse(*parser) {
 
 func addSep(n Node, ps *parser) {
 	var begin int
-	ch := n.Children()
+	ch := Children(n)
 	if len(ch) > 0 {
 		begin = ch[len(ch)-1].Range().To
 	} else {
@@ -971,6 +971,6 @@ func IsWhitespace(r rune) bool {
 }
 
 func addChild(p Node, ch Node) {
-	p.addChild(ch)
-	ch.setParent(p)
+	p.n().addChild(ch)
+	ch.n().parent = p
 }

pkg/parse/parser.go

@@ -29,10 +29,10 @@ func newParser(srcname, src string) *parser {
 
 func (ps *parser) parse(n Node) parsed {
 	begin := ps.pos
-	n.setFrom(begin)
+	n.n().From = begin
 	n.parse(ps)
-	n.setTo(ps.pos)
-	n.setSourceText(ps.src[begin:ps.pos])
+	n.n().To = ps.pos
+	n.n().sourceText = ps.src[begin:ps.pos]
 	return parsed{n}
 }
 

pkg/parse/parseutil/parseutil.go

@@ -11,8 +11,8 @@ import (
 // position is out of bound.
 func FindLeafNode(n parse.Node, p int) parse.Node {
 descend:
-	for len(n.Children()) > 0 {
-		for _, ch := range n.Children() {
+	for len(parse.Children(n)) > 0 {
+		for _, ch := range parse.Children(n) {
 			if ch.Range().From <= p && p <= ch.Range().To {
 				n = ch
 				continue descend
@@ -30,14 +30,14 @@ func Wordify(src string) []string {
 }
 
 func wordifyInner(n parse.Node, words []string) []string {
-	if len(n.Children()) == 0 || isCompound(n) {
-		text := n.SourceText()
+	if len(parse.Children(n)) == 0 || isCompound(n) {
+		text := parse.SourceText(n)
 		if strings.TrimFunc(text, parse.IsWhitespace) != "" {
 			return append(words, text)
 		}
 		return words
 	}
-	for _, ch := range n.Children() {
+	for _, ch := range parse.Children(n) {
 		words = wordifyInner(ch, words)
 	}
 	return words

pkg/parse/pprint.go

@@ -63,9 +63,9 @@ func pprintASTRec(n Node, wr io.Writer, indent int, leading string) {
 	}
 
 	// has only one child and nothing more : coalesce
-	if len(n.Children()) == 1 &&
-		n.Children()[0].SourceText() == n.SourceText() {
-		pprintASTRec(n.Children()[0], wr, indent, leading+nt.Name()+"/")
+	if len(Children(n)) == 1 &&
+		SourceText(Children(n)[0]) == SourceText(n) {
+		pprintASTRec(Children(n)[0], wr, indent, leading+nt.Name()+"/")
 		return
 	}
 	// print heading
@@ -113,19 +113,19 @@ func pprintParseTree(n Node, w io.Writer) {
 
 func pprintParseTreeRec(n Node, wr io.Writer, indent int) {
 	leading := ""
-	for len(n.Children()) == 1 {
+	for len(Children(n)) == 1 {
 		leading += reflect.TypeOf(n).Elem().Name() + "/"
-		n = n.Children()[0]
+		n = Children(n)[0]
 	}
 	fmt.Fprintf(wr, "%*s%s%s\n", indent, "", leading, summary(n))
-	for _, ch := range n.Children() {
+	for _, ch := range Children(n) {
 		pprintParseTreeRec(ch, wr, indent+indentInc)
 	}
 }
 
 func summary(n Node) string {
 	return fmt.Sprintf("%s %s %d-%d", reflect.TypeOf(n).Elem().Name(),
-		compactQuote(n.SourceText()), n.Range().From, n.Range().To)
+		compactQuote(SourceText(n)), n.Range().From, n.Range().To)
 }
 
 func compactQuote(text string) string {