Adding upstream version 1.16.10.upstream/1.16.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 938 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/syntax/printer.go b/src/cmd/compile/internal/syntax/printer.go
new file mode 100644
index 0000000..8ff3bfa
--- /dev/null
+++ b/src/cmd/compile/internal/syntax/printer.go
@@ -0,0 +1,938 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file implements printing of syntax trees in source format.
+
+package syntax
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"strings"
+)
+
+// TODO(gri) Consider removing the linebreaks flag from this signature.
+// Its likely rarely used in common cases.
+
+func Fprint(w io.Writer, x Node, linebreaks bool) (n int, err error) {
+	p := printer{
+		output:     w,
+		linebreaks: linebreaks,
+	}
+
+	defer func() {
+		n = p.written
+		if e := recover(); e != nil {
+			err = e.(localError).err // re-panics if it's not a localError
+		}
+	}()
+
+	p.print(x)
+	p.flush(_EOF)
+
+	return
+}
+
+func String(n Node) string {
+	var buf bytes.Buffer
+	_, err := Fprint(&buf, n, false)
+	if err != nil {
+		panic(err) // TODO(gri) print something sensible into buf instead
+	}
+	return buf.String()
+}
+
+type ctrlSymbol int
+
+const (
+	none ctrlSymbol = iota
+	semi
+	blank
+	newline
+	indent
+	outdent
+	// comment
+	// eolComment
+)
+
+type whitespace struct {
+	last token
+	kind ctrlSymbol
+	//text string // comment text (possibly ""); valid if kind == comment
+}
+
+type printer struct {
+	output     io.Writer
+	written    int  // number of bytes written
+	linebreaks bool // print linebreaks instead of semis
+
+	indent  int // current indentation level
+	nlcount int // number of consecutive newlines
+
+	pending []whitespace // pending whitespace
+	lastTok token        // last token (after any pending semi) processed by print
+}
+
+// write is a thin wrapper around p.output.Write
+// that takes care of accounting and error handling.
+func (p *printer) write(data []byte) {
+	n, err := p.output.Write(data)
+	p.written += n
+	if err != nil {
+		panic(localError{err})
+	}
+}
+
+var (
+	tabBytes    = []byte("\t\t\t\t\t\t\t\t")
+	newlineByte = []byte("\n")
+	blankByte   = []byte(" ")
+)
+
+func (p *printer) writeBytes(data []byte) {
+	if len(data) == 0 {
+		panic("expected non-empty []byte")
+	}
+	if p.nlcount > 0 && p.indent > 0 {
+		// write indentation
+		n := p.indent
+		for n > len(tabBytes) {
+			p.write(tabBytes)
+			n -= len(tabBytes)
+		}
+		p.write(tabBytes[:n])
+	}
+	p.write(data)
+	p.nlcount = 0
+}
+
+func (p *printer) writeString(s string) {
+	p.writeBytes([]byte(s))
+}
+
+// If impliesSemi returns true for a non-blank line's final token tok,
+// a semicolon is automatically inserted. Vice versa, a semicolon may
+// be omitted in those cases.
+func impliesSemi(tok token) bool {
+	switch tok {
+	case _Name,
+		_Break, _Continue, _Fallthrough, _Return,
+		/*_Inc, _Dec,*/ _Rparen, _Rbrack, _Rbrace: // TODO(gri) fix this
+		return true
+	}
+	return false
+}
+
+// TODO(gri) provide table of []byte values for all tokens to avoid repeated string conversion
+
+func lineComment(text string) bool {
+	return strings.HasPrefix(text, "//")
+}
+
+func (p *printer) addWhitespace(kind ctrlSymbol, text string) {
+	p.pending = append(p.pending, whitespace{p.lastTok, kind /*text*/})
+	switch kind {
+	case semi:
+		p.lastTok = _Semi
+	case newline:
+		p.lastTok = 0
+		// TODO(gri) do we need to handle /*-style comments containing newlines here?
+	}
+}
+
+func (p *printer) flush(next token) {
+	// eliminate semis and redundant whitespace
+	sawNewline := next == _EOF
+	sawParen := next == _Rparen || next == _Rbrace
+	for i := len(p.pending) - 1; i >= 0; i-- {
+		switch p.pending[i].kind {
+		case semi:
+			k := semi
+			if sawParen {
+				sawParen = false
+				k = none // eliminate semi
+			} else if sawNewline && impliesSemi(p.pending[i].last) {
+				sawNewline = false
+				k = none // eliminate semi
+			}
+			p.pending[i].kind = k
+		case newline:
+			sawNewline = true
+		case blank, indent, outdent:
+			// nothing to do
+		// case comment:
+		// 	// A multi-line comment acts like a newline; and a ""
+		// 	// comment implies by definition at least one newline.
+		// 	if text := p.pending[i].text; strings.HasPrefix(text, "/*") && strings.ContainsRune(text, '\n') {
+		// 		sawNewline = true
+		// 	}
+		// case eolComment:
+		// 	// TODO(gri) act depending on sawNewline
+		default:
+			panic("unreachable")
+		}
+	}
+
+	// print pending
+	prev := none
+	for i := range p.pending {
+		switch p.pending[i].kind {
+		case none:
+			// nothing to do
+		case semi:
+			p.writeString(";")
+			p.nlcount = 0
+			prev = semi
+		case blank:
+			if prev != blank {
+				// at most one blank
+				p.writeBytes(blankByte)
+				p.nlcount = 0
+				prev = blank
+			}
+		case newline:
+			const maxEmptyLines = 1
+			if p.nlcount <= maxEmptyLines {
+				p.write(newlineByte)
+				p.nlcount++
+				prev = newline
+			}
+		case indent:
+			p.indent++
+		case outdent:
+			p.indent--
+			if p.indent < 0 {
+				panic("negative indentation")
+			}
+		// case comment:
+		// 	if text := p.pending[i].text; text != "" {
+		// 		p.writeString(text)
+		// 		p.nlcount = 0
+		// 		prev = comment
+		// 	}
+		// 	// TODO(gri) should check that line comments are always followed by newline
+		default:
+			panic("unreachable")
+		}
+	}
+
+	p.pending = p.pending[:0] // re-use underlying array
+}
+
+func mayCombine(prev token, next byte) (b bool) {
+	return // for now
+	// switch prev {
+	// case lexical.Int:
+	// 	b = next == '.' // 1.
+	// case lexical.Add:
+	// 	b = next == '+' // ++
+	// case lexical.Sub:
+	// 	b = next == '-' // --
+	// case lexical.Quo:
+	// 	b = next == '*' // /*
+	// case lexical.Lss:
+	// 	b = next == '-' || next == '<' // <- or <<
+	// case lexical.And:
+	// 	b = next == '&' || next == '^' // && or &^
+	// }
+	// return
+}
+
+func (p *printer) print(args ...interface{}) {
+	for i := 0; i < len(args); i++ {
+		switch x := args[i].(type) {
+		case nil:
+			// we should not reach here but don't crash
+
+		case Node:
+			p.printNode(x)
+
+		case token:
+			// _Name implies an immediately following string
+			// argument which is the actual value to print.
+			var s string
+			if x == _Name {
+				i++
+				if i >= len(args) {
+					panic("missing string argument after _Name")
+				}
+				s = args[i].(string)
+			} else {
+				s = x.String()
+			}
+
+			// TODO(gri) This check seems at the wrong place since it doesn't
+			//           take into account pending white space.
+			if mayCombine(p.lastTok, s[0]) {
+				panic("adjacent tokens combine without whitespace")
+			}
+
+			if x == _Semi {
+				// delay printing of semi
+				p.addWhitespace(semi, "")
+			} else {
+				p.flush(x)
+				p.writeString(s)
+				p.nlcount = 0
+				p.lastTok = x
+			}
+
+		case Operator:
+			if x != 0 {
+				p.flush(_Operator)
+				p.writeString(x.String())
+			}
+
+		case ctrlSymbol:
+			switch x {
+			case none, semi /*, comment*/ :
+				panic("unreachable")
+			case newline:
+				// TODO(gri) need to handle mandatory newlines after a //-style comment
+				if !p.linebreaks {
+					x = blank
+				}
+			}
+			p.addWhitespace(x, "")
+
+		// case *Comment: // comments are not Nodes
+		// 	p.addWhitespace(comment, x.Text)
+
+		default:
+			panic(fmt.Sprintf("unexpected argument %v (%T)", x, x))
+		}
+	}
+}
+
+func (p *printer) printNode(n Node) {
+	// ncom := *n.Comments()
+	// if ncom != nil {
+	// 	// TODO(gri) in general we cannot make assumptions about whether
+	// 	// a comment is a /*- or a //-style comment since the syntax
+	// 	// tree may have been manipulated. Need to make sure the correct
+	// 	// whitespace is emitted.
+	// 	for _, c := range ncom.Alone {
+	// 		p.print(c, newline)
+	// 	}
+	// 	for _, c := range ncom.Before {
+	// 		if c.Text == "" || lineComment(c.Text) {
+	// 			panic("unexpected empty line or //-style 'before' comment")
+	// 		}
+	// 		p.print(c, blank)
+	// 	}
+	// }
+
+	p.printRawNode(n)
+
+	// if ncom != nil && len(ncom.After) > 0 {
+	// 	for i, c := range ncom.After {
+	// 		if i+1 < len(ncom.After) {
+	// 			if c.Text == "" || lineComment(c.Text) {
+	// 				panic("unexpected empty line or //-style non-final 'after' comment")
+	// 			}
+	// 		}
+	// 		p.print(blank, c)
+	// 	}
+	// 	//p.print(newline)
+	// }
+}
+
+func (p *printer) printRawNode(n Node) {
+	switch n := n.(type) {
+	case nil:
+		// we should not reach here but don't crash
+
+	// expressions and types
+	case *BadExpr:
+		p.print(_Name, "<bad expr>")
+
+	case *Name:
+		p.print(_Name, n.Value) // _Name requires actual value following immediately
+
+	case *BasicLit:
+		p.print(_Name, n.Value) // _Name requires actual value following immediately
+
+	case *FuncLit:
+		p.print(n.Type, blank, n.Body)
+
+	case *CompositeLit:
+		if n.Type != nil {
+			p.print(n.Type)
+		}
+		p.print(_Lbrace)
+		if n.NKeys > 0 && n.NKeys == len(n.ElemList) {
+			p.printExprLines(n.ElemList)
+		} else {
+			p.printExprList(n.ElemList)
+		}
+		p.print(_Rbrace)
+
+	case *ParenExpr:
+		p.print(_Lparen, n.X, _Rparen)
+
+	case *SelectorExpr:
+		p.print(n.X, _Dot, n.Sel)
+
+	case *IndexExpr:
+		p.print(n.X, _Lbrack, n.Index, _Rbrack)
+
+	case *SliceExpr:
+		p.print(n.X, _Lbrack)
+		if i := n.Index[0]; i != nil {
+			p.printNode(i)
+		}
+		p.print(_Colon)
+		if j := n.Index[1]; j != nil {
+			p.printNode(j)
+		}
+		if k := n.Index[2]; k != nil {
+			p.print(_Colon, k)
+		}
+		p.print(_Rbrack)
+
+	case *AssertExpr:
+		p.print(n.X, _Dot, _Lparen, n.Type, _Rparen)
+
+	case *TypeSwitchGuard:
+		if n.Lhs != nil {
+			p.print(n.Lhs, blank, _Define, blank)
+		}
+		p.print(n.X, _Dot, _Lparen, _Type, _Rparen)
+
+	case *CallExpr:
+		p.print(n.Fun, _Lparen)
+		p.printExprList(n.ArgList)
+		if n.HasDots {
+			p.print(_DotDotDot)
+		}
+		p.print(_Rparen)
+
+	case *Operation:
+		if n.Y == nil {
+			// unary expr
+			p.print(n.Op)
+			// if n.Op == lexical.Range {
+			// 	p.print(blank)
+			// }
+			p.print(n.X)
+		} else {
+			// binary expr
+			// TODO(gri) eventually take precedence into account
+			// to control possibly missing parentheses
+			p.print(n.X, blank, n.Op, blank, n.Y)
+		}
+
+	case *KeyValueExpr:
+		p.print(n.Key, _Colon, blank, n.Value)
+
+	case *ListExpr:
+		p.printExprList(n.ElemList)
+
+	case *ArrayType:
+		var len interface{} = _DotDotDot
+		if n.Len != nil {
+			len = n.Len
+		}
+		p.print(_Lbrack, len, _Rbrack, n.Elem)
+
+	case *SliceType:
+		p.print(_Lbrack, _Rbrack, n.Elem)
+
+	case *DotsType:
+		p.print(_DotDotDot, n.Elem)
+
+	case *StructType:
+		p.print(_Struct)
+		if len(n.FieldList) > 0 && p.linebreaks {
+			p.print(blank)
+		}
+		p.print(_Lbrace)
+		if len(n.FieldList) > 0 {
+			p.print(newline, indent)
+			p.printFieldList(n.FieldList, n.TagList)
+			p.print(outdent, newline)
+		}
+		p.print(_Rbrace)
+
+	case *FuncType:
+		p.print(_Func)
+		p.printSignature(n)
+
+	case *InterfaceType:
+		p.print(_Interface)
+		if len(n.MethodList) > 0 && p.linebreaks {
+			p.print(blank)
+		}
+		p.print(_Lbrace)
+		if len(n.MethodList) > 0 {
+			p.print(newline, indent)
+			p.printMethodList(n.MethodList)
+			p.print(outdent, newline)
+		}
+		p.print(_Rbrace)
+
+	case *MapType:
+		p.print(_Map, _Lbrack, n.Key, _Rbrack, n.Value)
+
+	case *ChanType:
+		if n.Dir == RecvOnly {
+			p.print(_Arrow)
+		}
+		p.print(_Chan)
+		if n.Dir == SendOnly {
+			p.print(_Arrow)
+		}
+		p.print(blank, n.Elem)
+
+	// statements
+	case *DeclStmt:
+		p.printDecl(n.DeclList)
+
+	case *EmptyStmt:
+		// nothing to print
+
+	case *LabeledStmt:
+		p.print(outdent, n.Label, _Colon, indent, newline, n.Stmt)
+
+	case *ExprStmt:
+		p.print(n.X)
+
+	case *SendStmt:
+		p.print(n.Chan, blank, _Arrow, blank, n.Value)
+
+	case *AssignStmt:
+		p.print(n.Lhs)
+		if n.Rhs == ImplicitOne {
+			// TODO(gri) This is going to break the mayCombine
+			//           check once we enable that again.
+			p.print(n.Op, n.Op) // ++ or --
+		} else {
+			p.print(blank, n.Op, _Assign, blank)
+			p.print(n.Rhs)
+		}
+
+	case *CallStmt:
+		p.print(n.Tok, blank, n.Call)
+
+	case *ReturnStmt:
+		p.print(_Return)
+		if n.Results != nil {
+			p.print(blank, n.Results)
+		}
+
+	case *BranchStmt:
+		p.print(n.Tok)
+		if n.Label != nil {
+			p.print(blank, n.Label)
+		}
+
+	case *BlockStmt:
+		p.print(_Lbrace)
+		if len(n.List) > 0 {
+			p.print(newline, indent)
+			p.printStmtList(n.List, true)
+			p.print(outdent, newline)
+		}
+		p.print(_Rbrace)
+
+	case *IfStmt:
+		p.print(_If, blank)
+		if n.Init != nil {
+			p.print(n.Init, _Semi, blank)
+		}
+		p.print(n.Cond, blank, n.Then)
+		if n.Else != nil {
+			p.print(blank, _Else, blank, n.Else)
+		}
+
+	case *SwitchStmt:
+		p.print(_Switch, blank)
+		if n.Init != nil {
+			p.print(n.Init, _Semi, blank)
+		}
+		if n.Tag != nil {
+			p.print(n.Tag, blank)
+		}
+		p.printSwitchBody(n.Body)
+
+	case *SelectStmt:
+		p.print(_Select, blank) // for now
+		p.printSelectBody(n.Body)
+
+	case *RangeClause:
+		if n.Lhs != nil {
+			tok := _Assign
+			if n.Def {
+				tok = _Define
+			}
+			p.print(n.Lhs, blank, tok, blank)
+		}
+		p.print(_Range, blank, n.X)
+
+	case *ForStmt:
+		p.print(_For, blank)
+		if n.Init == nil && n.Post == nil {
+			if n.Cond != nil {
+				p.print(n.Cond, blank)
+			}
+		} else {
+			if n.Init != nil {
+				p.print(n.Init)
+				// TODO(gri) clean this up
+				if _, ok := n.Init.(*RangeClause); ok {
+					p.print(blank, n.Body)
+					break
+				}
+			}
+			p.print(_Semi, blank)
+			if n.Cond != nil {
+				p.print(n.Cond)
+			}
+			p.print(_Semi, blank)
+			if n.Post != nil {
+				p.print(n.Post, blank)
+			}
+		}
+		p.print(n.Body)
+
+	case *ImportDecl:
+		if n.Group == nil {
+			p.print(_Import, blank)
+		}
+		if n.LocalPkgName != nil {
+			p.print(n.LocalPkgName, blank)
+		}
+		p.print(n.Path)
+
+	case *ConstDecl:
+		if n.Group == nil {
+			p.print(_Const, blank)
+		}
+		p.printNameList(n.NameList)
+		if n.Type != nil {
+			p.print(blank, n.Type)
+		}
+		if n.Values != nil {
+			p.print(blank, _Assign, blank, n.Values)
+		}
+
+	case *TypeDecl:
+		if n.Group == nil {
+			p.print(_Type, blank)
+		}
+		p.print(n.Name, blank)
+		if n.Alias {
+			p.print(_Assign, blank)
+		}
+		p.print(n.Type)
+
+	case *VarDecl:
+		if n.Group == nil {
+			p.print(_Var, blank)
+		}
+		p.printNameList(n.NameList)
+		if n.Type != nil {
+			p.print(blank, n.Type)
+		}
+		if n.Values != nil {
+			p.print(blank, _Assign, blank, n.Values)
+		}
+
+	case *FuncDecl:
+		p.print(_Func, blank)
+		if r := n.Recv; r != nil {
+			p.print(_Lparen)
+			if r.Name != nil {
+				p.print(r.Name, blank)
+			}
+			p.printNode(r.Type)
+			p.print(_Rparen, blank)
+		}
+		p.print(n.Name)
+		p.printSignature(n.Type)
+		if n.Body != nil {
+			p.print(blank, n.Body)
+		}
+
+	case *printGroup:
+		p.print(n.Tok, blank, _Lparen)
+		if len(n.Decls) > 0 {
+			p.print(newline, indent)
+			for _, d := range n.Decls {
+				p.printNode(d)
+				p.print(_Semi, newline)
+			}
+			p.print(outdent)
+		}
+		p.print(_Rparen)
+
+	// files
+	case *File:
+		p.print(_Package, blank, n.PkgName)
+		if len(n.DeclList) > 0 {
+			p.print(_Semi, newline, newline)
+			p.printDeclList(n.DeclList)
+		}
+
+	default:
+		panic(fmt.Sprintf("syntax.Iterate: unexpected node type %T", n))
+	}
+}
+
+func (p *printer) printFields(fields []*Field, tags []*BasicLit, i, j int) {
+	if i+1 == j && fields[i].Name == nil {
+		// anonymous field
+		p.printNode(fields[i].Type)
+	} else {
+		for k, f := range fields[i:j] {
+			if k > 0 {
+				p.print(_Comma, blank)
+			}
+			p.printNode(f.Name)
+		}
+		p.print(blank)
+		p.printNode(fields[i].Type)
+	}
+	if i < len(tags) && tags[i] != nil {
+		p.print(blank)
+		p.printNode(tags[i])
+	}
+}
+
+func (p *printer) printFieldList(fields []*Field, tags []*BasicLit) {
+	i0 := 0
+	var typ Expr
+	for i, f := range fields {
+		if f.Name == nil || f.Type != typ {
+			if i0 < i {
+				p.printFields(fields, tags, i0, i)
+				p.print(_Semi, newline)
+				i0 = i
+			}
+			typ = f.Type
+		}
+	}
+	p.printFields(fields, tags, i0, len(fields))
+}
+
+func (p *printer) printMethodList(methods []*Field) {
+	for i, m := range methods {
+		if i > 0 {
+			p.print(_Semi, newline)
+		}
+		if m.Name != nil {
+			p.printNode(m.Name)
+			p.printSignature(m.Type.(*FuncType))
+		} else {
+			p.printNode(m.Type)
+		}
+	}
+}
+
+func (p *printer) printNameList(list []*Name) {
+	for i, x := range list {
+		if i > 0 {
+			p.print(_Comma, blank)
+		}
+		p.printNode(x)
+	}
+}
+
+func (p *printer) printExprList(list []Expr) {
+	for i, x := range list {
+		if i > 0 {
+			p.print(_Comma, blank)
+		}
+		p.printNode(x)
+	}
+}
+
+func (p *printer) printExprLines(list []Expr) {
+	if len(list) > 0 {
+		p.print(newline, indent)
+		for _, x := range list {
+			p.print(x, _Comma, newline)
+		}
+		p.print(outdent)
+	}
+}
+
+func groupFor(d Decl) (token, *Group) {
+	switch d := d.(type) {
+	case *ImportDecl:
+		return _Import, d.Group
+	case *ConstDecl:
+		return _Const, d.Group
+	case *TypeDecl:
+		return _Type, d.Group
+	case *VarDecl:
+		return _Var, d.Group
+	case *FuncDecl:
+		return _Func, nil
+	default:
+		panic("unreachable")
+	}
+}
+
+type printGroup struct {
+	node
+	Tok   token
+	Decls []Decl
+}
+
+func (p *printer) printDecl(list []Decl) {
+	tok, group := groupFor(list[0])
+
+	if group == nil {
+		if len(list) != 1 {
+			panic("unreachable")
+		}
+		p.printNode(list[0])
+		return
+	}
+
+	// if _, ok := list[0].(*EmptyDecl); ok {
+	// 	if len(list) != 1 {
+	// 		panic("unreachable")
+	// 	}
+	// 	// TODO(gri) if there are comments inside the empty
+	// 	// group, we may need to keep the list non-nil
+	// 	list = nil
+	// }
+
+	// printGroup is here for consistent comment handling
+	// (this is not yet used)
+	var pg printGroup
+	// *pg.Comments() = *group.Comments()
+	pg.Tok = tok
+	pg.Decls = list
+	p.printNode(&pg)
+}
+
+func (p *printer) printDeclList(list []Decl) {
+	i0 := 0
+	var tok token
+	var group *Group
+	for i, x := range list {
+		if s, g := groupFor(x); g == nil || g != group {
+			if i0 < i {
+				p.printDecl(list[i0:i])
+				p.print(_Semi, newline)
+				// print empty line between different declaration groups,
+				// different kinds of declarations, or between functions
+				if g != group || s != tok || s == _Func {
+					p.print(newline)
+				}
+				i0 = i
+			}
+			tok, group = s, g
+		}
+	}
+	p.printDecl(list[i0:])
+}
+
+func (p *printer) printSignature(sig *FuncType) {
+	p.printParameterList(sig.ParamList)
+	if list := sig.ResultList; list != nil {
+		p.print(blank)
+		if len(list) == 1 && list[0].Name == nil {
+			p.printNode(list[0].Type)
+		} else {
+			p.printParameterList(list)
+		}
+	}
+}
+
+func (p *printer) printParameterList(list []*Field) {
+	p.print(_Lparen)
+	if len(list) > 0 {
+		for i, f := range list {
+			if i > 0 {
+				p.print(_Comma, blank)
+			}
+			if f.Name != nil {
+				p.printNode(f.Name)
+				if i+1 < len(list) {
+					f1 := list[i+1]
+					if f1.Name != nil && f1.Type == f.Type {
+						continue // no need to print type
+					}
+				}
+				p.print(blank)
+			}
+			p.printNode(f.Type)
+		}
+	}
+	p.print(_Rparen)
+}
+
+func (p *printer) printStmtList(list []Stmt, braces bool) {
+	for i, x := range list {
+		p.print(x, _Semi)
+		if i+1 < len(list) {
+			p.print(newline)
+		} else if braces {
+			// Print an extra semicolon if the last statement is
+			// an empty statement and we are in a braced block
+			// because one semicolon is automatically removed.
+			if _, ok := x.(*EmptyStmt); ok {
+				p.print(x, _Semi)
+			}
+		}
+	}
+}
+
+func (p *printer) printSwitchBody(list []*CaseClause) {
+	p.print(_Lbrace)
+	if len(list) > 0 {
+		p.print(newline)
+		for i, c := range list {
+			p.printCaseClause(c, i+1 == len(list))
+			p.print(newline)
+		}
+	}
+	p.print(_Rbrace)
+}
+
+func (p *printer) printSelectBody(list []*CommClause) {
+	p.print(_Lbrace)
+	if len(list) > 0 {
+		p.print(newline)
+		for i, c := range list {
+			p.printCommClause(c, i+1 == len(list))
+			p.print(newline)
+		}
+	}
+	p.print(_Rbrace)
+}
+
+func (p *printer) printCaseClause(c *CaseClause, braces bool) {
+	if c.Cases != nil {
+		p.print(_Case, blank, c.Cases)
+	} else {
+		p.print(_Default)
+	}
+	p.print(_Colon)
+	if len(c.Body) > 0 {
+		p.print(newline, indent)
+		p.printStmtList(c.Body, braces)
+		p.print(outdent)
+	}
+}
+
+func (p *printer) printCommClause(c *CommClause, braces bool) {
+	if c.Comm != nil {
+		p.print(_Case, blank)
+		p.print(c.Comm)
+	} else {
+		p.print(_Default)
+	}
+	p.print(_Colon)
+	if len(c.Body) > 0 {
+		p.print(newline, indent)
+		p.printStmtList(c.Body, braces)
+		p.print(outdent)
+	}
+}