- don't add "..." anonymous field to structs/interfaces if entries are stripped

- don't print any optional semicolons after declarations inside functions
- indicate non-exported fields/methods in exported types with a comment
  so that the "exported source" is legal Go code
- more tests

R=rsc
DELTA=300  (227 added, 25 deleted, 48 changed)
OCL=34697
CL=34730

src/pkg/go/ast/ast.go

@@ -83,12 +83,12 @@ type CommentGroup struct {
 // Expressions and types
 
 // A Field represents a Field declaration list in a struct type,
-// a method in an interface type, or a parameter/result declaration
+// a method list in an interface type, or a parameter/result declaration
 // in a signature.
 //
 type Field struct {
 	Doc *CommentGroup;  // associated documentation; or nil
-	Names []*Ident;  // field/method/parameter names; nil if anonymous field
+	Names []*Ident;  // field/method/parameter names; or nil if anonymous field
 	Type Expr;  // field/method/parameter type
 	Tag []*BasicLit;  // field tag; or nil
 	Comment *CommentGroup;  // line comments; or nil
@@ -249,8 +249,9 @@ type (
 	StructType struct {
 		token.Position;  // position of "struct" keyword
 		Lbrace token.Position;  // position of "{"
-		Fields []*Field;  // list of field declarations; nil if forward declaration
+		Fields []*Field;  // list of field declarations
 		Rbrace token.Position;  // position of "}"
+		Incomplete bool;  // true if (source) fields are missing in the Fields list
 	};
 
 	// Pointer types are represented via StarExpr nodes.
@@ -266,8 +267,9 @@ type (
 	InterfaceType struct {
 		token.Position;  // position of "interface" keyword
 		Lbrace token.Position;  // position of "{"
-		Methods []*Field; // list of methods; nil if forward declaration
+		Methods []*Field; // list of methods
 		Rbrace token.Position;  // position of "}"
+		Incomplete bool;  // true if (source) methods are missing in the Methods list
 	};
 
 	// A MapType node represents a map type.

src/pkg/go/ast/filter.go

@@ -4,9 +4,7 @@
 
 package ast
 
-import (
+import "go/token";
-	"go/token";
-)
 
 
 func filterIdentList(list []*Ident) []*Ident {
@@ -38,7 +36,7 @@ func isExportedType(typ Expr) bool {
 }
 
 
-func filterFieldList(list []*Field) []*Field {
+func filterFieldList(list []*Field, incomplete *bool) []*Field {
 	j := 0;
 	for _, f := range list {
 		exported := false;
@@ -51,7 +49,11 @@ func filterFieldList(list []*Field) []*Field {
 			// type information.)
 			exported = isExportedType(f.Type);
 		} else {
+			n := len(f.Names);
 			f.Names = filterIdentList(f.Names);
+			if len(f.Names) < n {
+				*incomplete = true;
+			}
 			exported = len(f.Names) > 0;
 		}
 		if exported {
@@ -60,11 +62,8 @@ func filterFieldList(list []*Field) []*Field {
 			j++;
 		}
 	}
-	if j > 0 && j < len(list) {
+	if j < len(list) {
-		// fields have been stripped but there is at least one left;
+		*incomplete = true;
-		// add a '...' anonymous field instead
-		list[j] = &Field{nil, nil, &Ellipsis{}, nil, nil};
-		j++;
 	}
 	return list[0 : j];
 }
@@ -84,30 +83,12 @@ func filterType(typ Expr) {
 	case *ArrayType:
 		filterType(t.Elt);
 	case *StructType:
-		// don't change if empty struct
+		t.Fields = filterFieldList(t.Fields, &t.Incomplete);
-		if len(t.Fields) > 0 {
-			t.Fields = filterFieldList(t.Fields);
-			if len(t.Fields) == 0 {
-				// all fields have been stripped - make look like forward-decl
-				t.Lbrace = noPos;
-				t.Fields = nil;
-				t.Rbrace = noPos;
-			}
-		}
 	case *FuncType:
 		filterParamList(t.Params);
 		filterParamList(t.Results);
 	case *InterfaceType:
-		// don't change if empty interface
+		t.Methods = filterFieldList(t.Methods, &t.Incomplete);
-		if len(t.Methods) > 0 {
-			t.Methods = filterFieldList(t.Methods);
-			if len(t.Methods) == 0 {
-				// all methods have been stripped - make look like forward-decl
-				t.Lbrace = noPos;
-				t.Methods = nil;
-				t.Rbrace = noPos;
-			}
-		}
 	case *MapType:
 		filterType(t.Key);
 		filterType(t.Value);

src/pkg/go/parser/parser.go

@@ -512,7 +512,7 @@ func (p *parser) parseStructType() *ast.StructType {
 		fields[i] = list.At(i).(*ast.Field);
 	}
 
-	return &ast.StructType{pos, lbrace, fields, rbrace};
+	return &ast.StructType{pos, lbrace, fields, rbrace, false};
 }
 
 
@@ -720,7 +720,7 @@ func (p *parser) parseInterfaceType() *ast.InterfaceType {
 		methods[i] = list.At(i).(*ast.Field);
 	}
 
-	return &ast.InterfaceType{pos, lbrace, methods, rbrace};
+	return &ast.InterfaceType{pos, lbrace, methods, rbrace, false};
 }
 
 

src/pkg/go/printer/printer.go

@@ -550,7 +550,8 @@ func (p *printer) parameters(list []*ast.Field) {
 }
 
 
-func (p *printer) signature(params, result []*ast.Field) {
+// Returns true if a separating semicolon is optional.
+func (p *printer) signature(params, result []*ast.Field) (optSemi bool) {
 	p.parameters(params);
 	if result != nil {
 		p.print(blank);
@@ -559,29 +560,35 @@ func (p *printer) signature(params, result []*ast.Field) {
 			// single anonymous result; no ()'s unless it's a function type
 			f := result[0];
 			if _, isFtyp := f.Type.(*ast.FuncType); !isFtyp {
-				p.expr(f.Type);
+				optSemi = p.expr(f.Type);
 				return;
 			}
 		}
 
 		p.parameters(result);
 	}
+	return;
 }
 
 
-// Returns true if the field list ends in a closing brace.
+func incompleteMsg(isInterface bool) string {
-func (p *printer) fieldList(lbrace token.Position, list []*ast.Field, rbrace token.Position, isInterface bool) bool {
+	if isInterface {
-	if list == nil {
+		return "// contains unexported methods";
-		// forward declaration
-		// TODO(gri) remove this logic once godoc doesn't produce field
-		//           lists that resemble forward declarations anymore
-		return false;  // no {}'s
 	}
+	return "// contains unexported fields";
+}
 
+
+func (p *printer) fieldList(lbrace token.Position, list []*ast.Field, rbrace token.Position, isIncomplete, isInterface bool) {
 	if len(list) == 0 {
-		// no blank between keyword and {} in this case
+		if isIncomplete {
-		p.print(lbrace, token.LBRACE, rbrace, token.RBRACE);
+			// all entries were stripped
-		return true;  // empty list with {}'s
+			p.print(blank, lbrace, token.LBRACE, +1, newline, incompleteMsg(isInterface), -1, newline, rbrace, token.RBRACE);
+		} else {
+			// no blank between keyword and {} in this case
+			p.print(lbrace, token.LBRACE, rbrace, token.RBRACE);
+		}
+		return;
 	}
 
 	p.print(blank, lbrace, token.LBRACE, +1, newline);
@@ -636,9 +643,13 @@ func (p *printer) fieldList(lbrace token.Position, list []*ast.Field, rbrace tok
 
 	p.print(token.SEMICOLON);
 	p.lineComment(lastComment);
-	p.print(-1, formfeed, rbrace, token.RBRACE);
 
-	return true;  // field list with {}'s
+	if isIncomplete {
+		// at least one entry printed, but some entries were stripped
+		p.print(newline, incompleteMsg(isInterface));
+	}
+
+	p.print(-1, formfeed, rbrace, token.RBRACE);
 }
 
 
@@ -715,6 +726,7 @@ func (p *printer) binaryExpr(x *ast.BinaryExpr, prec1 int) {
 }
 
 
+// Returns true if a separating semicolon is optional.
 func (p *printer) expr1(expr ast.Expr, prec1 int) (optSemi bool) {
 	p.print(expr.Pos());
 
@@ -735,7 +747,7 @@ func (p *printer) expr1(expr ast.Expr, prec1 int) (optSemi bool) {
 
 	case *ast.StarExpr:
 		p.print(token.MUL);
-		p.expr(x.X);
+		optSemi = p.expr(x.X);
 
 	case *ast.UnaryExpr:
 		const prec = token.UnaryPrec;
@@ -823,25 +835,27 @@ func (p *printer) expr1(expr ast.Expr, prec1 int) (optSemi bool) {
 			p.expr(x.Len);
 		}
 		p.print(token.RBRACK);
-		p.expr(x.Elt);
+		optSemi = p.expr(x.Elt);
 
 	case *ast.StructType:
 		p.print(token.STRUCT);
-		optSemi = p.fieldList(x.Lbrace, x.Fields, x.Rbrace, false);
+		p.fieldList(x.Lbrace, x.Fields, x.Rbrace, x.Incomplete, false);
+		optSemi = true;
 
 	case *ast.FuncType:
 		p.print(token.FUNC);
-		p.signature(x.Params, x.Results);
+		optSemi = p.signature(x.Params, x.Results);
 
 	case *ast.InterfaceType:
 		p.print(token.INTERFACE);
-		optSemi = p.fieldList(x.Lbrace, x.Methods, x.Rbrace, true);
+		p.fieldList(x.Lbrace, x.Methods, x.Rbrace, x.Incomplete, true);
+		optSemi = true;
 
 	case *ast.MapType:
 		p.print(token.MAP, token.LBRACK);
 		p.expr(x.Key);
 		p.print(token.RBRACK);
-		p.expr(x.Value);
+		optSemi = p.expr(x.Value);
 
 	case *ast.ChanType:
 		switch x.Dir {
@@ -853,7 +867,7 @@ func (p *printer) expr1(expr ast.Expr, prec1 int) (optSemi bool) {
 			p.print(token.CHAN, token.ARROW);
 		}
 		p.print(blank);
-		p.expr(x.Value);
+		optSemi = p.expr(x.Value);
 
 	default:
 		panic("unreachable");

src/pkg/go/printer/testdata/comments.go

@@ -15,9 +15,47 @@ const (
 )
 
 
-// The T type.
+// The SZ struct; it is empty.
-type T struct {
+type SZ struct {}
-	a, b, c int  // 3 fields
+
+// The S0 struct; no field is exported.
+type S0 struct {
+	int;
+	x, y, z int;  // 3 unexported fields
+}
+
+// The S1 struct; some fields are not exported.
+type S1 struct {
+	S0;
+	A, B, C float;  // 3 exported fields
+	D, b, c int;  // 2 unexported fields
+}
+
+// The S2 struct; all fields are exported.
+type S2 struct {
+	S1;
+	A, B, C float;  // 3 exported fields
+}
+
+// The IZ interface; it is empty.
+type SZ interface {}
+
+// The I0 interface; no method is exported.
+type I0 interface {
+	f, g (x int) int;  // 2 unexported methods
+}
+
+// The I1 interface; some methods are not exported.
+type I1 interface {
+	I0;
+	F, G (x float) float;  // 2 exported methods
+	H, g (x int) int;  // 1 unexported method
+}
+
+// The I2 interface; all methods are exported.
+type I1 interface {
+	I0;
+	F, G (x float) float;  // 2 exported methods
 }
 
 // This comment group should be separated

src/pkg/go/printer/testdata/comments.golden

@@ -15,9 +15,47 @@ const (
 )
 
 
-// The T type.
+// The SZ struct; it is empty.
-type T struct {
+type SZ struct{}
-	a, b, c	int;	// 3 fields
+
+// The S0 struct; no field is exported.
+type S0 struct {
+	int;
+	x, y, z	int;	// 3 unexported fields
+}
+
+// The S1 struct; some fields are not exported.
+type S1 struct {
+	S0;
+	A, B, C	float;	// 3 exported fields
+	D, b, c	int;	// 2 unexported fields
+}
+
+// The S2 struct; all fields are exported.
+type S2 struct {
+	S1;
+	A, B, C	float;	// 3 exported fields
+}
+
+// The IZ interface; it is empty.
+type SZ interface{}
+
+// The I0 interface; no method is exported.
+type I0 interface {
+	f, g	(x int) int;	// 2 unexported methods
+}
+
+// The I1 interface; some methods are not exported.
+type I1 interface {
+	I0;
+	F, G	(x float) float;	// 2 exported methods
+	H, g	(x int) int;		// 1 unexported method
+}
+
+// The I2 interface; all methods are exported.
+type I1 interface {
+	I0;
+	F, G	(x float) float;	// 2 exported methods
 }
 
 // This comment group should be separated

src/pkg/go/printer/testdata/comments.x

@@ -2,5 +2,46 @@
 //
 package main
 
-// The T type.
+// The SZ struct; it is empty.
-type T struct
+type SZ struct{}
+
+// The S0 struct; no field is exported.
+type S0 struct {
+	// contains unexported fields
+}
+
+// The S1 struct; some fields are not exported.
+type S1 struct {
+	S0;
+	A, B, C	float;	// 3 exported fields
+	D		int;	// 2 unexported fields
+	// contains unexported fields
+}
+
+// The S2 struct; all fields are exported.
+type S2 struct {
+	S1;
+	A, B, C	float;	// 3 exported fields
+}
+
+// The IZ interface; it is empty.
+type SZ interface{}
+
+// The I0 interface; no method is exported.
+type I0 interface {
+	// contains unexported methods
+}
+
+// The I1 interface; some methods are not exported.
+type I1 interface {
+	I0;
+	F, G	(x float) float;
+	H		(x int) int;
+	// contains unexported methods
+}
+
+// The I2 interface; all methods are exported.
+type I1 interface {
+	I0;
+	F, G	(x float) float;
+}

src/pkg/go/printer/testdata/declarations.go

@@ -7,10 +7,10 @@ package imports
 import "io"
 
 import (
-	a "io"
+	_ "io"
 )
 
-import a "io"
+import _ "io"
 
 import (
 	"io";
@@ -25,4 +25,50 @@ import (
 	c "i" "o";
 )
 
+func _() {
+	// the following decls need a semicolon at the end
+	type _ int;
+	type _ *int;
+	type _ []int;
+	type _ map[string]int;
+	type _ chan int;
+	type _ func() int;
+
+	var _ int;
+	var _ *int;
+	var _ []int;
+	var _ map[string]int;
+	var _ chan int;
+	var _ func() int;
+
+	// the following decls don't need a semicolon at the end
+	type _ struct{}
+	type _ *struct{}
+	type _ []struct{}
+	type _ map[string]struct{}
+	type _ chan struct{}
+	type _ func() struct{}
+
+	type _ interface{}
+	type _ *interface{}
+	type _ []interface{}
+	type _ map[string]interface{}
+	type _ chan interface{}
+	type _ func() interface{}
+
+	var _ struct{}
+	var _ *struct{}
+	var _ []struct{}
+	var _ map[string]struct{}
+	var _ chan struct{}
+	var _ func() struct{}
+
+	var _ interface{}
+	var _ *interface{}
+	var _ []interface{}
+	var _ map[string]interface{}
+	var _ chan interface{}
+	var _ func() interface{}
+}
+
 // TODO(gri) add more test cases

src/pkg/go/printer/testdata/declarations.golden

@@ -7,10 +7,10 @@ package imports
 import "io"
 
 import (
-	a "io";
+	_ "io";
 )
 
-import a "io"
+import _ "io"
 
 import (
 	"io";
@@ -25,4 +25,46 @@ import (
 	c			"i" "o";
 )
 
+func _() {
+	// the following decls need a semicolon at the end
+	type _ int;
+	type _ *int;
+	type _ []int;
+	type _ map[string]int;
+	type _ chan int;
+	type _ func() int;
+	var _ int;
+	var _ *int;
+	var _ []int;
+	var _ map[string]int;
+	var _ chan int;
+	var _ func() int;
+	
+	// the following decls don't need a semicolon at the end
+	type _ struct{}
+	type _ *struct{}
+	type _ []struct{}
+	type _ map[string]struct{}
+	type _ chan struct{}
+	type _ func() struct{}
+	type _ interface{}
+	type _ *interface{}
+	type _ []interface{}
+	type _ map[string]interface{}
+	type _ chan interface{}
+	type _ func() interface{}
+	var _ struct{}
+	var _ *struct{}
+	var _ []struct{}
+	var _ map[string]struct{}
+	var _ chan struct{}
+	var _ func() struct{}
+	var _ interface{}
+	var _ *interface{}
+	var _ []interface{}
+	var _ map[string]interface{}
+	var _ chan interface{}
+	var _ func() interface{}
+}
+
 // TODO(gri) add more test cases