printer:

- prepare for generation of HTML id tags and links
- do HTML-escaping in central print routine
- move tabwriter setup into printer
- fixed various TODOs

godoc:
- removed tabwriter setup, need for various HTML-escaping

R=rsc
DELTA=210  (107 added, 36 deleted, 67 changed)
OCL=32612
CL=32616

src/cmd/godoc/godoc.go

@@ -47,7 +47,6 @@ import (
 	"strings";
 	"sync";
 	"syscall";
-	"tabwriter";
 	"template";
 	"time";
 )
@@ -125,11 +124,6 @@ func isPkgDir(dir *os.Dir) bool {
 }
 
 
-func makeTabwriter(writer io.Writer) *tabwriter.Writer {
-	return tabwriter.NewWriter(writer, *tabwidth, 1, byte(' '), 0);
-}
-
-
 // ----------------------------------------------------------------------------
 // Parsing
 
@@ -201,55 +195,66 @@ func parse(path string, mode uint) (*ast.File, *parseErrors) {
 // ----------------------------------------------------------------------------
 // Templates
 
-// Return text for an AST node.
+// Write an AST-node to w; optionally html-escaped.
-func nodeText(node interface{}) []byte {
+func writeNode(w io.Writer, node interface{}, html bool) {
-	var buf bytes.Buffer;
+	mode := printer.UseSpaces;
-	tw := makeTabwriter(&buf);
+	if html {
-	printer.Fprint(tw, node, 0);
+		mode |= printer.GenHTML;
-	tw.Flush();
+	}
-	return buf.Data();
+	printer.Fprint(w, node, mode, *tabwidth);
 }
 
 
-// Convert x, whatever it is, to text form.
+// Write text to w; optionally html-escaped.
-func toText(x interface{}) []byte {
+func writeText(w io.Writer, text []byte, html bool) {
-	type Stringer interface { String() string }
+	if html {
+		template.HtmlEscape(w, text);
+		return;
+	}
+	w.Write(text);
+}
 
+
+// Write anything to w; optionally html-escaped.
+func writeAny(w io.Writer, x interface{}, html bool) {
 	switch v := x.(type) {
 	case []byte:
-		return v;
+		writeText(w, v, html);
 	case string:
-		return strings.Bytes(v);
+		writeText(w, strings.Bytes(v), html);
 	case ast.Decl:
-		return nodeText(v);
+		writeNode(w, v, html);
 	case ast.Expr:
-		return nodeText(v);
+		writeNode(w, v, html);
-	case Stringer:
+	default:
-		// last resort (AST nodes get a String method
+		if html {
-		// from token.Position - don't call that one)
+			var buf bytes.Buffer;
-		return strings.Bytes(v.String());
+			fmt.Fprint(&buf, x);
+			writeText(w, buf.Data(), true);
+		} else {
+			fmt.Fprint(w, x);
+		}
 	}
-	var buf bytes.Buffer;
-	fmt.Fprint(&buf, x);
-	return buf.Data();
 }
 
 
 // Template formatter for "html" format.
 func htmlFmt(w io.Writer, x interface{}, format string) {
-	template.HtmlEscape(w, toText(x));
+	writeAny(w, x, true);
 }
 
 
 // Template formatter for "html-comment" format.
 func htmlCommentFmt(w io.Writer, x interface{}, format string) {
-	doc.ToHtml(w, toText(x));
+	var buf bytes.Buffer;
+	writeAny(&buf, x, false);
+	doc.ToHtml(w, buf.Data());
 }
 
 
 // Template formatter for "" (default) format.
 func textFmt(w io.Writer, x interface{}, format string) {
-	w.Write(toText(x));
+	writeAny(w, x, false);
 }
 
 
@@ -337,7 +342,7 @@ func serveGoSource(c *http.Conn, name string) {
 
 	var buf bytes.Buffer;
 	fmt.Fprintln(&buf, "<pre>");
-	template.HtmlEscape(&buf, nodeText(prog));
+	writeNode(&buf, prog, true);
 	fmt.Fprintln(&buf, "</pre>");
 
 	servePage(c, name + " - Go source", buf.Data());

src/cmd/gofmt/gofmt.go

@@ -16,7 +16,6 @@ import (
 	pathutil "path";
 	"sort";
 	"strings";
-	"tabwriter";
 )
 
 
@@ -34,8 +33,9 @@ var (
 	exports = flag.Bool("x", false, "show exports only");
 
 	// layout control
-	tabwidth = flag.Int("tabwidth", 4, "tab width");
+	tabwidth = flag.Int("tabwidth", 8, "tab width");
-	usetabs = flag.Bool("tabs", false, "align with tabs instead of blanks");
+	rawformat = flag.Bool("rawformat", false, "do not use a tabwriter");
+	usespaces = flag.Bool("spaces", false, "align with blanks instead of tabs");
 	optcommas = flag.Bool("optcommas", false, "print optional commas");
 	optsemis = flag.Bool("optsemis", false, "print optional semicolons");
 )
@@ -104,6 +104,12 @@ func getPackage(path string) (*ast.Package, os.Error) {
 
 func printerMode() uint {
 	mode := uint(0);
+	if *rawformat {
+		mode |= printer.RawFormat;
+	}
+	if *usespaces {
+		mode |= printer.UseSpaces;
+	}
 	if *optcommas {
 		mode |= printer.OptCommas;
 	}
@@ -114,15 +120,6 @@ func printerMode() uint {
 }
 
 
-func makeTabwriter(writer io.Writer) *tabwriter.Writer {
-	padchar := byte(' ');
-	if *usetabs {
-		padchar = '\t';
-	}
-	return tabwriter.NewWriter(writer, *tabwidth, 1, padchar, 0);
-}
-
-
 func main() {
 	flag.Usage = usage;
 	flag.Parse();
@@ -144,15 +141,21 @@ func main() {
 	}
 
 	if !*silent {
-		w := makeTabwriter(os.Stdout);
 		if *exports {
 			ast.PackageExports(pkg);
-			printer.Fprint(w, ast.MergePackageFiles(pkg), printerMode());  // ignore errors
+			_, err := printer.Fprint(os.Stdout, ast.MergePackageFiles(pkg), printerMode(), *tabwidth);
+			if err != nil {
+				fmt.Fprint(os.Stderr, err);
+				os.Exit(2);
+			}
 		} else {
 			for _, src := range pkg.Files {
-				printer.Fprint(w, src, printerMode());  // ignore errors
+				_, err := printer.Fprint(os.Stdout, src, printerMode(), *tabwidth);
+				if err != nil {
+					fmt.Fprint(os.Stderr, err);
+					os.Exit(2);
+				}
 			}
 		}
-		w.Flush();
 	}
 }

src/pkg/Make.deps

@@ -22,7 +22,7 @@ fmt.install: io.install os.install reflect.install strconv.install utf8.install
 go/ast.install: go/token.install unicode.install utf8.install
 go/doc.install: container/vector.install fmt.install go/ast.install go/token.install io.install once.install regexp.install sort.install strings.install template.install
 go/parser.install: bytes.install container/vector.install fmt.install go/ast.install go/scanner.install go/token.install io.install os.install path.install strings.install
-go/printer.install: fmt.install go/ast.install go/token.install io.install os.install reflect.install strings.install
+go/printer.install: fmt.install go/ast.install go/token.install io.install os.install reflect.install strings.install tabwriter.install
 go/scanner.install: bytes.install container/vector.install fmt.install go/token.install io.install os.install sort.install strconv.install unicode.install utf8.install
 go/token.install: fmt.install strconv.install
 gob.install: bytes.install fmt.install io.install math.install os.install reflect.install strings.install sync.install unicode.install

src/pkg/go/printer/printer.go

@@ -13,6 +13,7 @@ import (
 	"os";
 	"reflect";
 	"strings";
+	"tabwriter";
 )
 
 
@@ -26,7 +27,10 @@ const (
 // to Fprint via the mode parameter.
 //
 const (
-	OptCommas = 1 << iota;  // print optional commas
+	GenHTML uint = 1 << iota;  // generate HTML
+	RawFormat;  // do not use a tabwriter; if set, UseSpaces is ignored
+	UseSpaces;  // use spaces instead of tabs for indentation and alignment
+	OptCommas;  // print optional commas
 	OptSemis;  // print optional semicolons
 )
 
@@ -41,6 +45,15 @@ const (
 )
 
 
+var (
+	tabs = [...]byte{'\t', '\t', '\t', '\t', '\t', '\t', '\t', '\t'};
+	newlines = [...]byte{'\n', '\n', '\n', '\n', '\n', '\n', '\n', '\n'};  // more than maxNewlines
+	ampersand = strings.Bytes("&amp;");
+	lessthan = strings.Bytes("&lt;");
+	greaterthan = strings.Bytes("&gt;");
+)
+
+
 type printer struct {
 	// configuration (does not change after initialization)
 	output io.Writer;
@@ -70,8 +83,7 @@ func (p *printer) init(output io.Writer, mode uint) {
 
 
 // Writing to p.output is done with write0 which also handles errors.
-// It should only be called by write and debug routines which are not
+// Does not indent after newlines, or HTML-escape, or update p.pos.
-// supposed to update the p.pos estimation.
 //
 func (p *printer) write0(data []byte) {
 	n, err := p.output.Write(data);
@@ -85,22 +97,55 @@ func (p *printer) write0(data []byte) {
 func (p *printer) write(data []byte) {
 	i0 := 0;
 	for i, b := range data {
-		if b == '\n' || b == '\f' {
+		switch b {
-			// write segment ending in a newline/formfeed followed by indentation
+		case '\n', '\f':
-			// TODO(gri) should convert '\f' into '\n' if the output is not going
+			// write segment ending in b followed by indentation
-			//           through tabwriter
+			if p.mode & RawFormat != 0 && b == '\f' {
-			p.write0(data[i0 : i+1]);
+				// no tabwriter - convert last byte into a newline
-			// TODO(gri) should not write indentation is there is nothing else
+				p.write0(data[i0 : i]);
-			//           on the line
+				p.write0(newlines[0 : 1]);
-			for j := p.indent; j > 0; j-- {
+			} else {
-				p.write0([]byte{'\t'});  // TODO(gri) don't do allocation in every iteration
+				p.write0(data[i0 : i+1]);
 			}
-			i0 = i+1;
+
+			// write indentation
+			// TODO(gri) should not write indentation if there is nothing else
+			//           on the line
+			j := p.indent;
+			for ; j > len(tabs); j -= len(tabs) {
+				p.write0(&tabs);
+			}
+			p.write0(tabs[0 : j]);
 
 			// update p.pos
 			p.pos.Offset += i+1 - i0 + p.indent;
 			p.pos.Line++;
 			p.pos.Column = p.indent + 1;
+
+			// next segment start
+			i0 = i+1;
+
+		case '&', '<', '>':
+			if p.mode & GenHTML != 0 {
+				// write segment ending in b
+				p.write0(data[i0 : i]);
+
+				// write HTML-escaped b
+				var esc []byte;
+				switch b {
+				case '&': esc = ampersand;
+				case '<': esc = lessthan;
+				case '>': esc = greaterthan;
+				}
+				p.write0(esc);
+
+				// update p.pos
+				p.pos.Offset += i+1 - i0;
+				p.pos.Column += i+1 - i0;
+
+				// next segment start
+				i0 = i+1;
+			}
 		}
 	}
 
@@ -114,33 +159,29 @@ func (p *printer) write(data []byte) {
 }
 
 
-// TODO(gri) Don't go through write and make this more efficient.
-func (p *printer) writeByte(b byte) {
-	p.write([]byte{b});
-}
-
-
 func (p *printer) writeNewlines(n int) {
-	if n > maxNewlines {
+	if n > 0 {
-		n = maxNewlines;
+		if n > maxNewlines {
+			n = maxNewlines;
+		}
+		p.write(newlines[0 : n]);
 	}
-	for ; n > 0; n-- {
-		p.writeByte('\n');
-	}
-}
-
-
-func (p *printer) writePos(pos token.Position) {
-	// use write0 so not to disturb the p.pos update by write
-	p.write0(strings.Bytes(fmt.Sprintf("[%d:%d]", pos.Line, pos.Column)));
 }
 
 
 func (p *printer) writeItem(pos token.Position, data []byte) {
 	p.pos = pos;
 	if debug {
-		p.writePos(pos);
+		// do not update p.pos - use write0
+		p.write0(strings.Bytes(fmt.Sprintf("[%d:%d]", pos.Line, pos.Column)));
 	}
+	// TODO(gri) Enable once links are generated.
+	/*
+	if p.mode & GenHTML != 0 {
+		// do not HTML-escape or update p.pos - use write0
+		p.write0(strings.Bytes(fmt.Sprintf("<a id=%x></a>", pos.Offset)));
+	}
+	*/
 	p.write(data);
 	p.prev = p.pos;
 }
@@ -172,7 +213,7 @@ func (p *printer) writeComment(comment *ast.Comment) {
 		n := comment.Pos().Line - p.prev.Line;
 		if n == 0 {
 			// comment on the same line as previous item; separate with tab
-			p.writeByte('\t');
+			p.write(tabs[0 : 1]);
 		} else {
 			// comment on a different line; separate with newlines
 			p.writeNewlines(n);
@@ -239,10 +280,16 @@ func (p *printer) intersperseComments(next token.Position) {
 
 
 func (p *printer) writeWhitespace() {
+	var a [len(p.buffer)]byte;
 	for i := 0; i < p.buflen; i++ {
-		p.writeByte(byte(p.buffer[i]));
+		a[i] = byte(p.buffer[i]);
 	}
+
+	var b []byte = &a;
+	b = b[0 : p.buflen];
 	p.buflen = 0;
+
+	p.write(b);
 }
 
 
@@ -254,7 +301,7 @@ func (p *printer) writeWhitespace() {
 // Whitespace is accumulated until a non-whitespace token appears. Any
 // comments that need to appear before that token are printed first,
 // taking into account the amount and structure of any pending white-
-// space for best commemnt placement. Then, any leftover whitespace is
+// space for best comment placement. Then, any leftover whitespace is
 // printed, followed by the actual token.
 //
 func (p *printer) print(args ...) {
@@ -930,8 +977,8 @@ func (p *printer) spec(spec ast.Spec) (comment *ast.CommentGroup, optSemi bool)
 		if s.Name != nil {
 			p.expr(s.Name);
 		}
-		// TODO fix for longer package names
+		p.print(tab);
-		p.print(tab, s.Path[0].Pos(), s.Path[0].Value);
+		p.expr(&ast.StringList{s.Path});
 		comment = s.Comment;
 
 	case *ast.ValueSpec:
@@ -1057,14 +1104,28 @@ func (p *printer) file(src *ast.File) {
 
 // Fprint "pretty-prints" an AST node to output and returns the number of
 // bytes written, and an error, if any. The node type must be *ast.File,
-// or assignment-compatible to ast.Expr, ast.Decl, or ast.Stmt. Printing is
+// or assignment-compatible to ast.Expr, ast.Decl, or ast.Stmt. Printing
-// controlled by the mode parameter. For best results, the output should be
+// is controlled by the mode and tabwidth parameters.
-// a tabwriter.Writer.
 //
-func Fprint(output io.Writer, node interface{}, mode uint) (int, os.Error) {
+func Fprint(output io.Writer, node interface{}, mode uint, tabwidth int) (int, os.Error) {
+	// setup tabwriter if needed and redirect output
+	var tw *tabwriter.Writer;
+	if mode & RawFormat == 0 {
+		padchar := byte('\t');
+		if mode & UseSpaces != 0 {
+			padchar = ' ';
+		}
+		var twmode uint;
+		if mode & GenHTML != 0 {
+			twmode = tabwriter.FilterHTML;
+		}
+		tw = tabwriter.NewWriter(output, tabwidth, 1, padchar, twmode);
+		output = tw;
+	}
+
+	// setup printer and print node
 	var p printer;
 	p.init(output, mode);
-
 	go func() {
 		switch n := node.(type) {
 		case ast.Expr:
@@ -1085,5 +1146,10 @@ func Fprint(output io.Writer, node interface{}, mode uint) (int, os.Error) {
 	}();
 	err := <-p.errors;  // wait for completion of goroutine
 
+	// flush tabwriter, if any
+	if tw != nil {
+		tw.Flush();  // ignore errors
+	}
+
 	return p.written, err;
 }

src/pkg/go/printer/printer_test.go

@@ -13,7 +13,6 @@ import (
 	"go/printer";
 	"os";
 	"path";
-	"tabwriter";
 	"testing";
 )
 
@@ -21,8 +20,6 @@ import (
 const (
 	dataDir = "testdata";
 	tabwidth = 4;
-	padding = 1;
-	tabchar = '\t';
 )
 
 
@@ -54,9 +51,9 @@ func check(t *testing.T, source, golden string, exports bool) {
 
 	// format source
 	var buf bytes.Buffer;
-	w := tabwriter.NewWriter(&buf, tabwidth, padding, tabchar, 0);
+	if _, err := Fprint(&buf, prog, 0, tabwidth); err != nil {
-	Fprint(w, prog, 0);
+		t.Error(err);
-	w.Flush();
+	}
 	res := buf.Data();
 
 	// update golden files if necessary