- factored out tabwriter a separate writer filter

(to be moved into std lib eventually)
- rewrote tabwriter to use byte buffers instead of strings
  (byte buffers to be moved into stdlib eventually)
- support for recent syntax changes
- no space printed after function name and before function parameters
- comments still disabled due to a known bug

R=r
OCL=19430
CL=19430

usr/gri/pretty/Makefile

@@ -32,7 +32,8 @@ parser.6:	 scanner.6 ast.6
 
 platform.6:	 utils.6
 
-printer.6:	 scanner.6 ast.6
+printer.6:	 scanner.6 ast.6 tabwriter.6
+
 
 %.6:	%.go
 	$(G) $(F) $<

usr/gri/pretty/parser.go

@@ -469,8 +469,14 @@ func (P *Parser) ParseFunctionType() *AST.Type {
 func (P *Parser) ParseMethodSpec(list *AST.List) {
 	P.Trace("MethodDecl");
 	
-	list.Add(P.ParseIdent());
+	list.Add(P.ParseIdentList());
-	list.Add(AST.NewTypeExpr(P.ParseFunctionType()));
+	t := AST.BadType;
+	if P.sixg {
+		t = P.ParseType();
+	} else {
+		t = P.ParseFunctionType();
+	}
+	list.Add(AST.NewTypeExpr(t));
 	
 	P.Ecart();
 }
@@ -1485,7 +1491,8 @@ func (P *Parser) ParseDeclaration() *AST.Decl {
 	
 	d := AST.BadDecl;
 	exported := false;
-	if P.tok == Scanner.EXPORT {
+	// TODO don't use bool flag for export
+	if P.tok == Scanner.EXPORT || P.tok == Scanner.PACKAGE {
 		if P.scope_lev == 0 {
 			exported = true;
 		} else {

usr/gri/pretty/printer.go

@@ -9,6 +9,9 @@ import Scanner "scanner"
 import AST "ast"
 import Flag "flag"
 import Fmt "fmt"
+import IO "io"
+import OS "os"
+import TabWriter "tabwriter"
 
 var tabwith = Flag.Int("tabwidth", 4, nil, "tab width");
 var comments = Flag.Bool("comments", false, nil, "enable printing of comments");
@@ -24,180 +27,11 @@ func assert(p bool) {
 }
 
 
-func PrintBlanks(n int) {
-	// TODO make this faster
-	for ; n > 0; n-- {
-		print(" ");
-	}
-}
-
-
-// ----------------------------------------------------------------------------
-// Implemententation of flexible tab stops.
-
-// Buffer is a representation for a list of lines consisting of
-// cells. A new cell is added for each Tab() call, and a new line
-// is added for each Newline() call.
-//
-// The lines are formatted and printed such that all cells in a column
-// of adjacent cells have the same width (by adding padding). For more
-// details see: http://nickgravgaard.com/elastictabstops/index.html .
-
-type Buffer struct {
-	cell string;  // current cell (last cell in last line, not in lines yet)
-	lines AST.List;  // list of lines; each line is a list of cells (strings)
-	widths AST.List;  // list of column widths - (re-)used during formatting
-}
-
-
-// Implementation
-// (Do not use these functions outside the Buffer implementation).
-
-func (b *Buffer) AddLine() {
-	b.lines.Add(AST.NewList());
-}
-
-
-func (b *Buffer) Line(i int) *AST.List {
-	return b.lines.at(i).(*AST.List);
-}
-
-
-func (b *Buffer) LastLine() *AST.List {
-	return b.lines.last().(*AST.List);
-}
-
-
-// debugging support
-func (b *Buffer) Dump() {
-	for i := 0; i < b.lines.len(); i++ {
-		line := b.Line(i);
-		print("(", i, ") ");
-		for j := 0; j < line.len(); j++ {
-			print("[", line.at(j).(string), "]");
-		}
-		print("\n");
-	}
-	print("\n");
-}
-
-
-func (b *Buffer) PrintLines(line0, line1 int) {
-	for i := line0; i < line1; i++ {
-		line := b.Line(i);
-		for j := 0; j < line.len(); j++ {
-			s := line.at(j).(string);
-			print(s);
-			if j < b.widths.len() {
-				nsep := b.widths.at(j).(int) - len(s);
-				assert(nsep >= 0);
-				PrintBlanks(nsep);
-			} else {
-				assert(j == b.widths.len());
-			}
-		}
-		println();
-	}
-}
-
-
-func (b *Buffer) Format(line0, line1 int) {
-	column := b.widths.len();
-	
-	last := line0;
-	for this := line0; this < line1; this++ {
-		line := b.Line(this);
-		
-		if column < line.len() - 1 {
-			// cell exists in this column
-			// (note that the last cell per line is ignored)
-			
-			// print unprinted lines until beginning of block
-			b.PrintLines(last, this);
-			last = this;
-			
-			// column block begin
-			width := int(tabwith.IVal());  // minimal width
-			for ; this < line1; this++ {
-				line := b.Line(this);
-				if column < line.len() - 1 {
-					// cell exists in this column
-					// update width
-					w := len(line.at(column).(string)) + 1; // 1 = minimum space between cells
-					if w > width {
-						width = w;
-					}
-				} else {
-					break
-				}
-			}
-			// column block end
-
-			// format and print all columns to the right of this column
-			// (we know the widths of this column and all columns to the left)
-			b.widths.Add(width);
-			b.Format(last, this);
-			b.widths.Pop();
-			last = this;
-		}
-	}
-
-	// print unprinted lines until end
-	b.PrintLines(last, line1);
-}
-
-
-// Buffer interface
-// (Use these functions to interact with Buffers).
-
-func (b *Buffer) Init() {
-	b.lines.Init();
-	b.widths.Init();
-	b.AddLine();  // the very first line
-}
-
-
-func (b *Buffer) EmptyLine() bool {
-	return b.LastLine().len() == 0 && len(b.cell) == 0;
-}
-
-
-func (b *Buffer) Tab() {
-	b.LastLine().Add(b.cell);
-	b.cell = "";
-}
-
-
-func (b *Buffer) Newline() {
-	b.Tab();  // add last cell to current line
-	
-	if b.LastLine().len() == 1 {
-		// The current line has only one cell which does not have an impact
-		// on the formatting of the following lines (the last cell per line
-		// is ignored by Format), thus we can print the buffer contents.
-		assert(b.widths.len() == 0);
-		b.Format(0, b.lines.len());
-		assert(b.widths.len() == 0);
-		
-		// reset the buffer
-		b.lines.Clear();
-	}
-	
-	b.AddLine();
-	assert(len(b.cell) == 0);
-}
-
-
-func (b *Buffer) Print(s string) {
-	b.cell += s;
-}
-
-
 // ----------------------------------------------------------------------------
 // Printer
 
 export type Printer struct {
-	buf Buffer;
+	writer IO.Write;
 	
 	// formatting control
 	lastpos int;  // pos after last string
@@ -213,13 +47,18 @@ export type Printer struct {
 }
 
 
+func (P *Printer) Printf(fmt string, s ...) {
+	Fmt.fprintf(P.writer, fmt, s);
+}
+
+
 func (P *Printer) String(pos int, s string) {
 	if pos == 0 {
 		pos = P.lastpos;  // estimate
 	}
 
 	if P.semi && P.level > 0 {  // no semicolons at level 0
-		P.buf.Print(";");
+		P.Printf(";");
 	}
 
 	//print("--", pos, "[", s, "]\n");
@@ -238,26 +77,25 @@ func (P *Printer) String(pos int, s string) {
 		case Scanner.COMMENT_BB:
 			// black space before and after comment on the same line
 			// - print surrounded by blanks
-			P.buf.Print(" ");
+			P.Printf(" %s ", text);
-			P.buf.Print(text);
-			P.buf.Print(" ");
 
 		case Scanner.COMMENT_BW:
 			// only white space after comment on the same line
 			// - put into next cell
-			P.buf.Tab();
+			P.Printf("\t%s", text);
-			P.buf.Print(text);
 			
 		case Scanner.COMMENT_WW, Scanner.COMMENT_WB:
 			// only white space before comment on the same line
 			// - indent
+			/*
 			if !P.buf.EmptyLine() {
 				P.buf.Newline();
 			}
+			*/
 			for i := P.indent; i > 0; i-- {
-				P.buf.Tab();
+				P.Printf("\t");
 			}
-			P.buf.Print(text);
+			P.Printf("%s", text);
 
 		default:
 			panic("UNREACHABLE");
@@ -266,9 +104,9 @@ func (P *Printer) String(pos int, s string) {
 		if text[1] == '/' {
 			// line comments must end in newline
 			// TODO should we set P.newl instead?
-			P.buf.Newline();
+			P.Printf("\n");
 			for i := P.indent; i > 0; i-- {
-				P.buf.Tab();
+				P.Printf("\t");
 			}
 			at_line_begin = true;
 		}
@@ -286,19 +124,18 @@ func (P *Printer) String(pos int, s string) {
 	}
 	
 	if P.newl > 0 {
-		P.buf.Newline();
+		P.Printf("\n");
 		if P.newl > 1 {
 			for i := P.newl; i > 1; i-- {
-				//P.buf.Flush();
+				P.Printf("\n");
-				P.buf.Newline();
 			}
 		}
 		for i := P.indent; i > 0; i-- {
-			P.buf.Tab();
+			P.Printf("\t");
 		}
 	}
 
-	P.buf.Print(s);
+	P.Printf("%s", s);
 
 	P.lastpos = pos + len(s);
 	P.semi, P.newl = false, 0;
@@ -311,8 +148,7 @@ func (P *Printer) Blank() {
 
 
 func (P *Printer) Tab() {
-	P.String(0, "");
+	P.String(0, "\t");
-	P.buf.Tab();
 }
 
 
@@ -712,7 +548,9 @@ func (P *Printer) Declaration(d *AST.Decl, parenthesized bool) {
 		P.Expr(d.ident);
 		
 		if d.typ != nil {
-			P.Blank();
+			if d.tok != Scanner.FUNC {
+				P.Blank();
+			}
 			P.Type(d.typ);
 		}
 
@@ -756,7 +594,7 @@ func (P *Printer) Declaration(d *AST.Decl, parenthesized bool) {
 
 func (P *Printer) Program(p *AST.Program) {
 	// TODO should initialize all fields?
-	P.buf.Init();
+	P.writer = TabWriter.MakeTabWriter(OS.Stdout, 4);
 	
 	P.clist = p.comments;
 	P.cindex = 0;

usr/gri/pretty/selftest2.go

@@ -22,14 +22,14 @@ var (
 
 
 func main() {
-// the prolog
+// the prologue
 	for i := 0; i <= 10 /* limit */; i++ {
 		println(i);  // the index
 		println(i + 1);  // the index + 1
 		println(i + 1000);  // the index + 1000
 		println();
 	}
-// the epilog
+// the epilogue
 	println("foo");  // foo
 	println("foobar");  // foobar
 var x int;

usr/gri/pretty/tabwriter.go

@@ -0,0 +1,285 @@
+// Copyright 2009 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.
+
+package tabwriter
+
+import (
+	OS "os";
+	IO "io";
+	Vector "vector";
+)
+
+
+// ----------------------------------------------------------------------------
+// ByteArray
+
+type ByteArray struct {
+	a *[]byte;
+}
+
+
+func (b *ByteArray) Init(initial_size int) {
+	b.a = new([]byte, initial_size)[0 : 0];
+}
+
+
+func (b *ByteArray) Clear() {
+	b.a = b.a[0 : 0];
+}
+
+
+func (b *ByteArray) Len() int {
+	return len(b.a);
+}
+
+
+func (b *ByteArray) At(i int) byte {
+	return b.a[i];
+}
+
+
+func (b *ByteArray) Set(i int, x byte) {
+	b.a[i] = x;
+}
+
+
+func (b *ByteArray) Slice(i, j int) *[]byte {
+	return b.a[i : j];  // BUG should really be &b.a[i : j]
+}
+
+
+func (b *ByteArray) Append(s *[]byte) {
+	a := b.a;
+	n := len(a);
+	m := n + len(s);
+
+	if m > cap(a) {
+		n2 := 2*n;
+		if m > n2 {
+			n2 = m;
+		}
+		b := new([]byte, n2);
+		for i := 0; i < n; i++ {
+			b[i] = a[i];
+		}
+		a = b;
+	}
+
+	a = a[0 : m];
+	for i := len(s) - 1; i >= 0; i-- {
+		a[n + i] = s[i];
+	}
+	b.a = a;
+}
+
+
+// ----------------------------------------------------------------------------
+// Implemententation of flexible tab stops.
+
+// TabWriter is a representation for a list of lines consisting of
+// cells. A new cell is added for each Tab() call, and a new line
+// is added for each Newline() call.
+//
+// The lines are formatted and printed such that all cells in a column
+// of adjacent cells have the same width (by adding padding). For more
+// details see: http://nickgravgaard.com/elastictabstops/index.html .
+
+type TabWriter struct {
+	// configuration
+	writer IO.Write;
+	tabwidth int;
+
+	// current state
+	buf ByteArray;  // the collected text w/o tabs and newlines
+	width int;  // width of last incomplete cell
+	lines Vector.Vector;  // list of lines; each line is a list of cell widths
+	widths Vector.Vector;  // list of column widths - (re-)used during formatting
+}
+
+
+func (b *TabWriter) AddLine() {
+	b.lines.Append(Vector.New());
+}
+
+
+func (b *TabWriter) Init(writer IO.Write, tabwidth int) {
+	b.writer = writer;
+	b.tabwidth = tabwidth;
+	
+	b.buf.Init(1024);
+	b.lines.Init();
+	b.widths.Init();
+	b.AddLine();  // the very first line
+}
+
+
+func (b *TabWriter) Line(i int) *Vector.Vector {
+	return b.lines.At(i).(*Vector.Vector);
+}
+
+
+func (b *TabWriter) LastLine() *Vector.Vector {
+	return b.lines.At(b.lines.Len() - 1).(*Vector.Vector);
+}
+
+
+// debugging support
+func (b *TabWriter) Dump() {
+	pos := 0;
+	for i := 0; i < b.lines.Len(); i++ {
+		line := b.Line(i);
+		print("(", i, ") ");
+		for j := 0; j < line.Len(); j++ {
+			w := line.At(j).(int);
+			print("[", string(b.buf.a[pos : pos + w]), "]");
+			pos += w;
+		}
+		print("\n");
+	}
+	print("\n");
+}
+
+
+var Blanks = &[]byte{' ', ' ', ' ', ' ', ' ', ' ', ' ', ' '}
+var Newline = &[]byte{'\n'}
+
+func (b *TabWriter) WriteBlanks(n int) {
+	for n >= len(Blanks) {
+		m, err := b.writer.Write(Blanks);
+		n -= len(Blanks);
+	}
+	m, err := b.writer.Write(Blanks[0 : n]);
+}
+
+
+func (b *TabWriter) PrintLines(pos int, line0, line1 int) int {
+	for i := line0; i < line1; i++ {
+		line := b.Line(i);
+		for j := 0; j < line.Len(); j++ {
+			w := line.At(j).(int);
+			m, err := b.writer.Write(b.buf.a[pos : pos + w]);
+			if m != w {
+				panic();
+			}
+			pos += w;
+			if j < b.widths.Len() {
+				b.WriteBlanks(b.widths.At(j).(int) - w);
+			}
+		}
+		m, err := b.writer.Write(Newline);
+	}
+	return pos;
+}
+
+
+func (b *TabWriter) Format(pos int, line0, line1 int) int {
+	column := b.widths.Len();
+	
+	last := line0;
+	for this := line0; this < line1; this++ {
+		line := b.Line(this);
+		
+		if column < line.Len() - 1 {
+			// cell exists in this column
+			// (note that the last cell per line is ignored)
+			
+			// print unprinted lines until beginning of block
+			pos = b.PrintLines(pos, last, this);
+			last = this;
+			
+			// column block begin
+			width := b.tabwidth;  // minimal width
+			for ; this < line1; this++ {
+				line = b.Line(this);
+				if column < line.Len() - 1 {
+					// cell exists in this column
+					// update width
+					w := line.At(column).(int) + 1; // 1 = minimum space between cells
+					if w > width {
+						width = w;
+					}
+				} else {
+					break
+				}
+			}
+			// column block end
+
+			// format and print all columns to the right of this column
+			// (we know the widths of this column and all columns to the left)
+			b.widths.Append(width);
+			pos = b.Format(pos, last, this);
+			b.widths.Remove(b.widths.Len() - 1);
+			last = this;
+		}
+	}
+
+	// print unprinted lines until end
+	return b.PrintLines(pos, last, line1);
+}
+
+
+func (b *TabWriter) EmptyLine() bool {
+	return b.LastLine().Len() == 0 && b.width == 0;
+}
+
+
+func (b *TabWriter) Tab() {
+	b.LastLine().Append(b.width);
+	b.width = 0;
+}
+
+
+func (b *TabWriter) Newline() {
+	b.Tab();  // add last cell to current line
+	
+	if b.LastLine().Len() == 1 {
+		// The current line has only one cell which does not have an impact
+		// on the formatting of the following lines (the last cell per line
+		// is ignored by Format), thus we can print the TabWriter contents.
+		if b.widths.Len() != 0 {
+			panic();
+		}
+		//b.Dump();
+		b.Format(0, 0, b.lines.Len());
+		if b.widths.Len() != 0 {
+			panic();
+		}
+		
+		// reset the TabWriter
+		b.width = 0;
+		b.buf.Clear();
+		b.lines.Reset();
+	}
+	
+	b.AddLine();
+}
+
+
+func (b *TabWriter) Write(buf *[]byte) (i int, err *OS.Error) {
+	i0, n := 0, len(buf);
+	for i = 0; i < n; i++ {
+		switch buf[i] {
+		case '\t':
+			b.width += i - i0;
+			b.buf.Append(buf[i0 : i]);
+			i0 = i + 1;  // don't append '\t'
+			b.Tab();
+		case '\n':
+			b.width += i - i0;
+			b.buf.Append(buf[i0 : i]);
+			i0 = i + 1;  // don't append '\n'
+			b.Newline();
+		}
+	}
+	b.width += n - i0;
+	b.buf.Append(buf[i0 : n]);
+	return i, nil;
+}
+
+
+export func MakeTabWriter(writer IO.Write, tabwidth int) IO.Write {
+	b := new(TabWriter);
+	b.Init(writer, tabwidth);
+	return b;
+}