From 34533f06eb30308849ca46a920134d30f2a89de5 Mon Sep 17 00:00:00 2001
From: Robert Griesemer <gri@golang.org>
Date: Tue, 18 Nov 2008 19:25:43 -0800
Subject: [PATCH] - support for alignment via tabs instead of blanks - exclude
 a test due to syntax errors

R=r
OCL=19563
CL=19565
---
 usr/gri/pretty/printer.go   |  9 +++++---
 usr/gri/pretty/tabwriter.go | 43 +++++++++++++++++++++++++++++--------
 usr/gri/pretty/test.sh      |  2 +-
 usr/gri/pretty/untab.go     |  3 ++-
 4 files changed, 43 insertions(+), 14 deletions(-)

diff --git a/usr/gri/pretty/printer.go b/usr/gri/pretty/printer.go
index 039199db46..06f72409a6 100644
--- a/usr/gri/pretty/printer.go
+++ b/usr/gri/pretty/printer.go
@@ -13,8 +13,11 @@ 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");
+var (
+	usetabs = Flag.Bool("usetabs", false, nil, "align with tabs instead of blanks");
+	tabwidth = Flag.Int("tabwidth", 4, nil, "tab width");
+	comments = Flag.Bool("comments", false, nil, "enable printing of comments");
+)
 
 
 // ----------------------------------------------------------------------------
@@ -594,7 +597,7 @@ func (P *Printer) Declaration(d *AST.Decl, parenthesized bool) {
 
 func (P *Printer) Program(p *AST.Program) {
 	// TODO should initialize all fields?
-	P.writer = TabWriter.MakeTabWriter(OS.Stdout, 4);
+	P.writer = TabWriter.MakeTabWriter(OS.Stdout, usetabs.BVal(), int(tabwidth.IVal()));
 	
 	P.clist = p.comments;
 	P.cindex = 0;
diff --git a/usr/gri/pretty/tabwriter.go b/usr/gri/pretty/tabwriter.go
index e97eea9c4b..7ba7a0d2bc 100644
--- a/usr/gri/pretty/tabwriter.go
+++ b/usr/gri/pretty/tabwriter.go
@@ -88,6 +88,7 @@ func (b *ByteArray) Append(s *[]byte) {
 export type TabWriter struct {
 	// configuration
 	writer IO.Write;
+	usetabs bool;
 	tabwidth int;
 
 	// current state
@@ -103,8 +104,9 @@ func (b *TabWriter) AddLine() {
 }
 
 
-func (b *TabWriter) Init(writer IO.Write, tabwidth int) {
+func (b *TabWriter) Init(writer IO.Write, usetabs bool, tabwidth int) {
 	b.writer = writer;
+	b.usetabs = usetabs;
 	b.tabwidth = tabwidth;
 	
 	b.buf.Init(1024);
@@ -141,15 +143,33 @@ func (b *TabWriter) Dump() {
 }
 
 
+var Tabs = &[]byte{'\t', '\t', '\t', '\t', '\t', '\t', '\t', '\t'}
 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);
+
+func (b *TabWriter) Padding(textwidth, cellwidth int) {
+	n := cellwidth - textwidth;
+	if n < 0 {
+		panic("internal error");
+	}
+	if b.usetabs {
+		if cellwidth % b.tabwidth != 0 {
+			panic("internal error");  // cellwidth should be a multiple of tabwidth
+		}
+		n = (n + b.tabwidth - 1) / b.tabwidth;
+		for n > len(Tabs) {
+			m, err := b.writer.Write(Tabs);
+			n -= len(Tabs);
+		}
+		m, err := b.writer.Write(Tabs[0 : n]);
+	} else {
+		for n > len(Blanks) {
+			m, err := b.writer.Write(Blanks);
+			n -= len(Blanks);
+		}
+		m, err := b.writer.Write(Blanks[0 : n]);
 	}
-	m, err := b.writer.Write(Blanks[0 : n]);
 }
 
 
@@ -164,7 +184,7 @@ func (b *TabWriter) PrintLines(pos int, line0, line1 int) int {
 			}
 			pos += w;
 			if j < b.widths.Len() {
-				b.WriteBlanks(b.widths.At(j).(int) - w);
+				b.Padding(w, b.widths.At(j).(int));
 			}
 		}
 		m, err := b.writer.Write(Newline);
@@ -205,6 +225,11 @@ func (b *TabWriter) Format(pos int, line0, line1 int) int {
 			}
 			// column block end
 
+			if b.usetabs {
+				// make width a multiple of the tab width
+				width = ((width + b.tabwidth - 1) / b.tabwidth) * b.tabwidth;
+			}
+			
 			// 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);
@@ -277,8 +302,8 @@ func (b *TabWriter) Write(buf *[]byte) (i int, err *OS.Error) {
 }
 
 
-export func MakeTabWriter(writer IO.Write, tabwidth int) *TabWriter {
+export func MakeTabWriter(writer IO.Write, usetabs bool, tabwidth int) *TabWriter {
 	b := new(TabWriter);
-	b.Init(writer, tabwidth);
+	b.Init(writer, usetabs, tabwidth);
 	return b;
 }
diff --git a/usr/gri/pretty/test.sh b/usr/gri/pretty/test.sh
index 2b57aedca7..5492482456 100755
--- a/usr/gri/pretty/test.sh
+++ b/usr/gri/pretty/test.sh
@@ -22,7 +22,7 @@ apply1() {
 	#echo $1 $2
 	case `basename $F` in
 	selftest1.go | func3.go | bug014.go | bug029.go | bug032.go | bug050.go | \
-	bug068.go | bug088.go | bug083.go | bug106.go ) ;;  # skip - files contain syntax errors
+	bug068.go | bug088.go | bug083.go | bug106.go | bug125.go ) ;;  # skip - files contain syntax errors
 	* ) $1 $2; count ;;
 	esac
 }
diff --git a/usr/gri/pretty/untab.go b/usr/gri/pretty/untab.go
index 48f1bcf385..5f033e1b98 100644
--- a/usr/gri/pretty/untab.go
+++ b/usr/gri/pretty/untab.go
@@ -14,6 +14,7 @@ import (
 
 
 var (
+	usetabs = Flag.Bool("usetabs", false, nil, "align with tabs instead of blanks");
 	tabwidth = Flag.Int("tabwidth", 4, nil, "tab width");
 )
 
@@ -35,7 +36,7 @@ func Untab(name string, src *OS.FD, dst *TabWriter.TabWriter) {
 
 func main() {
 	Flag.Parse();
-	dst := TabWriter.MakeTabWriter(OS.Stdout, int(tabwidth.IVal()));
+	dst := TabWriter.MakeTabWriter(OS.Stdout, usetabs.BVal(), int(tabwidth.IVal()));
 	if Flag.NArg() > 0 {
 		for i := 0; i < Flag.NArg(); i++ {
 			name := Flag.Arg(i);
-- 
2.50.0