First cut at a Go pretty printer:

- code scavenged from Go-in-Go front-end (will merge back)
- using "symbol-table" free parsing to build AST
- no printing yet

R=r
OCL=15504
CL=15504

usr/gri/pretty/Makefile

+# 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.
+
+G=6g
+L=6l
+
+pretty: pretty.6
+	$(L) -o pretty pretty.6
+
+test: all
+	pretty *.go
+	# pretty $(GOROOT)/test/fixedbugs/*.go  # some files legally don't compile
+	pretty $(GOROOT)/test/sieve.go
+	pretty $(GOROOT)/src/pkg/*.go
+	pretty $(GOROOT)/src/lib/flag.go
+	pretty $(GOROOT)/src/lib/fmt.go
+	pretty $(GOROOT)/src/lib/rand.go
+	pretty $(GOROOT)/src/lib/math/*.go
+	pretty $(GOROOT)/src/lib/container/*.go
+	pretty $(GOROOT)/src/syscall/*.go
+	pretty base.go decls.go
+	pretty -token_chan base.go decls.go
+	echo "PASSED"
+
+install: pretty
+	cp pretty $(HOME)/bin/pretty
+
+clean:
+	rm -f pretty *.6  *~
+
+pretty.6:	parser.6 printer.6 platform.6 scanner.6
+
+parser.6:	ast.6 scanner.6 utils.6
+
+scanner.6:	utils.6 platform.6
+
+%.6:	%.go
+	$(G) $(F) $<

usr/gri/pretty/ast.go

+// 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 AST;
+
+
+export type Expr interface {
+       pos() int;
+       print();
+}
+
+
+export type Stat interface {
+       pos() int;
+       print();
+}
+
+
+// ---------------------------------------------------------------------
+// Concrete nodes
+
+export type Ident struct {
+       pos_ int;
+       val_ string;
+}
+
+
+func (p *Ident) pos() int {
+     return p.pos_;
+}
+
+
+func (p *Ident) print() {
+     print("x");  // TODO fix this
+}
+
+
+// TODO: complete this

usr/gri/pretty/platform.go

+// 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 Platform
+
+import Utils "utils"
+
+
+// ----------------------------------------------------------------------------
+// Environment
+
+export var
+	GOARCH,
+	GOOS,
+	GOROOT,
+	USER string;
+
+
+func GetEnv(key string) string {
+	n := len(key);
+	for i := 0; i < sys.envc(); i++ {
+		v := sys.envv(i);
+		if v[0 : n] == key {
+			return v[n + 1 : len(v)];  // +1: trim "="
+		}
+	}
+	return "";
+}
+
+
+func init() {
+	GOARCH = GetEnv("GOARCH");
+	GOOS = GetEnv("GOOS");
+	GOROOT = GetEnv("GOROOT");
+	USER = GetEnv("USER");
+}
+
+
+// ----------------------------------------------------------------------------
+// I/O
+
+export const (
+	MAGIC_obj_file = "@gri-go.7@v0";  // make it clear thar it cannot be a source file
+	src_file_ext = ".go";
+	obj_file_ext = ".7";
+)
+
+
+export func ReadObjectFile(filename string) (data string, ok bool) {
+	data, ok = sys.readfile(filename + obj_file_ext);
+	magic := MAGIC_obj_file;  // TODO remove once len(constant) works
+	if ok && len(data) >= len(magic) && data[0 : len(magic)] == magic {
+		return data, ok;
+	}
+	return "", false;
+}
+
+
+export func ReadSourceFile(name string) (data string, ok bool) {
+	name = Utils.TrimExt(name, src_file_ext) + src_file_ext;
+	data, ok = sys.readfile(name);
+	return data, ok;
+}
+
+
+export func WriteObjectFile(name string, data string) bool {
+	name = Utils.TrimExt(Utils.BaseName(name), src_file_ext) + obj_file_ext;
+	return sys.writefile(name, data);
+}

usr/gri/pretty/pretty.go

+// 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 main
+
+import Flag "flag"
+import Platform "platform"
+import Scanner "scanner"
+import AST "ast"  // should not be needed
+import Parser "parser"
+import Printer "printer"
+
+
+var (
+    verbose = Flag.Bool("v", false, nil, "verbose mode");
+    sixg = Flag.Bool("6g", false, nil, "6g compatibility mode");
+    tokenchan = Flag.Bool("token_chan", false, nil, "use token channel for scanner-parser connection");
+)
+
+
+func main() {
+	Flag.Parse();
+	
+	// process files
+	for i := 0; i < Flag.NArg(); i++ {
+	    src_file := Flag.Arg(i);
+
+	    src, ok := Platform.ReadSourceFile(src_file);
+	    if !ok {
+                print("cannot open ", src_file, "\n");
+                return;
+            }
+
+	    scanner := new(Scanner.Scanner);
+            scanner.Open(src_file, src);
+
+	    var tstream *<-chan *Scanner.Token;
+            if tokenchan.BVal() {
+                tstream = scanner.TokenStream();
+	    }
+
+	    parser := new(Parser.Parser);
+	    parser.Open(verbose.BVal(), scanner, tstream);
+
+	    parser.ParseProgram();
+	}
+}

usr/gri/pretty/printer.go

+// 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 Printer;
+
+
+// TODO Fill in the code to print the AST

usr/gri/pretty/utils.go

+// 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 Utils
+
+
+export func BaseName(s string) string {
+	// TODO this is not correct for non-ASCII strings!
+	i := len(s) - 1;
+	for i >= 0 && s[i] != '/' {
+		if s[i] > 128 {
+			panic("non-ASCII string");
+		}
+		i--;
+	}
+	return s[i + 1 : len(s)];
+}
+
+
+export func Contains(s, sub string, pos int) bool {
+	end := pos + len(sub);
+	return pos >= 0 && end <= len(s) && s[pos : end] == sub;
+}
+
+
+export func TrimExt(s, ext string) string {
+	i := len(s) - len(ext);
+	if i >= 0 && s[i : len(s)] == ext {
+		s = s[0 : i];
+	}
+	return s;
+}
+
+
+export func IntToString(x, base int) string {
+	x0 := x;
+	if x < 0 {
+		x = -x;
+		if x < 0 {
+			panic("smallest int not handled");
+		}
+	} else if x == 0 {
+		return "0";
+	}
+
+	// x > 0
+	hex := "0123456789ABCDEF";
+	var buf [32] byte;
+	i := len(buf);
+	for x > 0 {
+		i--;
+		buf[i] = hex[x % base];
+		x /= base;
+	}
+	
+	if x0 < 0 {
+		i--;
+		buf[i] = '-';
+	}
+	
+	return string(buf)[i : len(buf)];
+}