cmd/go: first piece of tool rearrangement

1) create go-tool dir in make.bash
2) clean up stale binaries in make.bash
3) add 'tool' command to go
4) convert goyacc->yacc as a first test tool
Since goyacc stands alone, it's a safe trial.

R=rsc
CC=golang-dev
http://codereview.appspot.com/5576061

9 files changed, 120 insertions, 16 deletions

diff --git a/src/cmd/Makefile b/src/cmd/Makefile
index ee82b8311..089739d05 100644
--- a/src/cmd/Makefile
+++ b/src/cmd/Makefile
@@ -42,7 +42,7 @@ CLEANDIRS=\
 	gofmt\
 	goinstall\
 	gotest\
-	goyacc\
+	yacc\
 
 install: $(patsubst %,%.install,$(DIRS))
 clean: $(patsubst %,%.clean,$(CLEANDIRS))
diff --git a/src/cmd/go/Makefile b/src/cmd/go/Makefile
index 295a14498..3e19d2e3d 100644
--- a/src/cmd/go/Makefile
+++ b/src/cmd/go/Makefile
@@ -18,6 +18,7 @@ GOFILES=\
 	run.go\
 	test.go\
 	testflag.go\
+	tool.go\
 	version.go\
 	vet.go\
 	vcs.go\
diff --git a/src/cmd/go/main.go b/src/cmd/go/main.go
index ca3b1188a..b69c66d3e 100644
--- a/src/cmd/go/main.go
+++ b/src/cmd/go/main.go
@@ -75,6 +75,7 @@ var commands = []*Command{
 	cmdList,
 	cmdRun,
 	cmdTest,
+	cmdTool,
 	cmdVersion,
 	cmdVet,
 
diff --git a/src/cmd/go/tool.go b/src/cmd/go/tool.go
new file mode 100644
index 000000000..24ed78bda
--- /dev/null
+++ b/src/cmd/go/tool.go
@@ -0,0 +1,100 @@
+// Copyright 2011 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 (
+	"fmt"
+	"go/build"
+	"os"
+	"os/exec"
+	"sort"
+	"strings"
+)
+
+var cmdTool = &Command{
+	Run:       runTool,
+	UsageLine: "tool command [args...]",
+	Short:     "run specified go tool",
+	Long: `
+Tool runs the go tool command identified by the arguments.
+With no arguments it prints the list of known tools.
+
+For more about each tool command, see 'go tool command -h'.
+`,
+}
+
+var (
+	toolGoos       = build.DefaultContext.GOOS
+	toolIsWindows  = toolGoos == "windows"
+	toolBinToolDir = build.Path[0].BinDir() + "/go-tool"
+)
+
+const toolWindowsExtension = ".exe"
+
+func runTool(cmd *Command, args []string) {
+	if len(args) == 0 {
+		listTools()
+		return
+	}
+	tool := args[0]
+	// The tool name must be lower-case letters and numbers.
+	for _, c := range tool {
+		switch {
+		case 'a' <= c && c <= 'z', '0' <= c && c <= '9':
+		default:
+			fmt.Fprintf(os.Stderr, "go tool: bad tool name %q\n", tool)
+			exitStatus = 2
+			return
+		}
+	}
+	toolPath := toolBinToolDir + "/" + tool
+	if toolIsWindows {
+		toolPath += toolWindowsExtension
+	}
+	// Give a nice message if there is no tool with that name.
+	if _, err := os.Stat(toolPath); err != nil {
+		fmt.Fprintf(os.Stderr, "go tool: no such tool %q\n", tool)
+		exitStatus = 3
+		return
+	}
+	toolCmd := &exec.Cmd{
+		Path:   toolPath,
+		Args:   args,
+		Stdout: os.Stdout,
+		Stderr: os.Stderr,
+	}
+	err := toolCmd.Run()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "go tool %s failed: %s\n", tool, err)
+		exitStatus = 1
+		return
+	}
+}
+
+// listTools prints a list of the available tools in the go-tools directory.
+func listTools() {
+	toolDir, err := os.Open(toolBinToolDir)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "go tool: no tool directory: %s\n", err)
+		exitStatus = 2
+		return
+	}
+	names, err := toolDir.Readdirnames(-1)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "go tool: can't read directory: %s\n", err)
+		exitStatus = 2
+		return
+	}
+	sort.StringSlice(names).Sort()
+	for _, name := range names {
+		// Unify presentation by going to lower case.
+		name = strings.ToLower(name)
+		// If it's windows, don't show the .exe suffix.
+		if toolIsWindows && strings.HasSuffix(name, toolWindowsExtension) {
+			name = name[:len(name)-len(toolWindowsExtension)]
+		}
+		fmt.Println(name)
+	}
+}
diff --git a/src/cmd/goyacc/Makefile b/src/cmd/yacc/Makefile
index a616e8534..6ce9d54fb 100644
--- a/src/cmd/goyacc/Makefile
+++ b/src/cmd/yacc/Makefile
@@ -4,14 +4,14 @@
 
 include ../../Make.inc
 
-TARG=goyacc
+TARG=yacc
 GOFILES=\
-	goyacc.go\
+	yacc.go\
 
-include ../../Make.cmd
+include ../../Make.tool
 
-units: goyacc units.y
-	./goyacc -p units_ units.y
+units: yacc units.y
+	./yacc -p units_ units.y
 	$(GC) $(GCFLAGS) $(GCIMPORTS) y.go
 	$(LD) -o units y.$O
 
diff --git a/src/cmd/goyacc/doc.go b/src/cmd/yacc/doc.go
index 5dd6abe69..9874a2ae2 100644
--- a/src/cmd/goyacc/doc.go
+++ b/src/cmd/yacc/doc.go
@@ -4,7 +4,8 @@
 
 /*
 
-Goyacc is a version of yacc for Go.
+Yacc is a version of yacc for Go. It is run with the command
+	go tool yacc args...
 It is written in Go and generates parsers written in Go.
 
 It is largely transliterated from the Inferno version written in Limbo
@@ -13,7 +14,8 @@ written in C and documented at
 
 	http://plan9.bell-labs.com/magic/man2html/1/yacc
 
-Yacc adepts will have no trouble adapting to this form of the tool.
+Adepts of the original yacc will have no trouble adapting to this
+form of the tool.
 
 The file units.y in this directory is a yacc grammar for a version of
 the Unix tool units, also written in Go and largely transliterated
@@ -37,9 +39,9 @@ which holds the yyLexer passed to Parse.
 
 Multiple grammars compiled into a single program should be placed in
 distinct packages.  If that is impossible, the "-p prefix" flag to
-goyacc sets the prefix, by default yy, that begins the names of
+yacc sets the prefix, by default yy, that begins the names of
 symbols, including types, the parser, and the lexer, generated and
-referenced by goyacc's generated code.  Setting it to distinct values
+referenced by yacc's generated code.  Setting it to distinct values
 allows multiple grammars to be placed in a single package.
 
 */
diff --git a/src/cmd/goyacc/units.txt b/src/cmd/yacc/units.txt
index ddb2bc294..ddb2bc294 100644
--- a/src/cmd/goyacc/units.txt
+++ b/src/cmd/yacc/units.txt
diff --git a/src/cmd/goyacc/units.y b/src/cmd/yacc/units.y
index 3833486ad..f10cb7c7d 100644
--- a/src/cmd/goyacc/units.y
+++ b/src/cmd/yacc/units.y
@@ -7,17 +7,17 @@
 // See http://plan9.bell-labs.com/plan9/license.html
 
 // Generate parser with prefix "units_":
-//	goyacc -p "units_"
+//	go tool yacc -p "units_"
 
 %{
 
 // units.y
-// example of a goyacc program
+// example of a Go yacc program
 // usage is
-//	goyacc -p "units_" units.y (produces y.go)
+//	go tool yacc -p "units_" units.y (produces y.go)
 //	6g y.go
 //	6l y.6
-//	./6.out $GOROOT/src/cmd/goyacc/units
+//	./6.out $GOROOT/src/cmd/yacc/units
 //	you have: c
 //	you want: furlongs/fortnight
 //		* 1.8026178e+12
@@ -288,7 +288,7 @@ func main() {
 
 	flag.Parse()
 
-	file = os.Getenv("GOROOT") + "/src/cmd/goyacc/units.txt"
+	file = os.Getenv("GOROOT") + "/src/cmd/yacc/units.txt"
 	if flag.NArg() > 0 {
 		file = flag.Arg(0)
 	}
diff --git a/src/cmd/goyacc/goyacc.go b/src/cmd/yacc/yacc.go
index e1b99bed2..c91a72123 100644
--- a/src/cmd/goyacc/goyacc.go
+++ b/src/cmd/yacc/yacc.go
@@ -2933,7 +2933,7 @@ func chcopy(q string) string {
 }
 
 func usage() {
-	fmt.Fprintf(stderr, "usage: goyacc [-o output] [-v parsetable] input\n")
+	fmt.Fprintf(stderr, "usage: yacc [-o output] [-v parsetable] input\n")
 	exit(1)
 }