cmd/guru: clean ups to command-line interface

-pos is now a positional argument; -scope is now a flag.
Tidy up usage message.
Update Vim and Emacs scripts and test
Remove call to GOMAXPROCS.
Use log.{SetPrefix,SetFlags} and Fatalf

Change-Id: I3786ed83aecb17d622b29d2a538a374f813f0adc
Reviewed-on: https://go-review.googlesource.com/19438
Reviewed-by: Michael Matloob <matloob@golang.org>

cmd/guru/emacs-test.bash

@@ -26,15 +26,14 @@ mv -f $GOPATH/bin/guru $GOROOT/bin/
 $GOROOT/bin/guru >$log 2>&1 || true # (prints usage and exits 1)
 grep -q "Run.*help" $log || die "$GOROOT/bin/guru not installed"
 
-
 # Run Emacs, set the scope to the guru tool itself,
 # load ./main.go, and describe the "fmt" import.
 emacs --batch --no-splash --no-window-system --no-init \
-    --load $GOROOT/misc/emacs/go-mode.el \
+    --load $GOPATH/src/github.com/dominikh/go-mode.el/go-mode.el \
     --load $thisdir/guru.el \
     --eval '
 (progn
-  (setq go-guru-scope "golang.org/x/tools/cmd/guru")
+  (princ (emacs-version)) ; requires Emacs v23
   (find-file "'$thisdir'/main.go")
   (search-forward "\"fmt\"")
   (backward-char)

cmd/guru/guru.el

@@ -2,20 +2,16 @@
 ;;; Integration of the Go 'guru' analysis tool into Emacs.
 ;;;
 ;;; To install the Go guru, run:
-;;; % export GOROOT=... GOPATH=...
+;;; $ go get golang.org/x/tools/cmd/guru
-;;; % go get golang.org/x/tools/cmd/guru
-;;; % mv $GOPATH/bin/guru $GOROOT/bin/
 ;;;
 ;;; Load this file into Emacs and set go-guru-scope to your
 ;;; configuration. Then, find a file of Go source code, enable
 ;;; go-guru-mode, select an expression of interest, and press `C-c C-o d'
 ;;; (for "describe") or run one of the other go-guru-xxx commands.
-;;;
-;;; TODO(adonovan): simplify installation and configuration by making
-;;; guru a subcommand of 'go tool'.
 
 (require 'compile)
 (require 'go-mode)
+(require 'simple)
 (require 'cl)
 
 (defgroup go-guru nil
@@ -99,12 +95,12 @@ file name with a small hyperlink.  Display the result."
        (string-equal "" go-guru-scope)
        (go-guru-set-scope))
   (let* ((filename (file-truename buffer-file-name))
-         (posflag (if (use-region-p)
+         (posn (if (use-region-p)
-                      (format "-pos=%s:#%d,#%d"
+		   (format "%s:#%d,#%d"
 			   filename
 			   (1- (go--position-bytes (region-beginning)))
 			   (1- (go--position-bytes (region-end))))
-                    (format "-pos=%s:#%d"
+		 (format "%s:#%d"
 			 filename
 			 (1- (position-bytes (point))))))
          (env-vars (go-root-and-paths))
@@ -114,8 +110,8 @@ file name with a small hyperlink.  Display the result."
       (setq buffer-read-only nil)
       (erase-buffer)
       (insert "Go Guru\n")
-      (let ((args (append (list go-guru-command nil t nil posflag mode)
+      (let ((args (list go-guru-command nil t nil
-                          (split-string go-guru-scope " " t))))
+			"-scope" go-guru-scope mode posn)))
         ;; Log the command to *Messages*, for debugging.
         (message "Command: %s:" args)
         (message nil) ; clears/shrinks minibuffer

cmd/guru/guru.vim

@@ -68,14 +68,14 @@ func! s:RunGuru(mode, selected) range abort
   if a:selected != -1
     let pos1 = s:getpos(line("'<"), col("'<"))
     let pos2 = s:getpos(line("'>"), col("'>"))
-    let cmd = printf('%s -pos=%s:#%d,#%d %s %s',
+    let cmd = printf('%s -scope=\'%s\' %s %s:#%d,#%d',
       \  s:go_guru,
-      \  shellescape(fname), pos1, pos2, a:mode, shellescape(sname))
+      \  shellescape(fname), shellescape(sname), a:mode, pos1, pos2)
   else
     let pos = s:getpos(line('.'), col('.'))
-    let cmd = printf('%s -pos=%s:#%d %s %s',
+    let cmd = printf('%s -scope=\'%s\' %s %s:#%d',
       \  s:go_guru,
-      \  shellescape(fname), pos, a:mode, shellescape(sname))
+      \  shellescape(fname), shellescape(sname), a:mode, pos)
   endif
   call s:qflist(system(cmd))
 endfun

cmd/guru/main.go

@@ -21,23 +21,20 @@ import (
 	"io"
 	"log"
 	"os"
-	"runtime"
 	"runtime/pprof"
+	"strings"
 
 	"golang.org/x/tools/go/buildutil"
-	"golang.org/x/tools/go/loader"
 )
 
-var posFlag = flag.String("pos", "",
+// flags
-	"Filename and byte offset or extent of a syntax element about which to query, "+
+var (
-		"e.g. foo.go:#123,#456, bar.go:#123.")
+	scopeFlag      = flag.String("scope", "", "comma-separated list of `packages` to which the analysis should be limited (default=all)")
-
+	ptalogFlag     = flag.String("ptalog", "", "write points-to analysis log to `file`")
-var ptalogFlag = flag.String("ptalog", "",
+	formatFlag     = flag.String("format", "plain", "output `format`; one of {plain,json,xml}")
-	"Location of the points-to analysis log file, or empty to disable logging.")
+	reflectFlag    = flag.Bool("reflect", false, "analyze reflection soundly (slow)")
-
+	cpuprofileFlag = flag.String("cpuprofile", "", "write CPU profile to `file`")
-var formatFlag = flag.String("format", "plain", "Output format.  One of {plain,json,xml}.")
+)
-
-var reflectFlag = flag.Bool("reflect", false, "Analyze reflection soundly (slow).")
 
 func init() {
 	flag.Var((*buildutil.TagsFlag)(&build.Default.BuildTags), "tags", buildutil.TagsFlagDoc)
@@ -46,15 +43,7 @@ func init() {
 const useHelp = "Run 'guru -help' for more information.\n"
 
 const helpMessage = `Go source code guru.
-Usage: guru [<flag> ...] <mode> <args> ...
+Usage: guru [flags] <mode> <position>
-
-The -format flag controls the output format:
-	plain	an editor-friendly format in which every line of output
-		is of the form "pos: text", where pos is "-" if unknown.
-	json	structured data in JSON syntax.
-	xml	structured data in XML syntax.
-
-The -pos flag is required in all modes.
 
 The mode argument determines the query to perform:
 
@@ -71,29 +60,24 @@ The mode argument determines the query to perform:
 	what		show basic information about the selected syntax node
 	whicherrs	show possible values of the selected error variable
 
-The user manual is available here:  http://golang.org/s/guru-user-manual
+The position argument specifies the filename and byte offset (or range)
+of the syntax element to query.  For example:
 
-Examples:
+	foo.go:#123,#128
+	bar.go:#123
 
-Describe the syntax at offset 530 in this file (an import spec):
+The -format flag controls the output format:
-% guru -pos=src/golang.org/x/tools/cmd/guru/main.go:#530 describe \
+	plain	an editor-friendly format in which every line of output
-   golang.org/x/tools/cmd/guru
+		is of the form "pos: text", where pos is "-" if unknown.
+	json	structured data in JSON syntax.
+	xml	structured data in XML syntax.
 
-` + loader.FromArgsUsage
+User manual: http://golang.org/s/oracle-user-manual
 
-var cpuprofile = flag.String("cpuprofile", "", "write cpu profile to file")
+Example: describe syntax at offset 530 in this file (an import spec):
 
-func init() {
+  $ guru describe src/golang.org/x/tools/cmd/guru/main.go:#530 
-	// If $GOMAXPROCS isn't set, use the full capacity of the machine.
+`
-	// For small machines, use at least 4 threads.
-	if os.Getenv("GOMAXPROCS") == "" {
-		n := runtime.NumCPU()
-		if n < 4 {
-			n = 4
-		}
-		runtime.GOMAXPROCS(n)
-	}
-}
 
 func printHelp() {
 	fmt.Fprintln(os.Stderr, helpMessage)
@@ -102,6 +86,9 @@ func printHelp() {
 }
 
 func main() {
+	log.SetPrefix("guru: ")
+	log.SetFlags(0)
+
 	// Don't print full help unless -help was requested.
 	// Just gently remind users that it's there.
 	flag.Usage = func() { fmt.Fprint(os.Stderr, useHelp) }
@@ -115,13 +102,12 @@ func main() {
 	}
 
 	args := flag.Args()
-	if len(args) == 0 || args[0] == "" {
+	if len(args) != 2 {
-		fmt.Fprint(os.Stderr, "guru: a mode argument is required.\n"+useHelp)
+		flag.Usage()
 		os.Exit(2)
 	}
+	mode, posn := args[0], args[1]
 
-	mode := args[0]
-	args = args[1:]
 	if mode == "help" {
 		printHelp()
 		os.Exit(2)
@@ -147,8 +133,8 @@ func main() {
 	}
 
 	// Profiling support.
-	if *cpuprofile != "" {
+	if *cpuprofileFlag != "" {
-		f, err := os.Create(*cpuprofile)
+		f, err := os.Create(*cpuprofileFlag)
 		if err != nil {
 			log.Fatal(err)
 		}
@@ -161,23 +147,21 @@ func main() {
 	case "json", "plain", "xml":
 		// ok
 	default:
-		fmt.Fprintf(os.Stderr, "guru: illegal -format value: %q.\n"+useHelp, *formatFlag)
+		log.Fatalf("illegal -format value: %q.\n"+useHelp, *formatFlag)
-		os.Exit(2)
 	}
 
 	// Ask the guru.
 	query := Query{
 		Mode:       mode,
-		Pos:        *posFlag,
+		Pos:        posn,
 		Build:      &build.Default,
-		Scope:      args,
+		Scope:      strings.Split(*scopeFlag, ","),
 		PTALog:     ptalog,
 		Reflection: *reflectFlag,
 	}
 
 	if err := Run(&query); err != nil {
-		fmt.Fprintf(os.Stderr, "guru: %s\n", err)
+		log.Fatal(err)
-		os.Exit(1)
 	}
 
 	// Print the result.
@@ -185,16 +169,14 @@ func main() {
 	case "json":
 		b, err := json.MarshalIndent(query.Serial(), "", "\t")
 		if err != nil {
-			fmt.Fprintf(os.Stderr, "guru: JSON error: %s\n", err)
+			log.Fatalf("JSON error: %s", err)
-			os.Exit(1)
 		}
 		os.Stdout.Write(b)
 
 	case "xml":
 		b, err := xml.MarshalIndent(query.Serial(), "", "\t")
 		if err != nil {
-			fmt.Fprintf(os.Stderr, "guru: XML error: %s\n", err)
+			log.Fatalf("XML error: %s", err)
-			os.Exit(1)
 		}
 		os.Stdout.Write(b)