strconv: use go generate to create isprint.go

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/132230043

src/pkg/strconv/isprint.go

@@ -3,7 +3,7 @@
 // license that can be found in the LICENSE file.
 
 // DO NOT EDIT.  GENERATED BY
-//     go run makeisprint.go >x && mv x isprint.go
+//     go run makeisprint.go -output isprint.go
 
 package strconv
 

src/pkg/strconv/makeisprint.go

@@ -4,15 +4,26 @@
 
 // +build ignore
 
-// makeisprint generates the tables for strconv's compact isPrint.
+//
+// usage:
+//
+// go run makeisprint.go -output isprint.go
+//
+
 package main
 
 import (
+	"bytes"
+	"flag"
 	"fmt"
-	"os"
+	"go/format"
+	"io/ioutil"
+	"log"
 	"unicode"
 )
 
+var filename = flag.String("output", "isprint.go", "output file name")
+
 var (
 	range16  []uint16
 	except16 []uint16
@@ -110,6 +121,8 @@ func to16(x []uint32) []uint16 {
 }
 
 func main() {
+	flag.Parse()
+
 	rang, except := scan(0, 0xFFFF)
 	range16 = to16(rang)
 	except16 = to16(except)
@@ -117,49 +130,58 @@ func main() {
 
 	for i := rune(0); i <= unicode.MaxRune; i++ {
 		if isPrint(i) != unicode.IsPrint(i) {
-			fmt.Fprintf(os.Stderr, "%U: isPrint=%v, want %v\n", i, isPrint(i), unicode.IsPrint(i))
-			return
+			log.Fatalf("%U: isPrint=%v, want %v\n", i, isPrint(i), unicode.IsPrint(i))
 		}
 	}
 
-	fmt.Printf(`// Copyright 2013 The Go Authors. All rights reserved.
+	var buf bytes.Buffer
+
+	fmt.Fprintf(&buf, `// Copyright 2013 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.` + "\n\n")
-	fmt.Printf("// DO NOT EDIT.  GENERATED BY\n")
-	fmt.Printf("//     go run makeisprint.go >x && mv x isprint.go\n\n")
-	fmt.Printf("package strconv\n\n")
+// license that can be found in the LICENSE file.`+"\n\n")
+	fmt.Fprintf(&buf, "// DO NOT EDIT.  GENERATED BY\n")
+	fmt.Fprintf(&buf, "//     go run makeisprint.go -output isprint.go\n\n")
+	fmt.Fprintf(&buf, "package strconv\n\n")
 
-	fmt.Printf("// (%d+%d+%d)*2 + (%d)*4 = %d bytes\n\n",
+	fmt.Fprintf(&buf, "// (%d+%d+%d)*2 + (%d)*4 = %d bytes\n\n",
 		len(range16), len(except16), len(except32),
 		len(range32),
 		(len(range16)+len(except16)+len(except32))*2+
 			(len(range32))*4)
 
-	fmt.Printf("var isPrint16 = []uint16{\n")
+	fmt.Fprintf(&buf, "var isPrint16 = []uint16{\n")
 	for i := 0; i < len(range16); i += 2 {
-		fmt.Printf("\t%#04x, %#04x,\n", range16[i], range16[i+1])
+		fmt.Fprintf(&buf, "\t%#04x, %#04x,\n", range16[i], range16[i+1])
 	}
-	fmt.Printf("}\n\n")
+	fmt.Fprintf(&buf, "}\n\n")
 
-	fmt.Printf("var isNotPrint16 = []uint16{\n")
+	fmt.Fprintf(&buf, "var isNotPrint16 = []uint16{\n")
 	for _, r := range except16 {
-		fmt.Printf("\t%#04x,\n", r)
+		fmt.Fprintf(&buf, "\t%#04x,\n", r)
 	}
-	fmt.Printf("}\n\n")
+	fmt.Fprintf(&buf, "}\n\n")
 
-	fmt.Printf("var isPrint32 = []uint32{\n")
+	fmt.Fprintf(&buf, "var isPrint32 = []uint32{\n")
 	for i := 0; i < len(range32); i += 2 {
-		fmt.Printf("\t%#06x, %#06x,\n", range32[i], range32[i+1])
+		fmt.Fprintf(&buf, "\t%#06x, %#06x,\n", range32[i], range32[i+1])
 	}
-	fmt.Printf("}\n\n")
+	fmt.Fprintf(&buf, "}\n\n")
 
-	fmt.Printf("var isNotPrint32 = []uint16{ // add 0x10000 to each entry\n")
+	fmt.Fprintf(&buf, "var isNotPrint32 = []uint16{ // add 0x10000 to each entry\n")
 	for _, r := range except32 {
 		if r >= 0x20000 {
-			fmt.Fprintf(os.Stderr, "%U too big for isNotPrint32\n", r)
-			return
+			log.Fatalf("%U too big for isNotPrint32\n", r)
 		}
-		fmt.Printf("\t%#04x,\n", r-0x10000)
+		fmt.Fprintf(&buf, "\t%#04x,\n", r-0x10000)
+	}
+	fmt.Fprintf(&buf, "}\n")
+
+	data, err := format.Source(buf.Bytes())
+	if err != nil {
+		log.Fatal(err)
+	}
+	err = ioutil.WriteFile(*filename, data, 0644)
+	if err != nil {
+		log.Fatal(err)
 	}
-	fmt.Printf("}\n")
 }

src/pkg/strconv/quote.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:generate go run makeisprint.go -output isprint.go
+
 package strconv
 
 import (