uncomment.go

package main

import (
	"flag"
	"fmt"
	"go/parser"
	"go/printer"
	"go/token"
	"log"
	"os"
	"path/filepath"
	"strings"
)

var (
	inFlag  = flag.String("in", "", "input directory")
	outFlag = flag.String("out", "", "output directory")
	inDir   string
	outDir  string
)

func main() {
	flag.Parse()
	if *inFlag == "" {
		fmt.Println("must set -in")
		return
	}
	if *outFlag == "" {
		fmt.Println("must set -out")
		return
	}
	inDir = filepath.Clean(*inFlag)
	outDir = filepath.Clean(*outFlag)
	err := filepath.Walk(inDir, walk)
	if err != nil {
		fmt.Println(err)
		return
	}
}

func replace(path string) string {
	if strings.HasPrefix(path, inDir) {
		path = filepath.Join(outDir, path[len(inDir):])
	}
	return path
}

func walk(in string, info os.FileInfo, err error) error {
	if err != nil {
		panic(err)
	}
	out := replace(in)
	if in == out {
		log.Fatalf("failed to determine output file for %v", in)
	}
	if info.IsDir() {
		log.Printf("creating directory %v", out)
		return os.Mkdir(out, 0744)
	}
	if !strings.HasSuffix(in, ".go") {
		log.Printf("ignoring file %v", in)
		return nil
	}
	fset := token.NewFileSet()
	astFi, err := parser.ParseFile(fset, in, nil, 0) // don't parse comments
	if err != nil {
		log.Fatalf("parse source file %v: %v", in, err)
	}
	outFi, err := os.Create(out)
	if err != nil {
		log.Fatalf("create output file %v: %v", out, err)
	}
	err = printer.Fprint(outFi, fset, astFi)
	if err != nil {
		log.Fatalf("failed to write output file %v: %v", out, err)
	}
	log.Printf("rewrote %v to %v", in, out)
	return nil
}