adding --version

Author: yazgazan

config.go

@@ -18,10 +18,11 @@ type config struct {
 	Files  files          `positional-args:"yes" required:"yes"`
 	Ignore ignorePatterns `long:"ignore" short:"i" description:"paths to ignore (glob)"`
 	output
-	IgnoreExcess  bool `long:"ignore-excess" description:"ignore excess keys and arrey elements"`
-	IgnoreValues  bool `long:"ignore-values" description:"ignore scalar's values (only type is compared)"`
-	OutputReport  bool `long:"report" short:"r" description:"output report format"`
-	UseSliceMyers bool `long:"slice-myers" description:"use myers algorithm for slices"`
+	IgnoreExcess  bool   `long:"ignore-excess" description:"ignore excess keys and arrey elements"`
+	IgnoreValues  bool   `long:"ignore-values" description:"ignore scalar's values (only type is compared)"`
+	OutputReport  bool   `long:"report" short:"r" description:"output report format"`
+	UseSliceMyers bool   `long:"slice-myers" description:"use myers algorithm for slices"`
+	Version       func() `long:"version" short:"v" description:"print release version"`
 }
 
 type output struct {
@@ -32,6 +33,10 @@ type output struct {
 
 func readConfig() config {
 	var c config
+	c.Version = func() {
+		fmt.Fprintf(os.Stderr, "%s\n", Version)
+		os.Exit(0)
+	}
 
 	_, err := flags.Parse(&c)
 	if err != nil {

main.go

@@ -17,6 +17,10 @@ const (
 	statusDiffMismatch   = 6
 )
 
+var (
+	Version = "dev"
+)
+
 func main() {
 	var err error
 	conf := readConfig()