From 3 Big O to O on parsing and --help

yay.go

@@ -16,33 +16,49 @@ const BuildDir string = "/tmp/yaytmp/"
 // SearchMode is search without numbers.
 const SearchMode int = -1
 
-func operation() (operation string, err error) {
+func usage() {
+	fmt.Println(`usage:  yay <operation> [...]
+    operations:
+    yay {-h --help}
+    yay {-V --version}
+    yay {-D --database} <options> <package(s)>
+    yay {-F --files}    [options] [package(s)]
+    yay {-Q --query}    [options] [package(s)]
+    yay {-R --remove}   [options] <package(s)>
+    yay {-S --sync}     [options] [package(s)]
+    yay {-T --deptest}  [options] [package(s)]
+    yay {-U --upgrade}  [options] <file(s)>
+
+    New operations:
+    yay -Qstats  -  Displays system information
+`)
+}
+
+func parser() (op string, options []string, packages []string, err error) {
 	if len(os.Args) < 2 {
-		return "noop", fmt.Errorf("No operation specified.")
+		err = fmt.Errorf("No operation specified.")
+		return
 	}
+
 	for _, arg := range os.Args[1:] {
 		if arg[0] == '-' && arg[1] != '-' {
-			return arg, nil
+			op = arg
 		}
-	}
-	return "yogurt", nil
-}
 
-func packages() ([]string, error) {
-	var ps []string
-	for _, arg := range os.Args[1:] {
-		if arg[0] != '-' {
-			ps = append(ps, arg)
-		}
-	}
-	return ps, nil
-}
-
-func flags() (fs []string, err error) {
-	for _, arg := range os.Args[1:] {
 		if arg[0] == '-' && arg[1] == '-' {
-			fs = append(fs, arg)
+			if arg == "--help" {
+				op = arg
+			}
+			options = append(options, arg)
 		}
+
+		if arg[0] != '-' {
+			packages = append(packages, arg)
+		}
+	}
+
+	if op == "" {
+		op = "yogurt"
 	}
 
 	return
@@ -52,16 +68,12 @@ func main() {
 	var err error
 	conf, err := readConfig(PacmanConf)
 
-	op, err := operation()
+	op, pkgs, options, err := parser()
 	if err != nil {
 		fmt.Println(err)
 		os.Exit(1)
 	}
 
-	pkgs, _ := packages()
-
-	flag, _ := flags()
-
 	switch op {
 	case "-Qstats":
 		err = stats(&conf)
@@ -70,15 +82,17 @@ func main() {
 			err = searchMode(pkg, &conf)
 		}
 	case "-S":
-		err = InstallPackage(pkgs, &conf, flag)
+		err = InstallPackage(pkgs, &conf, options)
 	case "-Syu", "-Suy":
-		err = updateAndInstall(&conf, flag)
+		err = updateAndInstall(&conf, options)
 	case "yogurt":
 		for _, pkg := range pkgs {
-			err = searchAndInstall(pkg, &conf, flag)
+			err = searchAndInstall(pkg, &conf, options)
 		}
+	case "--help", "-h":
+		usage()
 	default:
-		err = passToPacman(op, pkgs, flag)
+		err = passToPacman(op, pkgs, options)
 	}
 
 	if err != nil {