refactor: reworked cli parsing

it is now easier to add a new cli flag. The new implementation automatically adds any flag of the cli.Flag structure which was added to the cli.OPTIONS array to the flag parsing logic. It also supports displaying all added options with their name and description to the help page which can be viewed by running fleck without any arguments.

cli/cli.go

@@ -5,26 +5,56 @@ import (
 	"fmt"
 )
 
+type Flag struct {
+	Name        string
+	Default     bool
+	Description string
+}
+
 type Arguments struct {
-	ShellMacroEnabled bool
-	InputFile         string
+	flags     map[string]*bool
+	InputFile string
+}
+
+var OPTIONS []Flag = []Flag{
+	{
+		"shell-macro-enabled",
+		false,
+		"enables the dangerous '@shell{command}' macro, which allows the preprocessor to run any command on your system",
+	},
 }
 
 func ParseCli() Arguments {
-	shellMacroEnabled := flag.Bool("shell-macro-enabled", false, "enables the @shell{command} macro")
+	resMap := make(map[string]*bool)
+	for _, f := range OPTIONS {
+		resMap[f.Name] = flag.Bool(f.Name, f.Default, f.Description)
+	}
 
 	flag.Parse()
 	inputFile := flag.Arg(0)
 
 	return Arguments{
-		InputFile:         inputFile,
-		ShellMacroEnabled: *shellMacroEnabled,
+		InputFile: inputFile,
+		flags:     resMap,
 	}
 }
 
 func PrintShortHelp() {
 	fmt.Println(`
 Usage:
     fleck [OPTIONS] file
-    `)
+
+Options:`)
+	for _, v := range OPTIONS {
+		fmt.Printf("\t--%s: %s\n", v.Name, v.Description)
+	}
+	fmt.Println("")
+}
+
+func GetFlag(a Arguments, name string) bool {
+	v, ok := a.flags[name]
+	if !ok {
+		return false
+	}
+	return *v
 }

fleck.go

@@ -19,7 +19,7 @@ func main() {
 		os.Exit(1)
 	}
 
-	if ARGUMENTS.ShellMacroEnabled {
+	if cli.GetFlag(ARGUMENTS, "shell-macro-enabled") {
 		log.Println("warning: 'shell-macro-enabled' flag specified, this can harm your operating system and make it vulnerable for attack, proceed at your own digression")
 	}