feat: tokenizer

pkg/cli/arguments.go

@@ -0,0 +1,28 @@
+package cli
+
+import (
+	"flag"
+	"fmt"
+	"log/slog"
+	"os"
+)
+
+type CLIOptions struct {
+	Input string
+}
+
+func ParseOptions(args []string) (*CLIOptions, error) {
+	slog.Info("Parsing CLI arguments.", "args", os.Args)
+
+	// Parse flags and arguments.
+	flag.Parse()
+
+	switch flag.NArg() {
+	case 0:
+		return nil, fmt.Errorf("No input given.")
+	case 1:
+		return &CLIOptions{Input: flag.Arg(0)}, nil
+	default:
+		return nil, fmt.Errorf("More than 1 command-line argument.")
+	}
+}

pkg/cli/exit.go

@@ -0,0 +1,15 @@
+package cli
+
+import (
+	"fmt"
+	"os"
+)
+
+func HandleError(err error) {
+	if err == nil {
+		return
+	}
+
+	fmt.Fprintln(os.Stderr, err)
+	os.Exit(1)
+}