feat: check the validity of the passed argument

.gitignore

@@ -0,0 +1 @@
+out

internal/tokenizer.go

@@ -1,4 +1,4 @@
-package tokenizer
+package compiler
 
 type TokenType int
 

main.go

@@ -2,12 +2,34 @@ package main
 
 import (
 	"fmt"
+	"io/fs"
 	"os"
+	"path/filepath"
 	"regexp"
+	// "strings"
 )
 
-func process(Path string) {
-	fmt.Println(Path)
+func process(inputPath string) {
+	// outputPath := strings.Replace(inputPath, ".jack", ".xml", 1)
+	source, err := os.ReadFile(inputPath)
+
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(string(source))
+}
+
+func walker(path string, entry fs.DirEntry, err error) error {
+	if err != nil {
+		return err
+	}
+
+	if match, _ := regexp.MatchString(".+\\.jack$", path); match {
+		process(path)
+	}
+
+	return nil
 }
 
 func main() {
@@ -17,9 +39,25 @@ func main() {
 		panic("You must provide a path for a Jack file or a directory that contains Jack files to compile!")
 	}
 
-	Path := args[1]
+	info, err := os.Stat(args[1])
 
-	if match, _ := regexp.MatchString(".+\\.jack", Path); match {
-		process(Path)
+	if err != nil {
+		panic(err)
 	}
+
+	if info.IsDir() {
+		err := filepath.WalkDir(args[1], walker)
+
+		if err != nil {
+			panic(err)
+		}
+
+		return
+	}
+
+	if match, _ := regexp.MatchString(".+\\.jack$", args[1]); !match {
+		panic("You must provide a path for a Jack file or a directory that contains Jack files to compile!")
+	}
+
+	process(args[1])
 }