fix: small bugs to make it compile

src/main.c

@@ -32,7 +32,10 @@ static int main_loop(struct lexer_context *ctx, struct args_options *options,
 {
     int return_code = SUCCESS;
     // init parser
-    int parser_init();
+    if (!parser_init())
+    {
+        perror("parser initialization failed.");
+    }
 
     // Retrieve and build first AST
     struct ast *command_ast = get_ast(ctx);