feat: args handling

example/hello_world.vy

@@ -0,0 +1 @@
+(print '(Hello, World!))

src/main.rs

@@ -1,13 +1,45 @@
+use std::{process::exit, fs::read_to_string};
+
 pub mod parser;
 
-fn main() {
-    let src = r#"
-    (print "Hello, World!")
-    (print '(hello, world!))
-    "#;
+const EXECUTABLE_NAME: &str = env!("CARGO_PKG_NAME");
 
-    let parsed = parser::parse(src);
-    for result in parsed {
-        println!("{:?}", result);
+fn main() {
+    let args = std::env::args().collect::<Vec<String>>();
+    let mut args_index: usize = 0;
+    match args.len() {
+        // No argument provided
+        1 => { display_help(1); },
+        _ => {
+            while args.len() > args_index {
+                let arg: &str = &args[args_index];
+                match arg {
+                    "-h" | "--help" => { display_help(0); },
+                    "-v" | "--version" => {
+                        println!("{} version {}", EXECUTABLE_NAME, env!("CARGO_PKG_VERSION"));
+                        exit(0);
+                    },
+                    "-c" | "--compile" => {
+                        args_index += 1;
+                        if args_index < args.len() {
+                            let file_path: &str = &args[args_index];
+                            let file_content: String = read_to_string(file_path).unwrap();
+                            let ast = parser::parse(&file_content);
+                            for node in ast {
+                                println!("{:?}", node);
+                            }
+                        } else {
+                            display_help(1);
+                        }
+                    }
+                    _ => { args_index += 1; }
+                }
+            }
+        }
     }
 }
+
+fn display_help(exit_code: i32) {
+    println!("Usage: {} <file>", EXECUTABLE_NAME);
+    exit(exit_code);
+}