add lexer

src/main.rs

@@ -1,3 +1,24 @@
-fn main() {
-    println!("Hello, world!");
+use std::{fs::File, io::Read};
+
+mod lexer;
+use lexer::Lexer;
+
+fn main() -> std::io::Result<()> {
+    let args = std::env::args().collect::<Vec<String>>();
+
+    let mut source = String::new();
+    File::open(&args[1])?.read_to_string(&mut source)?;
+
+    println!("{:?}", source);
+
+    let mut lexer = Lexer::new(&source);
+
+    loop {
+        match lexer.next() {
+            Some(tok) => print!("{tok:?}, "),
+            None => break
+        }
+    }
+
+    Ok(())
 }