Read from stdin

src/main.rs

@@ -12,7 +12,7 @@ mod parser;
 mod ir;
 
 fn main() -> std::io::Result<()> {
-    let mut input_file = File::open("sample-initial.amo")?;
+    let mut input_file = std::io::stdin();
 	let mut input = String::with_capacity(4096);
 	input_file.read_to_string(&mut input)?;