1 files changed, 36 insertions, 2 deletions
diff --git a/bytecode/src/main.rs b/bytecode/src/main.rs
index 8315d5a..89e205a 100644
--- a/bytecode/src/main.rs
+++ b/bytecode/src/main.rs
@@ -3,8 +3,42 @@ mod data;
 mod encoding;
 mod heap;
 
+use std::fs::File;
+
+fn usage() {
+    println!("Usage: bytecode <file>");
+}
+
 fn main() {
-    let prog = encoding::decode(&mut std::io::stdin().lock()).unwrap();
-    let exit_code = bytecode::eval(&prog).unwrap();
+    let filepath = match std::env::args().nth(1) {
+        Some(x) => x,
+        None => {
+            usage();
+            std::process::exit(255);
+        }
+    };
+    let prog = {
+        let mut file = match File::open(filepath) {
+            Ok(x) => x,
+            Err(err) => {
+                println!("Can't open file for reading: {}", err);
+                std::process::exit(255);
+            }
+        };
+        match encoding::decode(&mut file) {
+            Ok(x) => x,
+            Err(err) => {
+                println!("Invalid bytecode: {}", err);
+                std::process::exit(255);
+            }
+        }
+    };
+    let exit_code = match bytecode::eval(&prog) {
+        Ok(x) => x,
+        Err(err) => {
+            println!("{}", err);
+            std::process::exit(255);
+        }
+    };
     std::process::exit(i32::from(exit_code));
 }