Load asm from commandline

src/main.rs

@@ -1,5 +1,7 @@
 mod vm;
 
+use std::{env, fs};
+use std::io::{stderr, Write};
 use std::sync::Arc;
 use vm::FootVM;
 
@@ -111,16 +113,25 @@ impl ApplicationHandler for App
     }
 }
 
-const ASM_SRC: &'static str = include_str!("../examples/first.asm");
-
 fn main()
 {
-    let mut vm = FootVM::new();
+    let args: Vec<String> = env::args().collect();
-    vm.load(ASM_SRC, Some(&mut std::io::stderr())).expect("");
+    if args.len() < 2
+    {
+        _ = stderr().write("No filename supplied".as_bytes())
+    }
+    else
+    {
+        let src = fs::read_to_string(&args[1])
+            .expect("Unable to read file");
 
-    let event_loop = EventLoop::new().unwrap();
+        let mut vm = FootVM::new();
-    event_loop.set_control_flow(ControlFlow::Poll);
+        vm.load(src.as_str(), Some(&mut std::io::stderr())).expect("");
 
-    let mut app = App::new(vm);
+        let event_loop = EventLoop::new().unwrap();
-    event_loop.run_app(&mut app).expect("");
+        event_loop.set_control_flow(ControlFlow::Poll);
+
+        let mut app = App::new(vm);
+        event_loop.run_app(&mut app).expect("");
+    }
 }