memoize open_script

pier.py

@@ -3,6 +3,7 @@
 from glob import glob
 from io import StringIO
 from contextlib import redirect_stdout, redirect_stderr
+from functools import lru_cache
 
 import http.server
 import socketserver
@@ -49,7 +50,10 @@ def run_script(fn):
         exec(code)
     return sio.getvalue()
 
+@lru_cache()
 def open_script(fn):
+    print("reading", fn)
+    print("_" * 80)
     with open(fn) as f:
         src = f.read()
     code = compile(src, fn, "exec")