1 files changed, 6 insertions, 2 deletions
diff --git a/Lib/_pyrepl/utils.py b/Lib/_pyrepl/utils.py
index cd1df7c..96e917e 100644
--- a/Lib/_pyrepl/utils.py
+++ b/Lib/_pyrepl/utils.py
@@ -1,10 +1,14 @@
 import re
 import unicodedata
+import functools
 
 ANSI_ESCAPE_SEQUENCE = re.compile(r"\x1b\[[ -@]*[A-~]")
 
 
+@functools.cache
 def str_width(c: str) -> int:
+    if ord(c) < 128:
+        return 1
     w = unicodedata.east_asian_width(c)
     if w in ('N', 'Na', 'H', 'A'):
         return 1
@@ -13,6 +17,6 @@ def str_width(c: str) -> int:
 
 def wlen(s: str) -> int:
     length = sum(str_width(i) for i in s)
-
     # remove lengths of any escape sequences
-    return length - sum(len(i) for i in ANSI_ESCAPE_SEQUENCE.findall(s))
+    sequence = ANSI_ESCAPE_SEQUENCE.findall(s)
+    return length - sum(len(i) for i in sequence)