Use re.sub for ireplace - works better then my early attempts

Author: dmptrluke

cloudbot/util/formatting.py

@@ -173,24 +173,12 @@ def ireplace(text, old, new, count=None):
     old replaced by new. If the optional argument count is given, only the first count
     occurrences are replaced.
     """
-    last_idx = 0
-    idx = 0
-    num = 0
-    while idx < len(text):
-        index_l = text.lower().find(old.lower(), idx)
-        if index_l == -1:
-            return text
-
-        text = text[:index_l] + new + text[index_l + len(old):]
-        idx = index_l + len(old)
-        num += 1
-        if count and num >= count:
-            break
-        # if the function is just looping, end it
-        if idx == last_idx:
-            break
-        last_idx = int(idx)
-    return text
+    pattern = re.compile(re.escape(old), re.IGNORECASE)
+
+    if count:
+        return pattern.sub(new, text, count=count)
+    else:
+        return pattern.sub(new, text)
 
 
 def multi_replace(text, word_dic):

cloudbot/util/test/test_formatting.py

@@ -98,6 +98,9 @@ def test_ireplace():
     assert ireplace(test_ireplace_input, "fox", "cat", 1) == "The quick brown cat fox FOX jumped over the lazy dog"
     assert ireplace(test_ireplace_input, "fox", "cat", 2) == "The quick brown cat cat FOX jumped over the lazy dog"
 
+    # test blank input - this should behave like the native string.replace()
+    assert ireplace("Hello", "", "?") == "?H?e?l?l?o?"
+
 
 def test_chunk_str():
     assert chunk_str(test_chunk_str_input, 10) == test_chunk_str_result