Have EvTable width correctly handle asian alphabets as per #2166.

evennia/utils/utils.py

@@ -9,7 +9,7 @@ be of use when designing your own game.
 import os
 import gc
 import sys
-import copy 
+import copy
 import types
 import math
 import re
@@ -20,6 +20,7 @@ import traceback
 import importlib
 import importlib.util
 import importlib.machinery
+from unicodedata import east_asian_width
 from twisted.internet.task import deferLater
 from twisted.internet.defer import returnValue  # noqa - used as import target
 from os.path import join as osjoin
@@ -1819,7 +1820,7 @@ def m_len(target):
     back to normal len for other objects.
 
     Args:
-        target (string): A string with potential MXP components
+        target (str): A string with potential MXP components
             to search.
 
     Returns:
@@ -1834,6 +1835,35 @@ def m_len(target):
     return len(target)
 
 
+def display_len(target):
+    """
+    Calculate the 'visible width' of text. This is not necessarily the same as the
+    number of characters in the case of certain asian characters. This will also
+    strip MXP patterns.
+
+    Args:
+        target (string): A string with potential MXP components
+            to search.
+
+    Return:
+        int: The visible width of the target.
+
+    """
+    # Would create circular import if in module root.
+    from evennia.utils.ansi import ANSI_PARSER
+
+    if inherits_from(target, str):
+        # str or ANSIString
+        target = ANSI_PARSER.strip_mxp(target)
+        target = ANSI_PARSER.parse_ansi(target, strip_ansi=True)
+        extra_wide = ("F", "W")
+        return sum(2 if east_asian_width(char) in extra_wide else 1 for char in target)
+    else:
+        return len(target)
+
+
+
+
 # -------------------------------------------------------------------
 # Search handler function
 # -------------------------------------------------------------------