Restricted the characters that a prefix character can be.

scripts/supybot-wizard

@@ -439,7 +439,12 @@ def main():
         import callbacks
         conf.prefixChars = anything('What would you like your bot\'s '
                                     'prefix character(s) to be?')
-        while callbacks.canonicalName(conf.prefixChars) != conf.prefixChars:
+        invalidPrefixChar = True
+        while invalidPrefixChar:
+            for c in conf.prefixChars:
+                if c not in conf.validPrefixChars:
+                    invalidPrefixChar = True
+                    myPrint('%r is not a valid prefixChar.' % c)
             conf.prefixChars = anything('That includes one or more invalid '
                                         'prefix characters.  What would you'
                                         'like your bot\'s prefix character(s)'

src/Admin.py

@@ -244,8 +244,10 @@ class Admin(privmsgs.CapabilityCheckingPrivmsg):
         Sets the prefix chars by which the bot can be addressed.
         """
         s = privmsgs.getArgs(args)
-        if s.translate(string.ascii, string.ascii_letters) == '':
-            irc.error(msg, 'Prefixes cannot contain letters.')
+        for c in s:
+            if c not in conf.validPrefixChars:
+                s = 'PrefixChars must be something in %r'%conf.validPrefixChars
+                irc.error(msg, s)
         else:
             conf.prefixChars = s
             irc.reply(msg, conf.replySuccess)

src/conf.py

@@ -222,6 +222,12 @@ ignores = []
 ###
 prefixChars = '@'
 
+###
+# validPrefixChars: A string of chars that are allowed to be used as
+#                   prefixChars.
+###
+validPrefixChars = '`~!@#$%^&*()_-+=[{}]\\|\'";:,<.>/?'
+
 ###
 # detailedTracebacks: A boolean describing whether or not the bot will give
 #                     *extremely* detailed tracebacks.  Be cautioned, this eats