diff --git a/xplace/x.py b/xplace/x.py
index c33a31e..ad6064a 100644
--- a/xplace/x.py
+++ b/xplace/x.py
@@ -1,5 +1,6 @@
 #!/usr/bin/env python3 
 from lark import Lark, Transformer, ParseError, Tree
+from random import shuffle
 
 parser = Lark(r'''
           DIGIT : /[0-9]/
@@ -12,9 +13,9 @@ parser = Lark(r'''
                 | bracketliteral "-" bracketliteral
        brackets : "[" range+ "]" -> either
 
-           char : /[^\\\[\]\{\}\(\)\|\^~\?!]/
+         ?achar : /[^\\\[\]\{\}\(\)\|\^~\?!¿]/
                 | "\\" /\D/
-                | //
+           char : achar?
 
        numrange : DIGITS
                 | DIGITS "-" DIGITS [ "*" DIGITS ] [ "+" DIGITS ]
@@ -23,6 +24,7 @@ parser = Lark(r'''
    ?concat_func : unit
                 | concat_func "{" DIGITS "}"                      -> concat_repeat
                 | concat_func "?"                                 -> zero_or_one
+                | concat_func "¿"                                 -> random
                 | concat_func "~"                                 -> reverse
                 | concat_func "~" NUMBER                          -> roll
                 | concat_func "~{" NUMBER ["," DIGITS] "}"        -> roll
@@ -44,7 +46,7 @@ parser = Lark(r'''
                 | choice ("|" choice_func)+ -> either
 
         ?parens : "(" choice ")"
-        ''', start='choice', ambiguity='resolve__antiscore_sum')
+        ''', start='choice', priority='invert')
 
 class Expand(Transformer):
     def __init__(self, amp=None):
@@ -74,6 +76,10 @@ class Expand(Transformer):
     def zero_or_one(self, args):
         return self.either([[''], args[0]])
 
+    def random(self, args):
+        shuffle(args[0])
+        return args[0]
+
     def either(self, args):
         result = []
         for x in args: