src/Pure/Pure.thy

 The Pure theory, with definitions of Isar commands and some lemmas.
 *)
 
 theory Pure
 keywords
-    "!!" "!" "+" "--" ":" ";" "<" "<=" "==" "=>" "?" "[" "\<comment>" "\<equiv>" "\<leftharpoondown>" "\<rightharpoonup>" "\<rightleftharpoons>"
+    "!!" "!" "+" ":" ";" "<" "<=" "==" "=>" "?" "[" "\<comment>" "\<equiv>" "\<leftharpoondown>" "\<rightharpoonup>" "\<rightleftharpoons>"
     "\<subseteq>" "]" "attach" "binder" "in" "infix" "infixl" "infixr" "is" "open" "output"
     "overloaded" "pervasive" "premises" "structure" "unchecked"
   and "private" "qualified" :: before_command
   and "assumes" "constrains" "defines" "fixes" "for" "if" "includes" "notes" "rewrites"
     "obtains" "shows" "when" "where" "|" :: quasi_command