let regexp ligature_char = [ "'`~!?@*()[]<>-+=|:;.,/\"" ]
let regexp ligature = ligature_char ligature_char+
-let regexp ident_decoration = '\'' | '!' | '?' | '`'
+let regexp ident_decoration = '\'' | '?' | '`'
let regexp ident_cont = ident_letter | xml_digit | '_'
let regexp ident = ident_letter ident_cont* ident_decoration*