sig
type cst = C_str of string | W_str of int64 list
val pretty : Format.formatter -> Cstring.cst -> unit
val str_len : Cstring.cst -> Lang.F.term -> Lang.F.pred
val str_val : Cstring.cst -> Lang.F.term
val str_id : Cstring.cst -> int
val char_at : Cstring.cst -> Lang.F.term -> Lang.F.term
val cluster : unit -> Definitions.cluster
end