module Var:sig..end
type t 
APRON Variables
val of_string : string -> tConstructor
val compare : t -> t -> intComparison function. Implements a total order and returns -1, 0, or 1.
val to_string : t -> stringConversion to string
val hash : t -> intHash function
val print : Stdlib.Format.formatter -> t -> unitPrinting function
val set_var_operations : unit -> unitInitialisation of abstract type operations in C library