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Module Opaque


module Opaque: sig  end
Opaque types for int and string. This module provides a convenient way to convert int or string types to abstract types.

Motivation: type int may be used for representing several kinds of data. Confusion is easy, so we often need to make it abstract, while keeping:

This solution was suggested by Jacques Garrigue. What the user has to do is open Opaque and then use a type parameter to define the specialized version of int or string. We will write the type declarations as type port = [`Port] int_t or type date = [`Date] int_t. Data is converted with the int_t and t_int polymorphic functions as in let port : port = int_t 0.
Author(s): Martin Jambon


Opaque ints 


type 'a int_t
data of type 'a int_t has the same internal representation as type int.
val int_t : int -> 'a int_t
val t_int : 'a int_t -> int
val any_int : 'a int_t -> 'b int_t
int_t, t_int and any_int are type conversion functions.
val add : 'a int_t -> 'a int_t -> 'a int_t
val sub : 'a int_t -> 'a int_t -> 'a int_t
val mul : 'a int_t -> 'a int_t -> 'a int_t
val div : 'a int_t -> 'a int_t -> 'a int_t
val neg : 'a int_t -> 'a int_t
add, sub, mul, div and neg are the equivalents of ( + ), ( - ), ( * ), ( / ) and ( ~- ).
val successor : 'a int_t -> 'a int_t
val predecessor : 'a int_t -> 'a int_t
val increment : 'a int_t Pervasives.ref -> unit
successor, predecessor and increment are the equivalents of ( + ), ( - ), ( * ), ( / ) and ( ~- ).
val print_int_t : 'a int_t -> unit


Opaque strings 


type 'a string_t
data of type 'a string_t has the same internal representation as type string.
val string_t : string -> 'a string_t
val t_string : 'a string_t -> string
val any_string : 'a string_t -> 'b string_t
int_string, t_string and any_string are type conversion functions.
val concat : 'a string_t -> 'a string_t -> 'a string_t
val concat_list : string -> 'a string_t list -> 'a string_t
concat and concat_list are equivalents of ( ^ ) and String.concat.
val print_string_t : 'a string_t -> unit