Commit 29c14865 authored by Pietro Abate's avatar Pietro Abate
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[r2003-07-28 14:35:03 by cvscast] Empty log message

Original author: cvscast
Date: 2003-07-28 14:35:03+00:00
parent 1d5211cc
(* In CDuce the expression "ref T exp" returns a reference *)
(* to the result of "exp" and has type "ref T" provided that *)
(* "exp" is of type "T" *)
let stack = ref [Int*] []
(* References come equipped with three operators: ":=" *)
(* (assignment), "!" (dereferencing), ";" (sequencing) *)
let fun push(x : Int) : [] =
stack := [x, !!stack]
let fun pop ([] : []) : Int =
match !stack with [x ;y] -> stack := y; x | _ -> raise "Empty stack"
(* In [ pattern ;y] the variable y captures the rest of the *)
(* sequence. It is equivalent to [pattern y::_*] *)
(* *)
(* Since sequences are encoded by pairs, we could write *)
(* the following [deprecated] equivalent definitions *)
(*
let fun push(x : Int) : [] =
stack := (x, !stack)
let fun pop ([] : []) : Int =
match !stack with (x, y) -> stack := y; x | _ -> raise "Empty stack"
*)
;;
......
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