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INTERFACE QPromise;

FROM Quake IMPORT Error;
IMPORT Thread, Process;

deferred execution in Quake see delayed evaluation in Abelson and Sussman, Structure and Interpretation of Computer Programs, for the inspiration to this.

Author : Mika Nystrom <mika@alum.mit.edu>

TYPE
  ExitCode = Process.ExitCode;

  T = OBJECT METHODS
    fulfil() : ExitCode RAISES { Error, Thread.Alerted }
    (* force the promise *)
  END;

  Empty <: T;
  (* empty is a promise that does nothing when forced *)

CONST Brand = "QPromise";

CONST Equal : PROCEDURE(a, b : T) : BOOLEAN = NIL;

END QPromise.