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From: Jacques Garrigue <garrigue@math.nagoya-u.ac.jp>
To: jeremy.yallop@ed.ac.uk
Cc: caml-list@yquem.inria.fr
Subject: Re: [Caml-list] Troublesome nodes
Date: Fri, 18 Jul 2008 22:02:14 +0900 (JST)	[thread overview]
Message-ID: <20080718.220214.241921104.garrigue@math.nagoya-u.ac.jp> (raw)
In-Reply-To: <488066C9.4050904@ed.ac.uk>

From: Jeremy Yallop <jeremy.yallop@ed.ac.uk>

> I don't yet understand exactly how private abbreviations are supposed to 
> work.  The currently implemented behaviour doesn't accomplish what I 
> understand to be the intention.  For example, given
> 
>     module Nat :
>     sig
>       type t = private int
>       val z : t
>       val s : t -> t
>     end =
>     struct
>       type t = int
>       let z = 0
>       let s = (+) 1
>     end
> 
> we can write
> 
>     # (((Nat.z : Nat.t :> int) - 1) :> Nat.t);;
>     - : Nat.t = -1

It looks like you've found a serious bug in the current
implementation. Actually you don't even need a coercion:

  # (((Nat.z : Nat.t :> int) - 1) : Nat.t);;
  - : Nat.t = -1

This should certainly not be accepted, as you can see by writing

# (((Nat.z : Nat.t :> int) - 1) : int :> Nat.t);;  (* fails *)

I think I know the reason, which is probably related to the way
abbreviation expansions are cached, but this needs more investigating.

Jacques Garrigue


  reply	other threads:[~2008-07-18 13:02 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-07-11 20:39 Dario Teixeira
2008-07-11 21:20 ` [Caml-list] " Jeremy Yallop
2008-07-12 12:37   ` Dario Teixeira
2008-07-12 13:25     ` Jacques Carette
2008-07-12 16:44     ` Wolfgang Lux
2008-07-12 18:21       ` Dario Teixeira
2008-07-12 18:27         ` Jeremy Yallop
2008-07-12 18:58       ` Jacques Carette
2008-07-11 23:11 ` Zheng Li
2008-07-13 14:32 ` [Caml-list] " Dario Teixeira
2008-07-13 17:39   ` Dario Teixeira
2008-07-13 21:10     ` Jon Harrop
2008-07-14 15:11       ` Dario Teixeira
2008-07-14 18:52         ` Dario Teixeira
2008-07-14 19:37           ` Jeremy Yallop
2008-07-16 21:22             ` Dario Teixeira
2008-07-17  0:43             ` Jacques Garrigue
2008-07-17 10:59               ` Jeremy Yallop
2008-07-18  2:34                 ` Jacques Garrigue
2008-07-18  9:47                   ` Jeremy Yallop
2008-07-18 13:02                     ` Jacques Garrigue [this message]
2008-07-18 13:55                       ` Jacques Garrigue
2008-07-19  2:15                         ` Jacques Garrigue
2008-07-17 16:12               ` Dario Teixeira
2008-07-18  2:27                 ` Jacques Garrigue
2008-07-18 13:09                   ` Dario Teixeira
2008-07-18 17:36                     ` Dario Teixeira
2008-07-19  2:23                       ` Jacques Garrigue
2008-07-19  8:43                         ` Dario Teixeira

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