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From: David Shepherd <des@inmos.co.uk>
Message-Id: <17818.9307070953@frogland.inmos.co.uk>
Subject: Re: automatic con(de)structors ?
To: shaw@cs.ucdavis.edu (Rob Shaw)
Date: Wed, 7 Jul 1993 10:53:14 +0100 (BST)
Cc: info-hol@cs.uidaho.edu
In-Reply-To: <9307070115.AA11787@toadflax.cs.ucdavis.edu> from "Rob Shaw" at Jul 6, 93 06:15:02 pm
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Rob Shaw has said:
> If I define:
> 
> let Vstate_Axiom = define_type 
>     `Vstate`
>     `Vstate = VSTATE registers memory pc`;;
> 
> Is there anyway to get the following automatically? Perhaps something
> undocumented in contrib?
> 
> let get_regs = new_recursive_definition
>     false Vstate_Axiom `get_regs`
>    "get_regs (VSTATE regs mem pc) = regs";;
> 
> let get_mem = new_recursive_definition
>     false Vstate_Axiom `get_mem`
>    "get_mem (VSTATE regs mem pc) = mem";;
> 
> let get_pc = new_recursive_definition
>     false Vstate_Axiom `get_pc`
>    "get_pc (VSTATE regs mem pc) = pc";;
> 
> Just the obvious destructors corresponding the the type definition.

take a look at Phil Windley's datatype library ... (I think) this does
the sort of things you are wanting.

Having said this ... it doesn't seem to be in the contrib directory
at cl.cam.ac.uk ... though, it was posted on this mailing list a few
months back so you could find it by trawling through the info-hol
library. I'm afraid I don't have a copy.

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