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Article View: comp.lang.modula2
Article #1715

Re: Standard Modula2

#1715
From: Warwick Allison
Date: Wed, 30 Jan 1991 23:34
24 lines
1609 bytes
In <1991Jan30.091656.4348@mack.uit.no> torbjorn@forit.forut.no (Torbjorn Sund) writes:


>Jon.Guthrie@p15.f20.n226.z1.fidonet.org (Jon Guthrie) writes:
> 
>> All I want to do is be able to assign any quantity of type ADDRESS to an
>> opaque type.  I also want to be able to test an opaque type for equality to
>> NIL.
> 
>Who says that an opaque type is assignment or storage equivalent to ADDRESS?
>At least one compiler (FTL) did not impose the restriction that an
>opaque type be implemented as a pointer.

That's right, opaque is OPAQUE - It represents a level of abstraction,
which you cannot circumvent, you shouldn't really be using assignment
operations with an opaque type.  If you need some sort of ADDRESS from
the opaque type, then the module exporting the type should given you
a function to do that, if not, then you should make NO ASSUMPTIONS
about the opaque type.
--
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References: <1180.279FE75C@puddle.fidonet.org> <1991Jan25.174802.11700@m2xenix.psg.com> <1991Jan30.091656.4348@mack.uit.no>

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From: warwick@batserver.cs.uq.oz.au (Warwick Allison)
Newsgroups: comp.lang.modula2
Subject: Re: Standard Modula2
Message-ID: <7091@uqcspe.cs.uq.oz.au>
Date: 30 Jan 91 23:34:58 GMT
References: <1180.279FE75C@puddle.fidonet.org> <1991Jan25.174802.11700@m2xenix.psg.com> <1991Jan30.091656.4348@mack.uit.no>
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