From: joe@petsd.UUCP (Joe Orost)
Subject: Re: Ambiguous use of dereference in Ada
Date: Wed, 24-Jul-85 10:41:11 EDT [thread overview]
Date: Wed Jul 24 10:41:11 1985
Message-ID: <598@petsd.UUCP> (raw)
In-Reply-To: 38000019@gypsy.UUCP
In article <38000019@gypsy.UUCP> rosen@gypsy.UUCP writes:
> ...
> type stupid is
> record
> a: integer;
> b: float;
> end record;
> type stupid_ptr is access stupid;
> c1, c2: integer;
> xxx: stupid_ptr;
> begin
> c1 := xxx.a; --1--
> c2 := xxx.all.a; --2--
> ...
Some quotes from the bible:
4.1.3(6) (b) A component of a record:
(7) The selector must be a simple name denoting a
component of a record object or value. The prefix
must be APPROPRIATE FOR THE TYPE of this object or
value.
(11) (d) An object designated by an access value:
(12) The selector must be the reserved word ALL. The
value of the prefix must belong to an access type.
4.1(6) A prefix is said to be APPROPRIATE FOR A TYPE in
either of the following cases:
(7) o The type of the prefix is the type considered.
(8) o The type of the prefix is an access type whose
designated type is the type considered.
In your example, the first dereference is legal because of 4.1.3(7) & 4.1(8).
The second dereference is legal because of 4.1.3(12) & 4.1.3(7) & 4.1(7).
QED.
regards,
joe
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prev parent reply other threads:[~1985-07-24 14:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
1985-07-22 14:06 Ambiguous use of dereference in Ada rosen
1985-07-24 14:41 ` Joe Orost [this message]
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