RE: incompatible assignement (POINTER TO LIMITED RECORD)

From: null <">
Date: Fri, 26 Oct 2007 13:44:15 +0000

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Gerald writes:

[...]
> This problem is not limited to... LIMITED records.
> It's just that a^ and b^ are not assignment compatible.
> As 'a' may be an extension of 'b' (at least in theory,
> but I suppose the compiler doesn't verify this point),
> 'a^' may be bigger than 'b^', so that the assignment is
> impossible. If you remove the word 'LIMITED', there may
> be no extension of 'Ball', and the problem vanishes.

so I tried:

        b^ := a(Ball)^;

but that yields also: "incompatible assignment" although the
report says (in Sec. 8.1):


> A type guard v(T) asserts that the dynamic type of
> v is T (or an extension of T), i.e., program execution is
> aborted, if the dynamic type of v is not T (or an extension
> of T). Within the designator, v is then regarded as having
> the static type T.

which implies to me that the assignment should be possible.

regards

--
	Bernhard Treutwein, IuK, Ref. III A 3
	Bernhard.Treutwein(at)verwaltung uni-muenchen de
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Received on Fri Oct 26 2007 - 15:44:15 UTC