[Oberon] Dynamic type of record var parameter

[Diego Sardina]

Yes, the last should be r2

-- 
  Diego Sardina

On Mon, Jan 11, 2021, at 11:44 PM, chris wrote:
> Hello,
> 
> please consider the following test of dynamic type of record variable 
> parameters:
> 
> MODULE Test;
> 
>   IMPORT Texts, Oberon;
> 
> TYPE
> 	r0 = RECORD i : INTEGER; END;
> 	r1 = RECORD (r0) x : REAL END;
> 	r2 = RECORD (r1) c : CHAR END;
> 	p0 = POINTER TO r0;
> 	p1 = POINTER TO r1;
> 	p2 = POINTER TO r2;
> 
> VAR W : Texts.Writer;
> 
> PROCEDURE check(VAR r : r0);
> BEGIN
> 	IF r IS r2 THEN Texts.WriteString(W, "is r2") ELSIF r IS r1 THEN
> 		Texts.WriteString(W, "is r1")
> 	ELSIF r IS r0 THEN Texts.WriteString(W, "is r0") END;
> 	Texts.WriteLn(W)
> END eins;
> 
> PROCEDURE do* ();
> VAR p : p0;  r : r0; q : p2; t : r2;
> BEGIN
> 	NEW(p); NEW(q);
> 	check(t);
> 	check(p^);
> 	check(q^);
> 	p := q;  check(p^);
> 	Texts.Append(Oberon.Log, W.buf);
> END do;
> 
> BEGIN
> 	Texts.OpenWriter(W);
> END Test.
> 
> Output from Oberon 2013 emulator is:
> is r2
> is r0
> is r2
> is r0
> 
> What  surprises me is the last one. The dynamic type is r2 not r0. It 
> looks like the compiler uses the static type from the local variable p 
> instead of the dynamic type of p^. Is this intended behavior?
> 
> Greetings, chris
> --
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