[Oberon] Oberon Wiki ; what happend with WITH
chris at gcjd.de-web.ws
Sun Jan 9 23:44:40 CET 2011
Frans-Pieter Vonck wrote:
>I also found that in the Oberon07 reports that the WITH statement is
>omitted, however there is no explanation why this was done. From the
>examples of the Wiki pages I could not conclude myself why leaving WITH
>out of the language was a good thing.
I think there are several reasons.
1) It's syntactic sugar somewhat and not often needed from my
2) It has non local effect changing a variable's type in a
subscope, which is not a good idea. This is a concept
that is otherwise absent in Oberon. It also makes reading source harder
if variables may not have their declared type sometimes.
3) There is a problem in the ETH compilers described here:
>Wikipedia does not show an example of the use of IS in comparison to the
If T1 is an extensions of T0 I would say:
v : T0;
WITH v : T1 DO "use v" END;
IF v IS T1 THEN "use v(T1)" END;
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