[Oberon] Message Objects in Oberon

[Jörg Straube]

Hi

The beauty of Oberon OS is, that you can extend it. Eg in Native Oberon there was an extension of the Text files called "folds". With folds it was possible to make different versions of the same source code (eg a Windows or Linux version of Display.Mod or a German and English version of the compiler), choose and enable the needed version before compilation.
(A little bit comparable to C's #ifdef)

At compile time of TextFrames.Mod this folds extension was not known. By using messages and handlers you can e.g. extend Texts and TextFrames without touching the binaries of those modules.

Jörg

> Am 28.03.2016 um 06:45 schrieb Srinivas Nayak <sinu.nayak2001 at gmail.com>:
> 
> Dear All,
> 
> Oberon OS source code uses Handlers and Message objects extensively.
> We know, they are costly (run time type check),
> unhandled messages consume more time even (sequential check of if else ladder),
> compilers can't catch the errors made (inappropriate message sent to an object).
> Still how do we consciously decide to use message objects more in Oberon (which benefits outweigh all these)?
> 
> 
> 
> With thanks and best regards,
> 
> Yours sincerely,
> Srinivas Nayak
> 
> Home: http://www.mathmeth.com/sn/
> Blog: http://srinivas-nayak.blogspot.in/
> --
> Oberon at lists.inf.ethz.ch mailing list for ETH Oberon and related systems
> https://lists.inf.ethz.ch/mailman/listinfo/oberon
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