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From: heiser@iis.UUCP (Gernot Heiser)
Newsgroups: comp.lang.modula2
Subject: Re: Portable Oberon compiler
Message-ID: <774@jupiter.iis.UUCP>
Date: 7 Feb 89 20:42:00 GMT
References: <INFO-M2%89012710550179@DB0TUI11> <772@jungfrau.UUCP>
Reply-To: heiser@iis.ethz.ch (Gernot Heiser)
Organization: Integrated Systems Lab., ETH Zuerich
Lines: 27
Summary:
 Expires:

In article <772@jungfrau.UUCP> marvin@jungfrau.UUCP writes:
}  [ stuff deleted ]
} To avoid this, the portable Oberon compiler will have a
}slight modification to the language: you have to add a compiler hint in
}the definition part. It will then look like this (referring to the
}example in the paper): 
}
}TYPE	Viewer = RECORD
}		   width, height : INTEGER;
}		   [8]
}		 END;
}
}The number indicates the size of the record as it will be in the
}implementation part.

This looks like a real portability feast. Assuming this "hint" indicates the
number of bytes to reserve for the record, this number is highly hardware (and
probably compiler) dependent. Assuming the private part consists of two
INTEGERs, the size of the number depends on the size (in bytes) of an INTEGER
item. Is this _really_ preferrable to an visible "private part" (e.g. as done
in Ada) where at least your code is portable?

-- 
Gernot Heiser                   Phone:       +41 1/256 23 48
Integrated Systems Laboratory   CSNET/ARPA:  heiser%iis.ethz.ch@relay.cs.net
ETH Zuerich                     UUCP (new):  heiser@iis.uucp
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