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From: belle@skipper.dfrf.nasa.gov (Steve Belle)
Newsgroups: comp.lang.eiffel
Subject: Re: Class STRING bug
Message-ID: <578@skipper.dfrf.nasa.gov>
Date: 24 Jul 90 23:25:45 GMT
References: <2339@dover.sps.mot.com>
Sender: news@skipper.dfrf.nasa.gov
Reply-To: belle@skipper.dfrf.nasa.gov
Organization: NASA Ames-Dryden Flight Research Facility, Edwards AFB, CA
Lines: 25


In article <2339@dover.sps.mot.com>, shelley@atc.sps.mot.com (Norman K.
Shelley) writes:
|> class NEW_STRING
|> inherit
|> 	STRING;	-- notice that Create is not renamed
|> feature
|> ... 
|> end; -- NEW_STRING
|> 
|> Object of class NEW_STRING does not use STRING's Create (or allocate) to
|> allocate some string storage space. When equal, putstring, etc. are
applied to
|> this object, the system will crash with a segmentation error!

On page 56 of "Eiffel: The Language", it states that "Create is never
inherited, as
each class usually needs to have its own method for create instances,
independent
from its parents'."   In Eiffel 2.2, the above is not a bug in STRING, but an 
incorrect implementation of the inheritence mechanism.  There is a margin note 
indicating a change in this mechanism in version 3.

Steve Belle
belle@skipper.dfrf.nasa.gov