Path: utzoo!attcan!uunet!mitel!sce!cognos!kain
From: kain@cognos.uucp (Kai Ng)
Newsgroups: comp.lang.eiffel
Subject: Re: redefinition and renaming
Keywords: redefinition, renaming, dynamic binding
Message-ID: <5529@corona.UUCP>
Date: 10 Mar 89 21:48:25 GMT
References: <2431@isis.UUCP> <5434@corona.UUCP> <694@m3.mfci.UUCP> <5506@corona.UUCP>
Reply-To: kain@cognos.UUCP (Kai Ng)
Organization: Cognos Inc., Ottawa, Canada
Lines: 123

Sorry folks. The problem is my hands can type faster than my mind can think.
The example provided in my previous article will not compiled if just
entered as is. Thanks to Alan Myrvold (sp ?), my co-worker, who pointed 
that out to me.

But I did code something correctly and got the result before I opened my mouth
:-(

In article <5506@corona.UUCP> kain@cognos.UUCP (Kai Ng) writes:
>
>CLASS B
>
>INHERIT
>    A REDEFINE classNumber
>
>FEATURE
>
>    classNumber: Integer IS 2;
>
>END -- Class B
>-------------------------------------------------------------------------
>CLASS C
>
>INHERIT
>    A REDEFINE classNumber
>
>    ...
>    classNumber: Integer IS 3
>    ...
>-------------------------------------------------------------------------

You would get the following error message:

"b", 6: Constant feature may not be redefined: classnumber
*** es: error in pass2

Anyway the following is the correct example classes:

--------------------------------------------------------------------------
CLASS A

FEATURE

	classNumber: Integer IS
		DO
			Result := 1;
		END; -- classNumber

	print IS
		EXTERNAL
			printf LANGUAGE "C";
		DO
			printf ("%d", classNumber);
		END; -- print

END -- Class A

--------------------------------------------------------------------------
CLASS B

INHERIT
	A REDEFINE classNumber

FEATURE

	classNumber: Integer IS
		DO
			Result := 2;
		END; -- classNumber

END -- Class B

--------------------------------------------------------------------------
CLASS C

INHERIT
	A REDEFINE classNumber

FEATURE

	classNumber: Integer IS
		DO
			Result := 3;
		END; -- classNumber

END -- Class C

--------------------------------------------------------------------------
CLASS D

INHERIT
	B RENAME print AS printB,
			 classNumber AS classB;
	C RENAME print AS printC,
             classNumber AS classC

FEATURE

	Create IS
		EXTERNAL
			printf LANGUAGE "C";
		DO
			printf ("\n printB prints ");  printB;
			printf ("\n printC prints ");  printC;
		END; -- Create

END -- Class D

--------------------------------------------------------------------------

Class D should be compiled as the rootClass and the following output should
be expected:

 printB prints 3
 printC prints 3

--------------------------------------------------------------------------

-- 
Kai Ng                 P.O. Box 9707         UUCP: uunet!mitel!sce!cognos!kain
Cognos Incorporated    3755 Riverside Dr.
(613) 738-1440         Ottawa, Ontario,
 ext. 6114             CANADA  K1G 3Z4