Re: Suggestion

From: Alf P. Steinbach (alfps_at_start.no)
Date: 09/07/04 

Date: Tue, 07 Sep 2004 03:26:32 GMT

* Eivind Grimsby Haarr:
>
> When using polymorphism in a big system, I have sometimes come across
> problems when changing the signature of the function in the base class,
> and forgetting to change the signature of the derived functions
> accordingly. (Most often when only some of the derived classes redefine
> it.) Accessing the objects with base class pointers, the version in the
> base class is called, which is not what I wanted. This is most often very
> difficult to detect.
>
> This has made me come up with an idea for a compiler/language feature that
> would fix this problem: A keyword in front of the derived function that
> says that this function is derived from a base class, and the compiler
> should issue an error if a function with a similar signature doesn't
> exist in one of the base classes.
>
> What do you think about this idea? Is it just too much pain for a rare
> problem?

It's always a good idea to catch errors at the earliest time possible,
preferably analysis and design, but if not, then compile-time.

Your idea is a Good One (TM) and is implemented in .NET languages such as
VB.NET and C#, in the latter using the keywords "override" (override) and
"new" (shadow).

Getting it into C++, that's another matter... ;-) 

-- 
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Relevant Pages

  • Re: Suggestion
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    (comp.lang.cpp)
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    (microsoft.public.dotnet.languages.csharp)
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