Re: Overring function and its returned type

[Maciej Sobczak <see.my.homepage@gmail.com>]

W dniu piątek, 16 listopada 2012 13:39:50 UTC+1 użytkownik Peter C. Chapin napisał:

> Yet I wonder if 
> it increases the risk of an "unrelated" change breaking an existing code 
> base by introducing an ambiguity where none existed before.

I'm not sure - probably, today, it is too late to add this to the language for the reasons that you have mentioned. However, this feature could have been safely added together with other OO-related features, as the whole support for OO was new in the language and there was no existing codebase that would break.

An interesting property of Ada, and what makes this issue more difficult than in C++ is that Ada supports out parameters, which from the language design point of view should work like return values. Covariant return types are easy to picture, but covariant out parameters? Hm... Maybe this is where things would start to shake.

-- 
Maciej Sobczak * http://www.msobczak.com * http://www.inspirel.com