Ryan Joseph via fpc-pascal <fpc-pas...@lists.freepasca023815.html ieb am Mo., 23. Dez. 2019, 06:01:
> > > > On Dec 22, 2019, at 5:26 AM, Sven Barth via fpc-pascal < > fpc-pascal@lists.freepascal.org> wrote: > > > > You don't seem to understand what implementing an interface means in > Object Pascal. It means that a class can be cast to an interface. It does > *not* mean that the interface's methods are available from that class. > > I guess I'm not seeing the design pattern which they was invented for and > I've never come across it in my own work. Not against the idea in any way > however. > > My mind went in the same direction as Adriaan's did when I saw > "implements" I thought that one class could be built from many smaller > classes but share the same namespace (like in multiple inheritance or > entity/component designs). If a class implements an interface via a > delegate then I would expect this to function the same as inheritance, i.e. > the namespaces are merged and share functions. Doesn't that make sense? > It does make sense, but not in the context of interfaces. They are not there to provide implementations, but to provide a known API to the user. > Maybe what I mean to say is that there's a need for a delegation syntax > that functions like multiple inheritance and avoids the traps of deeply > nested single inheritance hierarchies. Does anyone else agree? > What might be more interesting in this context than multiple inheritance is the concept of aspects (aka aspect oriented programming though you might also want to look for "mixin"; there's an old thread about that: https://lists.freepascal.org/fpc-pascal/2009-December/023815.html). If we could find an agreeable syntax and implementation for that then we'd be potentially inclined to include that as a new feature as there had been experiments for that in the past. Regards, Sven >
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