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copied!<p>I think you're looking at it backwards.</p> <p>Nobody sat down and said "OK, we need slicing in this language." Slicing in itself isn't a language feature; it's the name of what happens when you meant to use objects polymorphically but instead went wrong and copied them. You might say that it's the name of a programmer bug.</p> <p>That objects can be copied "statically" is a fundamental feature of C++ and C, and you wouldn't be able to do much otherwise.</p> <p>Edit: [by Jerry Coffin (hopefully Tomalak will forgive my hijacking his answer a bit)]. Most of what I'm adding is along the same lines, but a bit more directly from the source. The one exception (as you'll see) is that, strangely enough, somebody <em>did</em> actually say "we need slicing in this language." Bjarne talks a bit about slicing in <em>The Design and Evolution of C++</em> (§11.4.4). Among other things he says:</p> <blockquote> <p>I'm leery of slicing from a practical point of view, but I don't see any way of preventing it except by adding a very special rule. Also, at the time, I had an independent request for exactly these "slicing semantics" from Ravi Sethi who wanted it from a theoretical and pedagogical point of view: Unless you can assign an object of a derived class to an object of its public base class, then that would be the only point in C++ where a derived object can't be used in place of a base object.</p> </blockquote> <p>I'd note that Ravi Sethi is one of the authors of the dragon book (among many other things), so regardless of whether you agree with him, I think it's easy to understand where his opinion about language design would carry a fair amount of weight.</p>

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