This has been answered in excruciating detail by Eric Lippert in a blog post that has since been removed. Here is the archived version. There is also another subtler point about value types and instance operators. Static operators make this kind of code possible: class Blah { int m_iVal; public static Blah operator+ (Blah l, … Read more
There are a lot of misconceptions here, both in the question itself and in the several answers. Let me begin by examining the premise of the question. The question is “why do we need the new keyword in C#?” The motivation for the question is this fragment of C++: MyClass object; // this will create … Read more
This is Brad Cox. My original answer misunderstood the question. I assumed reallyFast was a hardcoded extension to trigger faster messaging, not a kind of syntactic sugar. The real answer is that Smalltalk didn’t support it, perhaps because its parser couldn’t deal with the (assumed) ambiguity. Although OC’s square brackets would remove any ambiguity, I … Read more
Dim originally (in BASIC) stood for Dimension, as it was used to define the dimensions of an array. (The original implementation of BASIC was Dartmouth BASIC, which descended from FORTRAN, where DIMENSION is spelled out.) Nowadays, Dim is used to define any variable, not just arrays, so its meaning is not intuitive anymore.
Try C#7’s Pattern Matching. Using your example: if (new StringBuilder(“test”) is var sb && sb != null) { Console.WriteLine(sb); }
‘for backwards compatibility’ seems a sufficient reason for the type erasure of class generic types – it is needed e.g. to allow you to return an untyped List and pass it to some legacy code. The extension of this to generic methods seems like a tricky sub-case. The JLS snippet from 4.8 (which you quote) … Read more
It appears that simplicity was the main reason. From this interview: Gosling: For me as a language designer, which I don’t really count myself as these days, what “simple” really ended up meaning was could I expect J. Random Developer to hold the spec in his head. That definition says that, for instance, Java isn’t … Read more
Both newtype and the single-constructor data introduce a single value constructor, but the value constructor introduced by newtype is strict and the value constructor introduced by data is lazy. So if you have data D = D Int newtype N = N Int Then N undefined is equivalent to undefined and causes an error when … Read more
Because I may write Foo and its friend Bar (thus there is a trust relationship). But do I trust the people who write classes that are derived from Bar? Not really. So they should not inherit friendship. Any change in the internal representation of a class will require a modification to anything that is dependent … Read more
So, the “inheritance” of static members merely looks like namespace pollution That’s right, except that one guy’s pollution is another guy’s added spicy flavouring. I think Martin Fowler, in his work on DSLs, has suggested using inheritance in this way to allow convenient access to static methods, allowing those methods to be used without class … Read more