language-implementation

From the Google Open Source Blog : PyPy is a reimplementation of Python in Python, using advanced techniques to try to attain better performance than CPython. Many years of hard work have finally paid off. Our speed results often beat CPython, ranging from being slightly slower, to speedups of up to 2x on real application code, to speedups of up to 10x on small benchmarks. How is this possible? Which Python implementation was used to implement PyPy? CPython ? And what are the chances of a PyPyPy or PyPyPyPy beating their score? (On a related note... why would anyone try something like this?)

This question already has an answer here: How do foreach loops work in C#? 7 answers How exactly is foreach implemented in C#? I imagine a part of it looking like: var enumerator = TInput.GetEnumerator(); while(enumerator.MoveNext()) { // do some stuff here } However I'm unsure what's really going on. What methodology is used for returning enumerator.Current for each cycle? Does it return [for each cycle] or does it take an anonymous function or something to execute the body of foreach ? It doesn't use an anonymous function, no. Basically the compiler converts the code into something broadly

I am intrigued by how the C++ exception handling mechanism works. Specifically, where is the exception object stored and how does it propagate through several scopes until it is caught? Is it stored in some global area? Since this could be compiler specific could somebody explain this in the context of the g++ compiler suite? Implementations may differ, but there are some basic ideas that follow from requirements. The exception object itself is an object created in one function, destroyed in a caller thereof. Hence, it's typically not feasible to create the object on the stack. On the other

I am just trying to understand why all fields defined in an Interface are implicitly static and final . The idea of keeping fields static makes sense to me as you can't have objects of an interface but why they are final (implicitly)? Any one knows why Java designers went with making the fields in an interface static and final ? Adriaan Koster An interface can't have behavior or state because it is intended to specify only an interaction contract, no implementation details. No behavior is enforced by not allowing method/constructor bodies or static/instance initializing blocks. No state is