language-features

What makes Scala such a wonderful language, other than the type system? Almost everything I read about the language brings out 'strong typing' as a big reason to use Scala, but there has to be more than that. What are some of the other compelling and/or cool language features that make Scala a really useful tool? Here are some of the things that made me favour Scala (over, say, usual Java): a) Type inference. The Java way of doing it: Map<Something, List<SomethingElse>> list = new HashMap<Something, List<SomethingElse>>() .. is rather verbose compared to Scala. The compiler should be able to

Small preamble. I was good java developer on 1.4 jdk. After it I have switched to another platforms, but here I come with problem so question is strongly about jdk 1.6 (or higher :) ). I have 3 coupled class, the nature of coupling concerned with native methods. Bellow is example of this 3 class public interface A { public void method(); } final class AOperations { static native method(. . .); } public class AImpl implements A { @Override public void method(){ AOperations.method( . . . ); } } So there is interface A, that is implemented in native way by AOperations, and AImpl just delegates

I'd like something like this: each[i_, {1,2,3}, Print[i] ] Or, more generally, to destructure arbitrary stuff in the list you're looping over, like: each[{i_, j_}, {{1,10}, {2,20}, {3,30}}, Print[i*j] ] Usually you want to use Map or other purely functional constructs and eschew a non-functional programming style where you use side effects. But here's an example where I think a for-each construct is supremely useful: Say I have a list of options (rules) that pair symbols with expressions, like attrVals = {a -> 7, b -> 8, c -> 9} Now I want to make a hash table where I do the obvious mapping of

I know that in JavaScript, creating a for loop like this: for(int i = 0; i < arr.length; i++) is costly as it computes the array length each time. Is this behavior costly in c# for lists and arrays as well. Or at compile-time is it optimized? Also what about other languages such as Java, how is this handled? It is not costly in C#. For one thing, there is no “calculation“: querying the length is basically an elementary operation thanks to inlining. And secondly, because ( according to its developers ), the compiler recognizes this pattern of access and will in fact optimize any (redundant)

I need to know a correct name for this cool feature that some languages provide. FYI: In some languages it is possible to do a multiple assignments by assigning a structure of values to a structure of "variables". In the example in the question title it assigns "foo" to foo and "bar" to bar. It's generally called destructuring bind in functional languages (which don't have assignments) and destructuring assignment in imperative languages. Some languages provide subsets of that feature and then call it something different. For example, in Python it works with Tuples, Lists or Sequences and is