generic-programming

Is there a way one could avoid type erasure and get access to a type parameter? public class Foo<T extends Enum<?> & Bar> { public Foo() { // access the template class here? // i.e. : baz(T.class); // obviously doesn't work } private void baz(Class<T> qux) { // do stuff like T[] constants = qux.getEnumConstants(); ... } } I need to know about T , and do things with it. Is it possible, and if so, how can it be done without passing in the class in the constructor or anywhere besides the parameter? EDIT: The main purpose of this question is to find out if there is any practical way around type

Actually I've a problem with compiling some library with intel compiler. This same library has been compiled properly with g++. Problem is caused by templates. What I'd like to understand is the declaration of **typename** as not template function parameter and variable declaration inside function body example: void func(typename sometype){.. ... typename some_other_type; .. } Compilation this kind of code produce following errors (intel),(gcc doesn't claim): I've got following errors ../../../libs/log/src/attribute_set.cpp(415): error: no operator "!=" matches these operands operand types are

I'm using generics rather long time but I've never used construction like List<? super T> . What does it mean? How to use it? How does it look after erasure? I also wonder: is it something standard in generic programming (template programming?) or it's just a java 'invention'? Does c#, for example, allow similar constructions? This construct is used when you want to consume items from a collection into another collection. E.g. you have a generic Stack and you want to add a popAll method which takes a Collection as parameter, and pops all items from the stack into it. By common sense, this code

I've used the Scrap Your Boilerplate and Uniplate libraries in the Haskell programming language, and I would find that form of generic programming over discriminated unions to be really useful. Is there an equivalent library in the f# programming language? Not that I know of; without support built-in to the language/compiler, I expect the only alternative is a reflection-based version. (I don't know how Uniplate is implemented - do you?) Here's the code for a reflection-based version based on the example from the original presentation. I have not thought deeply about its limitations, but this

This is not exactly a technical question, since I know C kind of enough to do the things I need to (I mean, in terms of not 'letting the language get in your way'), so this question is basically a 'what direction to take' question. Situation is: I am currently taking an advanced algorithms course, and for the sake of 'growing up as programmers', I am required to use pure C to implement the practical assignments (it works well: pretty much any small mistake you make actually forces you to understand completely what you're doing in order to fix it). In the course of implementing, I obviously run

Assuming you have case classes like the following case class Test1(a:String,b:Int,c:Char) case class Test2(a:String,b:Int) And you instantiate the classes with the following variables val test1 = Test1("first",2,'3') val test2 = Test2("1st",20) Is there a way to use the .copy method (or otherwise), to apply the variables inside Test2 to Test1, something like val test3 = test1.copy(test2) //Note this isn't valid scala code // Result should be ("1st",20,'3') If this isn't possible in pure scala, how would it be done in Shapeless 1/2 (current code is in Shapeless 1, however we are planning to