C template metaprogramming bookmark

Concepts, tools, and techniques from boost and beyond by david abrahams and aleksey gurtovoy. Therefore both the typename qualifier and subtype required to access the dependent name are managed by the alias. Although template metaprogramming and compiletime calculations does overlap, main purpose of the templates is to make generic functionclasses. One use of templates is for mathematical structures. Things like template, which look really weird but behave in an even more bizarre way. The word in the title refers to runtime metaprogramming, as opposed to compile time metaprogramming. Dec 10, 2014 template metaprogramming is much more fun than mere generic classes. The output of these templates include compiletime constants, data structures, and complete functions. It provides the foundation youll need to use the template metaprogramming effectively in your own work. For instance, consider compiletime regex matcher using constexpr. In mathematics, the factorial of a nonnegative integer n, denoted by n.

Metaprogramming with templates yes, the code checks whether the number is a prime number template struct isprime2. If you are into functional programming several other options are also available. The book deals with language aspects, design patterns, examples and applications seen as case studies. Being late to the metaprogramming party, i make no claim of having invented the techniques in this article. Here, we apply template metaprogramming to implement a generic rungekutta scheme that can be used to numerically solve ordinary differential equations. By angelika langer and klaus kreft, march 01, 2003. This post starts a series of articles following the contrived and tortuous path down insanity lane. In this article, well take up the metaprogramming thread and give you some.

The use of templates can be thought of as compiletime execution. In theory, any computable problem can be solved at compile time without ever executing compiled code. On the other hand it might result in code bloat and performance decrease. This document was created by an unregistered chmmagic, please. It can, for the most part, be considered to be programming with types in that, largely, the. C style arrays but, what if we want to return an array with 5 elements. Generic versus generative generic programming focuses on representing families of domain concepts parameterization generative programming also includes the process of creating concrete instances of concepts metaprogramming in generative programming, the principles of. For h omework, try s olving the hanoi tower problem by using template metaprogramming. The capabilities of the template alias allow us to clearly specify beforehand that we mean a type. Similarly, metaprogramming is writing programs about programs. What are some advanced uses of template metaprogramming in. It seems really cool, make the compiler do most of the work. For h omework, try s olving the hanoi tower problem by.

Template metaprogramming map metainformation metafunctions membre traits traits classes traits templates lists and trees as nested templates computing numbers fibonacci control structures computing types if,switch, while,do,for computing code ewhile,edo, efor expression templates 15. This book explains what metaprogramming is and how it is best used. It might even make sense to implement in python first and throw it away to pin down your flow and architecture. Template metaprogramming is generally not used in practical programs, it. There have been some articles dealing with template metaprogramming before over here. Now expanding about the use of templates for that purpose. Template metaprogramming is in fact turingcomplete, meaning that any computation expressible by a computer program can be computed, in some form, by a template metaprogram. Another advantage is that you can look at a template class and immediately see if it is a template metaprogram or an ordinary template class. A component of an academic program, normally of one term semester in duration, with a specific credit value. Then through template argument deduction the values of the sequence will be unpacked into the parameter ns. This greatly simplifies code when there are many template types to deal with. Template metaprogramming is a generic programming technique that uses extremely early binding. I was motivated to write this after i read eric nieblers thoughtprovoking tiny metaprogramming library article. Note that the second parameter is an int, not a type.

Grab it directly from the iterator c deref, parent, visitcount grab the first value from the subtree contained in the iterator c deref. C deref this specialization is only for leaf nodes. Efficient algorithms for membership testing, random access, and retrieval by key. While i consider myself falling rather in the camp of the aficionados, ive met a lot more people that dont have a strong interest for it, or that even find it downright disgusting, than tmp enthusiasts. This document was created by an unregistered chmmagic. Template function can be executed at runtime and constexpr functions can be templated. Metaprogramming with templates or tmp, template metaprogramming is a huge topic that deserves a whole book for itself. Today, i write about template metaprogramming which is programming with types and not values. This is clever, cool, and in the right hands can even be useful. The book metaprogramming gpus with sh actually doesnt have anything to do with template metaprogramming. In recent issues of cuj, thomas becker explained some principles of template metaprogramming 1, 2.

I think ill bookmark this and read it or at least try to everytime i feel like ive written ugly code. I dont think even he expected it to turn out quite the way he did, although i doubt hed complain about it now. Template metaprogramming is a great technique when used correctly. Template metaprogramming is both a curiosity and a powerful optimisation method. I read the book and even dabbled at template metaprogramming in the neverfinished version 2. Template parameters can be types int including enum, short, char, bool etc.

With variadic templates, parameter packs and template aliases. Jun 10, 20 this feature is not available right now. An introduction to metaprogramming for scientific computing dr conrad sanderson senior research scientist version 1. Template metaprogramming is generally not used in practical programs, it is an interesting conecpt though.