In accordance, the rules are mostly about don ts and provide not much content. I give an introduction to template metaprogramming, show how the typetraits library allows you the use template metaprogramming in a well structured and a portable way, and how you can use constexpr functions to replace template metaprogramming magic with ordinary functions. This post starts a series of articles following the contrived and tortuous path down insanity lane. These utilities are in the boostmpl namespace, which are referred to as mpl, omitting boost to make code examples more compact. Monkey patching is an object oriented programming technique that allows developers to. The other great thing about using this library, mpl, is that where you would write repeticious template code for every parameter in a template d library like tuples, you can automate with it with mpl. Its freely distributable, and published under the terms of the gnu general public license. And inspiring introduction to template metaprogramming. The two newer standards are not used in the code so that the examples can be rich, illustrate the continue reading.
Dissecting template metaprogramming in the standard library. A quasiquote mechanism is built on top of the monadic library. Efficient algorithms for membership testing, random access, and retrieval by key. Net is designed to help readers understand the basic concepts, advantages and potential pitfalls of metaprogramming. There have been some articles dealing with template metaprogramming before over here. Template metaprogramming is generally not used in practical programs, it is an interesting conecpt though. All of the code in the presentation is in this repository. An inspiring introduction into template meta programming. When we write code it usually looks the same for many different functions. Learn why metaprogramming is necessary and look at some of the components of metaprogramming textual macro languages, specialized code generators. Being late to the metaprogramming party, i make no claim of having invented the techniques in this article. This document was created by an unregistered chmmagic. Metaprogramming is a programming technique in which computer programs have the ability to treat other programs as their data.
It means that a program can be designed to read, generate, analyze or transform other programs, and even modify itself while running. This allows computations to be performed once at compile time rather than at each run time. The rst article on template metaprogramming 7 was published in 1995. I like to call this a meta metatemplate since the operation is defined in a class outside the template itself. May 01, 2017 introduction to template meta programming 1 may 2017. Starting off the list for examples of metaprogramming is monkey patching. Mos 4465a is an advanced financial ac modern advanced accounting in canada, 8th edition, mcgraw. The book deals with language aspects, design patterns, examples and applications seen as case studies. However, it will be used to generate complete functions. Using meta metatemplates it is possible to define a generic template for a special kind of operation, like an if or forstatement. The introduction to template metaprogramming in the guidelines ends uniquely. Metaprogram results are then compiled and merged into object code, including any backend optimization.
Meta programming template metaprogramming for haskell 8th edition meta mercado meta metahor definition compare epistemology and metaethics pdf handbook of metaanalysis in ecology and evolution meta products. This document was created by an unregistered chmmagic, please. Concepts, tools, and techniques from boost and beyond pdf,, download ebookee alternative note. The avr the avr 8bit microcontrollers modified harvard architecture was introduced in 1997. Oct 20, 2005 one of the most underused programming techniques is writing programs that generate programs or program parts. Lipari scuola superiore santanna template metaprogramming april 6, 2011 2 41. Even if this might be useful it can make the code very hard to understand in complex cases. Building the internet of things metaanalysis a structural equation modeling approach hepatitis viruses in ethiopia. Use template metaprogramming primarily to emulate concepts. Use template metaprogramming only when you really need to. Concepts, tools, and techniques from boost and beyond pdf, epub, docx and torrent then this site is not for you.
Template metaprogramming tmp is a metaprogramming technique in which templates are used by a compiler to generate temporary source code, which is merged by the compiler with the rest of the source code and then compiled. The reverse would be unreasonably hard but not technically impossible. Concepts, tools, and techniques from boost and beyond pdf, epub, docx and. Pdf c template metaprogramming download full pdf book. Template metaprograms have no mutable variables that is, no variable can change value once it has been initialized, therefore template metaprogramming can be seen as a form of functional programming. A metaprogram is executed as the result of template instantiation therefore, before compiled code is produced. The problems were solved by the traits template idiom see 3. Usually we limit the use of macros to the c programming language, and try to use them sparingly. These atmel microcontrollers are popular among a reasonably large number of developers because they provide decent performance coupled with low power consumption. The main problem is in name lookups, and the compiler could generate unique names during template instantiations. This is very obvious if we write an algorithm to sort a list of data, depending upon the data type we would need a different implementation of essentially the same thing. Pdf template metaprogramming is an emerging new direction of generative programming.
The techniques of tmp allow you to introduce compiletime computation to improve your programs and. The use of templates can be thought of as compiletime execution. The capabilities of the template alias allow us to clearly specify beforehand that we mean a type. This is because variables are all immutable, and hence it is necessary to use recursion rather than iteration to process elements of a set. 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. Therefore both the typename qualifier and subtype required to access the dependent name are managed by the alias. When you find yourself in need of partially specializing a function template beware, this does not mean that in this case you are in need, as dyps answer shows, you may either resort to overloading see the last update at the end of this answer or, if thats not possible, wrap that function template into a class template, and have a static, non template member function replace your. The craft of writing useful, maintainable, and extensible source code which can be interpreted or compiled by a. 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.
Generally, constexprbased solutions are simpler, and promise to get much easier with future versions of the language. Template meta programming works only for single argument template classes. Template haskell extends the metalevel operations of static scoping and static typechecking into the objectlevel code fragments built using its quasiquote mechanism sections 9 and 7. Multi dimensional arrays using template meta programming.
It introduces core concepts in clear, easytofollow language and then it takes you on a deep dive into the tools and techniques youll use to implement them in your. Metaprogramming or more specifically, template metaprogramming is the practice of using templates to create constants, functions, or data structures at compiletime. The syntax and techniques needed are pretty horrendous. One of the most common examples of using static code i. An introduction to metaprogramming for scientific computing dr conrad sanderson senior research scientist version 1.
What i think your article misses that the more you use it. This greatly simplifies code when there are many template types to deal with. Adding a class template argument cannot be achieved directly. Yes, its a weird name, but its a powerful and dangerous tool. In general, macros are frowned upon in this role and templates are preferred, although they are not as. An outer class should be used to pass the template argument through. Things like template, which look really weird but behave in an even more bizarre way. Weve had the idea of writing about template metaprogramming for. Concepts, tools, and techniques from boost and beyond with cd 05 edition 9780321227256 by david abrahams and. A complete mpl reference manual, in html and pdf form. The output of these templates include compiletime constants, data structures, and complete functions. See how to build a code generator and get a closer look at languagesensitive macro programming in scheme. Advanced template use following a short overview of subtleties related to templates the main characteristics of template meta programming are introduced.
Mos 4465a is an advanced financial ac gold advanced maximiser with key. It can be quite cumbersome to write code in this way. A metaprogram is a program that generates or manipulates program code. In fact many template implementations implement flow control only through recursion, as seen in the example below. Lets cover variable templates first, because theyre a lot like class templates. The book is available in html, pdf, postscript, and plain text. I have played off an on with meta template programming for some years now.
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