Net is designed to help readers understand the basic concepts, advantages and potential pitfalls of metaprogramming. An introduction to metaprogramming for scientific computing dr conrad sanderson senior research scientist version 1. Metaprogramming in commonlisp is about the metaobjectprotocol. This is a function that adds its two parameters and stores the result in the result enum member. With a metaprogramming api, precompiled shader programs could still be used in the traditional manner simply by. In this session, well break down what metaprogramming is and. The ability of a program to manipulate as data something representing the state of a program during its own execution. A metaprogram is a program that generates or manipulates program code. Contribute to akimboykometaprogramming development by creating an account on github. Caveat i decided to do this talk after getting thoroughly lost on the recent talk on sfinae. The c api known as vix is an api that lets customers write scripts and programs to manipulate virtual machines. Yes, its a weird name, but its a powerful and dangerous tool. Api transitionsusability componentspecific optimization all kinds of instrumentation.
Hana or boostmpl if you wish, can i build a list of types at compile time or static. Metaprogramming is a technique that consists in writing programs that treat other. So metaclasses create classes, and classes create instances. In some cases, this allows programmers to minimize the number of lines of code to express a solution hence reducing development time. The use of templates can be thought of as compiletime execution.
That doesnt work if the language doesnt support metaprogramming well. Typedirected metaprogramming in rust will crichton. Macros make metaprogramming possible and define the. Metaprogramming with templates yes, the code checks whether the number is a prime number template struct isprime2 static const int resisprime2 res.
Metaprogrammingits a term that may come across as abstract, nebulous, or just downright scary. Only a metaprogramming api provides a natural path for a code modification system. Recently, however, ive faced a problem that could not be solved by the means outlined in the article. This book avoids abstract theory and instead teaches you solid practices youll find useful immediately. In order to explain metaprogramming, let me explain a few basic concepts first. In this article, they attempt to make amends, by helping programmers eschew cleverness. Starting off the list for examples of metaprogramming is monkey patching. Metaprogramming in c is the art of creating new language constructs, typically using macros. You can call this at compile time with something like adder result, which will be expanded at compile time and act exactly like a literal 3 in your program branching. Developers can sign up with an api key to make calls that will display json responses in return. Developers can use json formats to parse responses and obtain urls of generated files.
The c api is designed for three kinds of customers. This makes it possible to create a template which calculates a value at return time, a value which can then be used as a constant in the rest of the program. In a small summary report written for the national institute of mental health, entitled programming and metaprogramming in the human biocomputer 19661967, lilly lends his unique insight after five years of research combining lsd25 and sensory deprivation to alter behavioral and cognitive patterns in. The introduction to template metaprogramming in the guidelines ends. Metaprogramming in the host language yacc is an example. Efficient algorithms for membership testing, random access, and retrieval by key. This article describes a technique for using the c preprocessor to implement a form of metaprogramming in c, allowing a programmer to define custom looping and control constructions which behave syntactically like c s own for, while and if. Therefore, i call this projecttechnique template metaprogramming programming. Programming and metaprogramming in the human biocomputer. If you are a rust metaprogramming compilerhacking fanatic like me, then the specifics will help you understand how to actually use the compilers api.
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. Sometimes it will be useful to get the dimensionality tensor. Learn why metaprogramming is necessary and look at some of the. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. After so many years and blog migrations, this article might be broken or outdated. Reflection support by means of template metaprogramming. Too much cleverness in programming makes designs more complicated, code more fragile, learning curves steeper, and worst of all, it makes debugging harder. What matters is that metaprogramming is about manipulating the code i wrote, using additional code i wrote, to produce the final code that executes. It introduces core concepts like code generation and application composition in clear, easytofollow language, and then it takes you on a deep dive.
Metaprogramming python 3 patterns, recipes and idioms. John c lilly, and thank you coincidence control publishing for releasing this edition unabridged, straight from johns biocomputer to yours. What weve done now is program a little function or subroutine that is evaluated compiletime, using tmp. Normally when we write a class, the default metaclass type is automatically invoked to create that class, and we arent even aware that its happening its possible to explicitly code the metaclass creation of a class. Unification of compiletime and runtime metaprogramming.
That is the subset of metaprogramming called generativeprogramming. An introduction to template metaprogramming barney dellar software team lead toshiba medical visualisation systems. Otherwise, you can treat this as an example of what typedirected metaprogramming could look like in a brighter future where these apis are stable. Template metaprogramming tmp is a metaprogramming technique in which templates are. Now expanding about the use of templates for that purpose.
Metaprogramming is the writing of computer programs that write or manipulate other programs or themselves as their data, or that do part of the work at compile time that would otherwise be done at runtime. Great introduction to c metaprogramming by simon tatham can be found here. Youll explore plenty of realworld examples that reinforce key concepts. Most people insist on trying to metaprogram from inside their favorite language. This is typical of cbased libraries, where parameters are. It means that a program can be designed to read, generate, analyze or transform other programs, and even modify itself while running. 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 goal is to offer a different perspective on metaprogramming, how we can approach it, and the kind of use cases it can address.
Michele and david feel, in part, responsible for some excesses of cleverness in python metaclasses. Being late to the metaprogramming party, i make no claim of having invented the techniques in this article. Jonathan cohen nvidia research gtc, san jose convention center, ca sept. Boost libraries discussed in this book that are not yet part of an official release. A collection of hopefully relevant links with some minimal explanations, which would allow the reader to see some examples and applications of metaprogramming in mathematica, or at least examples of what i consider metaprogramming in mathematica. A complete mpl reference manual, in html and pdf form. Another more recent library that shows it can be done in python is macropy. A conditional branch can be constructed by writing two alternative specialisations of a template class. A way around this is to do metaprogramming from outside the language, using program transformation tools. The only widely known example of metaprogramming in python was an implementation of a goto and comefrom keyword done as an aprilfools joke. Anything thats wrong is the fault of a blog migration, everything thats right is because the author of this article spent countless hours researching this topic. It is highlevel, easy to use, and practical for both scripters and application programmers. The book deals with language aspects, design patterns, examples and applications seen as case studies. Metaprogramming elixir write less code, get more done and have fun.
These functions can be used in both taichi kernels and python scripts. Metaprogramming is a programming technique in which computer programs have the ability to treat other programs as their data. The compiler can usefully do metaprogramming thats following metaprogramming directives i wrote at a variety of stages, early, middle, late. The output of these templates include compiletime constants, data structures, and complete functions. An example of this is an sqrt function that takes an integer i.
In smalltalk, it is about hacking doesnotunderstand. The biocomputer has stored program properties, and self. Monkey patching is an object oriented programming technique that allows developers to. Copyright c 20, decorators with args 47 from functools import wraps def debugprefix. While this approach lets us avoid a heavyweight library for building abstract syntax. Metaprogramming is frowned on in python and considered unpythonic.
Lilly, refers to the hardware of the human anatomy. One use of templates is for mathematical structures. I dont know who wrote the above, but i think it is wrong. This would include the brain, internal organs, and other human organ systems such as cardiovascular, digestive, endocrine, immune, integumentary, lymphatic, muscular, nervous, reproductive, respiratory, skeletal, and urinary systems.
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