Thomas Mailund
Metaprogramming in R
Advanced Statistical Programming for Data Science, Analysis and Finance
Thomas Mailund
Aarhus N, Denmark
Any source code or other supplementary material referenced by the author in this book is available to readers on GitHub via the book's product page, located at www.apress.com/9781484228807 . For more detailed information, please visit www.apress.com/source-code .
ISBN 978-1-4842-2880-7
e-ISBN 978-1-4842-2881-4
DOI 10.1007/978-1-4842-2881-4
Library of Congress Control Number: 2017943347
© Thomas Mailund 2017
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Printed on acid-free paper
Introduction
Welcome to Metaprogramming in R . I am writing this book, and my books on R programming in general, to help make more advanced teaching material available beyond the typical introductory level most textbooks on R have. This book covers some of the more advanced techniques used in R programming such as fully exploiting functional programming, writing metaprograms (code for actually manipulating the language structures), and writing domain-specific languages to embed in R.
This book introduces metaprogramming. Metaprogramming is when you write programs that manipulate other programs; in other words, you treat code as data that you can generate, analyze, or modify. R is a very high-level language where all operations are functions, and all functions are data that you can manipulate.
There is great flexibility in how function calls and expressions are evaluated. The lazy evaluation semantics of R mean that arguments to functions are passed as unevaluated expressions, and these expressions can be modified before they are evaluated, or they can be evaluated in other environments than the context where a function is defined. This can be exploited to create small domain-specific languages and is a fundamental component in the “tidy verse” in packages such as dplyr or ggplot2 where expressions are evaluated in contexts defined by data frames.
There is some danger in modifying how the language evaluates function calls and expressions, of course. It makes it harder to reason about code. On the other hand, adding small embedded languages for dealing with everyday programming tasks adds expressiveness to the language that far outweighs the risks of programming confusion, as long as such metaprogramming is used sparingly and in well-understood (and well-documented) frameworks.
In this book, you will learn how to manipulate functions and expressions and how to evaluate expressions in nonstandard ways. Prerequisites for reading this book are familiarity with functional programming, at least familiarity with higher-order functions, that is, functions that take other functions as an input or that return functions.
Contents
- Chapter 1: Anatomy of a Function
- Chapter 2: Inside a Function Call
- Chapter 3: Expressions and Environments
- Chapter 4: Manipulating Expressions
- Chapter 5: Working with Substitutions
- Afterword
- Index
Contents at a Glance
- About the Author
- About the Technical Reviewer
- Introduction
- Chapter 1: Anatomy of a Function
- Chapter 2: Inside a Function Call
- Chapter 3: Expressions and Environments
- Chapter 4: Manipulating Expressions
- Chapter 5: Working with Substitutions
- Afterword
- Index
About the Author and About the Technical Reviewer
About the Author
Thomas Mailund
is an associate professor in bioinformatics at Aarhus University, Denmark. His background is in math and computer science, but for the last decade his main focus has been on genetics and evolutionary studies, particularly comparative genomics, speciation, and gene flow between emerging species.
About the Technical Reviewer
Massimo Nardone
has more than 22 years of experience in security, web/mobile development, the cloud, and IT architecture. His true IT passions are security and Android.
He has been programming and teaching how to program with Android, Perl, PHP, Java, VB, Python, C/C++, and MySQL for more than 20 years.
He holds a master of science degree in computing science from the University of Salerno, Italy.
He has worked as a project manager, software engineer, research engineer, chief security architect, information security manager, PCI/SCADA auditor, and senior lead IT security/cloud/SCADA architect for many years.
He currently works as a chief information security officer (CISO) for Cargotec Oyj.
He was a visiting lecturer and supervisor for exercises at the Networking Laboratory of the Helsinki University of Technology (Aalto University), and he holds four international patents (PKI, SIP, SAML, and proxy areas).
Massimo has reviewed more than 40 IT books for different publishing companies, and he is the coauthor of Pro Android Games (Apress, 2015).