Functional Programming with C++ Template Metaprograms
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Functional Languages
Functional Programming Languages (FPL) 1. Definitions................................................................... 2 2. Applications ................................................................ 2 3. Examples..................................................................... 3 4. FPL Characteristics:.................................................... 3 5. Lambda calculus (LC)................................................. 4 6. Functions in FPLs ....................................................... 7 7. Modern functional languages...................................... 9 8. Scheme overview...................................................... 11 8.1. Get your own Scheme from MIT...................... 11 8.2. General overview.............................................. 11 8.3. Data Typing ...................................................... 12 8.4. Comments ......................................................... 12 8.5. Recursion Instead of Iteration........................... 13 8.6. Evaluation ......................................................... 14 8.7. Storing and using Scheme code ........................ 14 8.8. Variables ........................................................... 15 8.9. Data types.......................................................... 16 8.10. Arithmetic functions ......................................... 17 8.11. Selection functions............................................ 18 8.12. Iteration............................................................. 23 8.13. Defining functions ........................................... -
The Machine That Builds Itself: How the Strengths of Lisp Family
Khomtchouk et al. OPINION NOTE The Machine that Builds Itself: How the Strengths of Lisp Family Languages Facilitate Building Complex and Flexible Bioinformatic Models Bohdan B. Khomtchouk1*, Edmund Weitz2 and Claes Wahlestedt1 *Correspondence: [email protected] Abstract 1Center for Therapeutic Innovation and Department of We address the need for expanding the presence of the Lisp family of Psychiatry and Behavioral programming languages in bioinformatics and computational biology research. Sciences, University of Miami Languages of this family, like Common Lisp, Scheme, or Clojure, facilitate the Miller School of Medicine, 1120 NW 14th ST, Miami, FL, USA creation of powerful and flexible software models that are required for complex 33136 and rapidly evolving domains like biology. We will point out several important key Full list of author information is features that distinguish languages of the Lisp family from other programming available at the end of the article languages and we will explain how these features can aid researchers in becoming more productive and creating better code. We will also show how these features make these languages ideal tools for artificial intelligence and machine learning applications. We will specifically stress the advantages of domain-specific languages (DSL): languages which are specialized to a particular area and thus not only facilitate easier research problem formulation, but also aid in the establishment of standards and best programming practices as applied to the specific research field at hand. DSLs are particularly easy to build in Common Lisp, the most comprehensive Lisp dialect, which is commonly referred to as the “programmable programming language.” We are convinced that Lisp grants programmers unprecedented power to build increasingly sophisticated artificial intelligence systems that may ultimately transform machine learning and AI research in bioinformatics and computational biology. -
Functional Programming Laboratory 1 Programming Paradigms
Intro 1 Functional Programming Laboratory C. Beeri 1 Programming Paradigms A programming paradigm is an approach to programming: what is a program, how are programs designed and written, and how are the goals of programs achieved by their execution. A paradigm is an idea in pure form; it is realized in a language by a set of constructs and by methodologies for using them. Languages sometimes combine several paradigms. The notion of paradigm provides a useful guide to understanding programming languages. The imperative paradigm underlies languages such as Pascal and C. The object-oriented paradigm is embodied in Smalltalk, C++ and Java. These are probably the paradigms known to the students taking this lab. We introduce functional programming by comparing it to them. 1.1 Imperative and object-oriented programming Imperative programming is based on a simple construct: A cell is a container of data, whose contents can be changed. A cell is an abstraction of a memory location. It can store data, such as integers or real numbers, or addresses of other cells. The abstraction hides the size bounds that apply to real memory, as well as the physical address space details. The variables of Pascal and C denote cells. The programming construct that allows to change the contents of a cell is assignment. In the imperative paradigm a program has, at each point of its execution, a state represented by a collection of cells and their contents. This state changes as the program executes; assignment statements change the contents of cells, other statements create and destroy cells. Yet others, such as conditional and loop statements allow the programmer to direct the control flow of the program. -
Functional and Imperative Object-Oriented Programming in Theory and Practice
Uppsala universitet Inst. för informatik och media Functional and Imperative Object-Oriented Programming in Theory and Practice A Study of Online Discussions in the Programming Community Per Jernlund & Martin Stenberg Kurs: Examensarbete Nivå: C Termin: VT-19 Datum: 14-06-2019 Abstract Functional programming (FP) has progressively become more prevalent and techniques from the FP paradigm has been implemented in many different Imperative object-oriented programming (OOP) languages. However, there is no indication that OOP is going out of style. Nevertheless the increased popularity in FP has sparked new discussions across the Internet between the FP and OOP communities regarding a multitude of related aspects. These discussions could provide insights into the questions and challenges faced by programmers today. This thesis investigates these online discussions in a small and contemporary scale in order to identify the most discussed aspect of FP and OOP. Once identified the statements and claims made by various discussion participants were selected and compared to literature relating to the aspects and the theory behind the paradigms in order to determine whether there was any discrepancies between practitioners and theory. It was done in order to investigate whether the practitioners had different ideas in the form of best practices that could influence theories. The most discussed aspect within FP and OOP was immutability and state relating primarily to the aspects of concurrency and performance. This thesis presents a selection of representative quotes that illustrate the different points of view held by groups in the community and then addresses those claims by investigating what is said in literature. -
Functional Javascript
www.it-ebooks.info www.it-ebooks.info Functional JavaScript Michael Fogus www.it-ebooks.info Functional JavaScript by Michael Fogus Copyright © 2013 Michael Fogus. All rights reserved. Printed in the United States of America. Published by O’Reilly Media, Inc., 1005 Gravenstein Highway North, Sebastopol, CA 95472. O’Reilly books may be purchased for educational, business, or sales promotional use. Online editions are also available for most titles (http://my.safaribooksonline.com). For more information, contact our corporate/ institutional sales department: 800-998-9938 or [email protected]. Editor: Mary Treseler Indexer: Judith McConville Production Editor: Melanie Yarbrough Cover Designer: Karen Montgomery Copyeditor: Jasmine Kwityn Interior Designer: David Futato Proofreader: Jilly Gagnon Illustrator: Robert Romano May 2013: First Edition Revision History for the First Edition: 2013-05-24: First release See http://oreilly.com/catalog/errata.csp?isbn=9781449360726 for release details. Nutshell Handbook, the Nutshell Handbook logo, and the O’Reilly logo are registered trademarks of O’Reilly Media, Inc. Functional JavaScript, the image of an eider duck, and related trade dress are trademarks of O’Reilly Media, Inc. Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and O’Reilly Media, Inc., was aware of a trade‐ mark claim, the designations have been printed in caps or initial caps. While every precaution has been taken in the preparation of this book, the publisher and author assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. -
Functional Programming Lecture 1: Introduction
Functional Programming Lecture 13: FP in the Real World Viliam Lisý Artificial Intelligence Center Department of Computer Science FEE, Czech Technical University in Prague [email protected] 1 Mixed paradigm languages Functional programming is great easy parallelism and concurrency referential transparency, encapsulation compact declarative code Imperative programming is great more convenient I/O better performance in certain tasks There is no reason not to combine paradigms 2 3 Source: Wikipedia 4 Scala Quite popular with industry Multi-paradigm language • simple parallelism/concurrency • able to build enterprise solutions Runs on JVM 5 Scala vs. Haskell • Adam Szlachta's slides 6 Is Java 8 a Functional Language? Based on: https://jlordiales.me/2014/11/01/overview-java-8/ Functional language first class functions higher order functions pure functions (referential transparency) recursion closures currying and partial application 7 First class functions Previously, you could pass only classes in Java File[] directories = new File(".").listFiles(new FileFilter() { @Override public boolean accept(File pathname) { return pathname.isDirectory(); } }); Java 8 has the concept of method reference File[] directories = new File(".").listFiles(File::isDirectory); 8 Lambdas Sometimes we want a single-purpose function File[] csvFiles = new File(".").listFiles(new FileFilter() { @Override public boolean accept(File pathname) { return pathname.getAbsolutePath().endsWith("csv"); } }); Java 8 has lambda functions for that File[] csvFiles = new File(".") -
Notes on Functional Programming with Haskell
Notes on Functional Programming with Haskell H. Conrad Cunningham [email protected] Multiparadigm Software Architecture Group Department of Computer and Information Science University of Mississippi 201 Weir Hall University, Mississippi 38677 USA Fall Semester 2014 Copyright c 1994, 1995, 1997, 2003, 2007, 2010, 2014 by H. Conrad Cunningham Permission to copy and use this document for educational or research purposes of a non-commercial nature is hereby granted provided that this copyright notice is retained on all copies. All other rights are reserved by the author. H. Conrad Cunningham, D.Sc. Professor and Chair Department of Computer and Information Science University of Mississippi 201 Weir Hall University, Mississippi 38677 USA [email protected] PREFACE TO 1995 EDITION I wrote this set of lecture notes for use in the course Functional Programming (CSCI 555) that I teach in the Department of Computer and Information Science at the Uni- versity of Mississippi. The course is open to advanced undergraduates and beginning graduate students. The first version of these notes were written as a part of my preparation for the fall semester 1993 offering of the course. This version reflects some restructuring and revision done for the fall 1994 offering of the course|or after completion of the class. For these classes, I used the following resources: Textbook { Richard Bird and Philip Wadler. Introduction to Functional Program- ming, Prentice Hall International, 1988 [2]. These notes more or less cover the material from chapters 1 through 6 plus selected material from chapters 7 through 9. Software { Gofer interpreter version 2.30 (2.28 in 1993) written by Mark P. -
C++ Metastring Library and Its Applications⋆
C++ Metastring Library and its Applications! Zal´anSz˝ugyi, Abel´ Sinkovics, Norbert Pataki, and Zolt´anPorkol´ab Department of Programming Languages and Compilers, E¨otv¨osLor´andUniversity P´azm´any P´eter s´et´any 1/C H-1117 Budapest, Hungary {lupin, abel, patakino, gsd}@elte.hu Abstract. C++ template metaprogramming is an emerging direction of generative programming: with proper template definitions wecanenforce the C++ compiler to execute algorithms at compilation time. Template metaprograms have become essential part of today’s C++ programs of industrial size; they provide code adoptions, various optimizations, DSL embedding, etc. Besides the compilation time algorithms, template metaprogram data-structures are particularly important. From simple typelists to more advanced STL-like data types there are a variety of such constructs. Interesting enough, until recently string, as one of the most widely used data type of programming, has not been supported. Al- though, boost::mpl::string is an advance in this area, it still lacks the most fundamental string operations. In this paper, we analysed the pos- sibilities of handling string objects at compilation time with a metastring library. We created a C++ template metaprogram library that provides the common string operations, like creating sub-strings, concatenation, replace, and similar. To provide real-life use-cases we implemented two applications on top of our Metastring library. One use case utilizes com- pilation time inspection of input in the domain of pattern matching al- gorithms, thus we are able to select the more optimal search method at compilation time. The other use-case implements safePrint, a type-safe version of printf –awidelyinvestigatedproblem.Wepresentboththe performance improvements and extended functionality we haveachieved in the applications of our Metastring library. -
13 Templates-Generics.Pdf
CS 242 2012 Generic programming in OO Languages Reading Text: Sections 9.4.1 and 9.4.3 J Koskinen, Metaprogramming in C++, Sections 2 – 5 Gilad Bracha, Generics in the Java Programming Language Questions • If subtyping and inheritance are so great, why do we need type parameterization in object- oriented languages? • The great polymorphism debate – Subtype polymorphism • Apply f(Object x) to any y : C <: Object – Parametric polymorphism • Apply generic <T> f(T x) to any y : C Do these serve similar or different purposes? Outline • C++ Templates – Polymorphism vs Overloading – C++ Template specialization – Example: Standard Template Library (STL) – C++ Template metaprogramming • Java Generics – Subtyping versus generics – Static type checking for generics – Implementation of Java generics Polymorphism vs Overloading • Parametric polymorphism – Single algorithm may be given many types – Type variable may be replaced by any type – f :: tt => f :: IntInt, f :: BoolBool, ... • Overloading – A single symbol may refer to more than one algorithm – Each algorithm may have different type – Choice of algorithm determined by type context – Types of symbol may be arbitrarily different – + has types int*intint, real*realreal, ... Polymorphism: Haskell vs C++ • Haskell polymorphic function – Declarations (generally) require no type information – Type inference uses type variables – Type inference substitutes for variables as needed to instantiate polymorphic code • C++ function template – Programmer declares argument, result types of fctns – Programmers -
Purely Functional Data Structures
Purely Functional Data Structures Chris Okasaki September 1996 CMU-CS-96-177 School of Computer Science Carnegie Mellon University Pittsburgh, PA 15213 Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy. Thesis Committee: Peter Lee, Chair Robert Harper Daniel Sleator Robert Tarjan, Princeton University Copyright c 1996 Chris Okasaki This research was sponsored by the Advanced Research Projects Agency (ARPA) under Contract No. F19628- 95-C-0050. The views and conclusions contained in this document are those of the author and should not be interpreted as representing the official policies, either expressed or implied, of ARPA or the U.S. Government. Keywords: functional programming, data structures, lazy evaluation, amortization For Maria Abstract When a C programmer needs an efficient data structure for a particular prob- lem, he or she can often simply look one up in any of a number of good text- books or handbooks. Unfortunately, programmers in functional languages such as Standard ML or Haskell do not have this luxury. Although some data struc- tures designed for imperative languages such as C can be quite easily adapted to a functional setting, most cannot, usually because they depend in crucial ways on as- signments, which are disallowed, or at least discouraged, in functional languages. To address this imbalance, we describe several techniques for designing functional data structures, and numerous original data structures based on these techniques, including multiple variations of lists, queues, double-ended queues, and heaps, many supporting more exotic features such as random access or efficient catena- tion. In addition, we expose the fundamental role of lazy evaluation in amortized functional data structures. -
A Tool for the Evaluation of the Complexity of Programs Using C++ Templates
COMPUTATION TOOLS 2011 : The Second International Conference on Computational Logics, Algebras, Programming, Tools, and Benchmarking A Tool for the Evaluation of the Complexity of Programs Using C++ Templates Nicola Corriero, Emanuele Covino and Giovanni Pani Dipartimento di Informatica Università di Bari Italy Email: (corriero|covino|pani)@di.uniba.it Abstract—We investigate the relationship between C++ tem- template <int X> class pow<0,X> plate metaprogramming and computational complexity, show- {public: enum {result=1};}; ing how templates characterize the class of polynomial-time computable functions, by means of template recursion and specialization. Hence, standard C++ compilers can be used as The command line int z=pow<3,5>::result, produces at a tool to certify polytime-bounded programs. compile time the value 125, since the operator A::B refers to Keywords-Partial evaluation; C++ template metaprogram- the symbol B in the scope of A; when reading the command ming; polynomial-time programs. pow<3,5>::result, the compiler triggers recursively the template for the values <2,5>, <1,5>, until it eventually I. INTRODUCTION hits <0,5>. This final case is handled by the partially According to [7], template metaprograms consist of specialized template pow<0,X>, that returns 1. Instructions classes of templates operating on numbers and types as like enum{result = function<args>::result;} represent the a data. Algorithms are expressed using template recursion step of the recursive evaluation of function, and produce the as a looping construct and template specialization as a intermediate values. This computation happens at compile conditional construct. Template recursion involves the use time, since enumeration values are not l-values, and when of class templates in the construction of its own member one pass them to the recursive call of a template, no static type or member constant. -
Functional Programming at Work in Object-Oriented Programming
Functional Programming at Work in Object-Oriented Programming Narbel version 2010 Narbel Functional Programming at Work in Object-Oriented Programming 1 A Claim about Programming Styles Claim: Adding functional programming capabilities to an object-oriented language leads to benefits in object-oriented programming design. Narbel Functional Programming at Work in Object-Oriented Programming 2 Existing Languages with a FP-OOP Mix Some old and less old languages with FP+OOP: For instance, Smalltalk, Common Lisp (CLOS). More recently, Python or Ruby. Notations: FP, Functional programming; OOP, Object-oriented programming, Narbel Functional Programming at Work in Object-Oriented Programming 3 FP techniques emulated in OOP Practices in OOP languages include emulations of FP techniques: C++ programmers: function pointers and overloadings of the () operator, i.e. “object-functions” or functors. Java programmers: anonymous classes and introspection/reflexion. Narbel Functional Programming at Work in Object-Oriented Programming 4 Existence of FP-OOP Comparison Points The idea of using FP to enrich OOP is old, see e.g. the discussions about the problem of the user-defined datatype extension: User-defined types and procedural data structures as complementary approaches to data abstraction. Reynolds. 1975. The Expression Problem. Wadler. 1998. Narbel Functional Programming at Work in Object-Oriented Programming 5 A Trend: FP Extensions for OO Languages A recent trend: to propose and include typed FP extensions in mainstream static OO languages. Extensions for C++ (see e.g. Laufer, Striegnitz, McNamara, Smaragdakis), and work in progress in the C++ standard committees. Java 7 expected to include FP constructs. C# offers FP constructs (even more in its 3.0 version).