The pattern allows you to produce different types and representations of an object using the same construction code. Its key characteristic is the focus on structural changes, strictly separated from changes in functionality. Refactoring is the process of changing a software system so the softwares structure and performance are improved without altering the functional behavior of the code. Refactoring is the process of improving the design of existing programs without changing their functionality. A treebased approach to support refactoring in multi. Refactoring is about improving the design of existing code and as such it must be familiar to every programmer, software engineer and designer. I showed an example of a problem that suits a functional approach and demonstrated turning several lines of imperative code with nested foreach loops and ifstatements into a single line of functional code. Citeseerx a case study in refactoring functional programs. I dont pretend to be an expert in functional programming, but i hope youll find interesting to have the different steps and thoughts that have guided me during this refactoring. Refactoring functional programs simon thompson and claus reinke computing laboratory, university of kent abstract refactoring is the process of redesigning existing code without changing its functionality.
Ppt tools for refactoring functional programs powerpoint presentation free to download id. Refactoring functional programs university of kent. Current research does not empirically answer the question, why and how do programmers refactor functional programs. Request pdf program refactoring using functional aspects a functional aspect is an aspect that has the semantics of a transformation. I recently posted a comparison of java, scala and clojure with regard to one specific refactoring problem. Jan 29, 2016 i dont pretend to be an expert in functional programming, but i hope youll find interesting to have the different steps and thoughts that have guided me during this refactoring.
Provides an interface for creating objects in a superclass, but allows subclasses to alter the type of objects that will be created. Yesterday, one of my colleagues asks me to help him to get the functional solution of a simple programming challenge. Before changing the functionality of a software system, it is often necessary to restructure. Refactoring functional programs micro refactoring as a part of program development. Scala is typesafe with somewhat clike syntax, though it really has as much syntax in common with haskell as with c. Pdf tool support for refactoring functional programs. Refactoring functional programs kent academic repository. Pdf a catalogue of functional refactorings version 1. These notes cover refactoring in functional languages, using haskell as the medium, and. We present the haskell refactorer, hare, and the erlang refactorer, wrangler, as examples of fullyfunctional refactoring tools for functional programming languages. Our paper centres on the case study of refactoring a 400 line haskell program written by one of our students. In advanced functional programming, volume 3622 of lecture notes in computer science, pages 3357. We briefly introduce the ideas behind refactoring, and a set of elementary functional refactorings.
It is the neglect of timely repair that makes rebuilding necessary. When writing programs with pure functions, it appears that there are some refactorings which are more common in this paradigm. The term refactoring specifically refers to a common activity in programming and software maintenance. Code refactoring is the process of changing a computer program s internal structure without modifying its external functional behavior or existing functionality, in order to improve internal nonfunctional properties of the software, for example to improve code readability, to simplify code structure, to change code to adhere to a given.
Often, refactoring precedes a program modification or extension, bringing the program into. Before changing the functionality of a software system, it is. A case study in refactoring functional programs extended abstract simon thompson 1. Improving the design of existing code shows how refactoring can make objectoriented code simpler and easier to maintain. Code refactoring is the process of restructuring existing computer codechanging the factoringwithout changing its external behavior. Refactorings differ from other sorts of program transformation in being applied to source code, rather than to a core language within a. How to refactor an oo program into a functional one. Refactoring is the process of redesigning existing code without changing its functionality. The course concludes with a refactoring kata that students can perform on their own to practice their refactoring skills. Refactoring to functional code tim ross software developer. Hare and wrangler can be downloaded respectively from. Our paper centres on the case study of refactoring a 400 line haskell program written by one of our. In order to answer the question, i conducted a case study on three open source projects in haskell.
Refactoring existing java code to use lambda expressions. Citeseerx tool support for refactoring functional programs. Ramda offers some common fp utilities to help you code in the fp style or just slowly convert parts of your codebase to the fp style. With more than 110 refactorings, refactor pro has more refactorings than any other tool for any platform. Refactoring legacy applications using functional aspects is just as. Ppt tools for refactoring functional programs powerpoint. We report on the experience of tool building, contrast the two tools, and these tools with their oo equivalents. This course covers when and how to refactor code, as well as a wide variety of code smells that may indicate some refactoring is warranted. Richard whately refactoring refactoring is the activity of improving the internal structure or operation of a code or component without changing its external behavior. Refactoring is to change to be easily maintainable, good readability and improve efficiency. A case study on refactoring in haskell programs proceedings. Functional refactoring in javascript software craftsman.
Program refactoring using functional aspects request pdf. Join this journey where well look at code we usually write when developing business applications and how to refactor this using functional paradigms. Hare and wrangler are designed to handle multimodule projects in complete languages. Our paper centres on the case study of refactoring a 400 line haskell. Citeseerx document details isaac councill, lee giles, pradeep teregowda. In this paper we explore the prospects for refactoring functional programs. Refactoring functional programs there is no one correct design. Tool support for refactoring functional programs citeseerx.
The adobe flash plugin is needed to view this content. You just have to have the guidance to lead you in the direction until you can do it yourself. In my previous post i explained that some problems are better suited to a functional approach than traditional, imperative code. Some of these relate to the well know catalog of refactorings introduced by martin fowler, but others are not on that list. I showed an example of a problem that suits a functional approach and demonstrated turning several lines of imperative. This presentation starts with multiple code examples written in imperative style. Refactoring are performed to improve the functional factorings of a software system in order to increase understand ability and modifiability. Refactoring is nonfunctional requirement when code perform correct functionality for which it is designed however difficult to debug, requires more effort to maintain and some performance bottleneck. Refactoring is a disciplined technique for restructuring an existing body of code, altering. The goal of software development is the continuous delivery of. Refactoring is a critical developer skill that helps keep code from collapsing under its own weight. Today refactoring requires considerable design knowhow, but once tools become available, all programmers should be able. Apr, 2010 in my previous post i explained that some problems are better suited to a functional approach than traditional, imperative code.
Refactoring tools for functional languages kent academic. Refactoring is the process of changing the design of a program without changing what it does. To download, cd to the latest snapshot of hare and type darcs get kent. In our project, we explore the prospects for refactoring functional programs, taking haskell as a concrete casestudy. Both are insightful interpretations of functional programming. Man y functional programs are small, but others, such as the glasgow haskell. The common nomenclature in functional programming is that you refactor programs using pure functions.
What is refactoring and what is only modifying code. What better way to learn that transition than taking imperative code and refactoring it to a more functional style. To download, cd to the latest snapshot of hare and type darcs get you will need darcs available here. Simon thompson shows the particularities of functional programming refactoring through examples in haskell and erlang, and discusses what lays ahead for fp refactoring in the next 10 years. Refactoring functional programs simon thompson and claus reinke technical report 1601, university of kent, computing laboratory, october 2001. Oct 02, 2017 what better way to learn that transition than taking imperative code and refactoring it to a more functional style.
Refactoring functional programs experience of building refactoring tools for haskell and erlang we have built tools for refactoring programs written in the functional languages haskell and erlang. Refactoring is used to improve system maintainability and extend its usable life span. The paper also explores the background to refactoring, provides a taxonomy for describing refactorings and draws some conclusions about refactoring for functional programs. Our project refactoring functional programs refactor fp, has developed the. We present the haskell refactorer, hare, and the erlang refactorer, wrangler, as examples of fully functional refactoring tools for functional programming languages. Refactoring is intended to improve the design, structure, andor implementation of the software its nonfunctional attributes, while preserving the functionality of the software. Refactoring has recently come to prominence in the oo community. Analysis of code refactoring impact on software quality. When a software system is successful, there is always a need to keep. Functional refactoring in javascript software craftsman medium. These notes cover refactoring in functional languages, using haskell as the medium, and introducing the hare tool for refactoring in haskell. Crossing the gap from imperative to functional programming. Most of the team is unfamiliar with fp, so rather than diving into massive rewrites to convert large chunks of code from objectoriented programming to fp, we. This paper discusses the variety of pragmatic and implementation issues raised by our work on the haskell refactorer.
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