Better Software - November 2007 - (Page 12)

Code Craft Buddy, CanYou Paradigm? by Chuck Allison Lee Copeland, managing technical editor of Better Software magazine, recently wrote of the Whorfian Hypothesis, which, according to Wikipedia.org, “argues that the nature of a particular language influences the habitual thought of its speakers.” As early as 1957, Kenneth Iverson, inventor of APL, prefaced his presentation of that interesting language with the phrase “Language is a tool of thought.” His goal was to efficiently process large arrays of data in multiple dimensions, so APL sports numerous operators, all very succinct and mutually orthogonal. When it’s time to cut code, the programming language we’re using tends to govern our thoughts. A C programmer will conjure up appropriate functions; a Java programmer will see nothing but objects; a developer using Haskell will traffic in lists and higher-order functions. Each programming style, or paradigm, has its claim to fame, and one is not necessarily better than another. A message that needs to get out nowadays, both in industry and academia, is that object orientation is just another paradigm. It has its place and has certainly helped us write better-organized code for large projects, but it is not the One True Paradigm—because there isn’t one. So, should developers be proficient in multiple languages? Certainly, but it is even more important to master multiple paradigms, which is not necessarily the same thing: A language may or may not force a particular paradigm upon you. Java pretty much forces you to do objects, so you’ll hurt yourself if you use it to write simple procedural code or to program in the functional style, à la Lisp. Likewise, you can do objects in C, but you have to build up so much scaffolding to support it that you end up feeling like you’re rubbing a cat backward. However, languages like C++, Python, Ruby, D, and CLOS support multiple paradigms naturally. the imperative/OO world. Functional programming, first made accessible through Lisp, is another powerful programming paradigm that is older than you might think. Lisp wasn’t really usable until about 1960, but it is based on Alonzo Church’s lambda calculus, which came almost thirty years earlier, so the functional paradigm was fairly mature before it was realized on a computer. Functional languages treat functions like they treat built-in types—they can be passed and returned as values to and from other functions, and can even be created at runtime. Some very powerful constructs come to life this way. #A >>> >>> >>> [1, Python example nums = [1,2,3,4] morenums = [x+1 for x in range(4)] morenums 2, 3, 4] An Invitation to Functional Programming The most commonly used programming styles nowadays are imperative (aka, procedural), object oriented, and functional, but many others exist (e.g., declarative, logic, constraint). Imperative languages closely mirror computer internals—they implement instructions that change machine state. The objectoriented (OO) style of programming is mostly imperative programming extended with the ability to package data and related functionality as classes. Most programmers seem to live in 12 www.StickyMinds.com Listing 1 Since lists are so central in functional programming, you can easily create them by placing expressions inside brackets in Haskell and Python, as shown in listing 1. The definition of morenums illustrates a list comprehension, BETTER SOFTWARE NOVEMBER 2007 GETTY IMAGES http://www.StickyMinds.com

Table of Contents Feed for the Digital Edition of Better Software - November 2007

Better Software - November 2007 Contents MarkYour Calendar Technically Speaking What’s Happening @StickyMinds.com Code Craft Test Connection Management Chronicles The Measure of a Management System Behind the Scenes A Story About User Stories and Test-Driven Development Product Announcements The Last Word Ad Index

Better Software - November 2007

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