Functional Programming In Haskell.pdf

FUNCTIONAL PROGRAMMING IN HASKELL*

TUTORIAL PRESENTATION

Fritz Ruehr Willamette University Salem, OR 97301 (503) 370-6165 [email protected]

ABSTRACT This tutorial will focus on functional programming in Haskell, a very high-level language which provides a unique "bird's-eye view" on many programming problems. Like other modern functional languages, Haskell derives its power from higher-order functions, parametric polymorphismand pattern-matching over algebraic data types. Popular Haskell implementations offer an interactive evaluationenvironment whichprovides immediate feedback on programming ideas, thus encouraging experimentation. But Haskell also offers the security of strong, static typing and the flexibility of polymorphism, a combination which helps forestall programming errors without a heavy syntactic overhead. In fact, Haskell's sparse syntax has been specifically designed to be reminiscent of mathematical notation and thus will be familiar to most people. Finally, Haskell features a "pure" mathematical semantics which supports equational reasoning, thus simplifying and streamlining the process of program development. Haskell has considerable local relevance in the Pacific Northwest due to the number of groups situated here which are involved in its definition, use and dissemination. These include the Pacific Software Research Center at the Oregon Graduate Institute (doing research on language implementation and semantics); Intel Corporation (using Haskell and related systems for hardware modeling and verification); the Galois Connections company (using Haskell for

________________________ * Copyright © 2001 by the Consortium for Computing in Small Colleges. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the CCSC copyright notice and the title of the publication and its date appear, and notice is given that copying is by permission of the Consortium for Computing in Small Colleges. To copy otherwise, or to republish, requires a fee and/or specific permission.

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JCSC 17, 2 (December 2001)

industrial applications, including cryptography); and Microsoft Research (using Haskell for graphics programming and as a source for network implementations under .NET). A quick introduction to syntax and language features will be provided through a series of short, interactive examples. This will be followed by an overview of a few medium-sized programs illustrating traditionalapplications in data structures, language implementation, graphics and web programming. A number of larger Haskell projects currently undergoing development in the region will also be showcased. Finally, the value of Haskell for Computer Science education will be discussed.

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