Haskell Videos

We've kicked off C9 Lectures with a journey into the world of Functional Programming with functional language purist and high priest of the lambda calculus, Dr. Erik Meijer (you can thank Erik for many of the functional constructs that have shown up in languages like C# and VB.NET. When you use LINQ, thank Erik in addition to Anders). We will release a new chapter in this series every Thursday. In Chapter 10, Declaring Types and Classes, Dr. Meijer teaches us about type declarations, data declarations, arithmetic expressions, etc.  In Haskell, a new name for an existing type can be defined using a type declaration:  type String = [Char]  String is a synonym for the type [Char]. Like function definitions, type declarations can also have parameters. Type declarations can be nested, but not recursive. Nested: type Pos   = (Int,Int) type Trans = Pos -  Pos Illegal recursion: type Tree = (Int,[Tree]) A completely new type can be defined by specifying its values using a data declaration:  data Bool = False | True Bool is a new type, with two new values False and True. Get the presentation slides here Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9

We've kicked off C9 Lectures with a journey into the world of Functional Programming with functional language purist and high priest of the lambda calculus, Dr. Erik Meijer (you can thank Erik for many of the functional constructs that have shown up in languages like C# and VB.NET. When you use LINQ, thank Erik in addition to Anders). We will release a new chapter in this series every Thursday. In Chapter 9, Interactive Programs, Dr. Meijer will teach us how to make programs in Haskell that are side-effecting: interactive. Haskell programs are pure mathematical functions with no side effects. That said, you want to be able to write Haskell programs that can read input from the keyboard and write output to the screen which are in fact side effects. So, interactive programs have side effects... Interactive programs can be written in Haskell by using types to distinguish pure expressions from impure actions that may involve side effects. Consider the following: IO a The type of actions that return values of type a IO Char The type of actions that return a character IO() The type of purely side effecting actions that return no result value Warning: This lecture may contain the use of the term Monad. Do not fear. Everything will be OK. :) You should watch these in sequence (or skip around depending on your curent level of knowledge in this domain): Get the presentation slides here Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8

We've kicked off C9 Lectures with a journey into the world of Functional Programming with functional language purist and high priest of the lambda calculus, Dr. Erik Meijer (you can thank Erik for many of the functional constructs that have shown up in languages like C# and VB.NET. When you use LINQ, thank Erik in addition to Anders).  We will release a new chapter in this series every Thursday. In Chapter 8, Functional Parsers, it's all about parsing and parsers. A parser is a program that analyses a piece of text to determine its syntactic structure. In a functional language such as Haskell, parsers can naturally be viewed as functions.   type Parser = String - Tree A parser is a function that takes a string and returns some form of tree. You should watch these in sequence (or skip around depending on your curent level of knowledge in this domain): Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7

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We've kicked off C9 Lectures with a journey into the world of Functional Programming with functional language purist and high priest of the lambda calculus, Dr. Erik Meijer (you can thank Erik for many of the functional constructs that have shown up in languages like C# and VB.NET. When you use LINQ, thank Erik in addition to Anders).  We will release a new chapter in this series every Thursday. In Chapter 7, Dr. Meijer teaches us about Higher-Order Functions. A function is called higher-order if it takes a function as an argument and returns a function as a result: twice    :: (a - a) - a - a twice f x = f (f x) The function twice above is higher order because it takes a function (f x) as it first argument and returns a function (f(fx))  Dr. Meijer will elaborate on why higher-order functions are important and there are some really interesting side-effects of higher-order functions such as defining DSLs as collections of higher-order functions and using algebraic properties of higher-order functions to reason about programs. You should watch these in sequence (or skip around depending on your curent level of knowledge in this domain): Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Now, we do have a textbook and you should go buy it: The great Graham Hutton's Programming in Haskell. We worked with the publisher, Cambridge University Press, to get all Niners a 20% discount on the book. Now, you don't need the book to learn a great deal from this lecture series since Graham's website has all the slides and samples from the book as well as answers to the exercises. That said, it's highly recommended reading and you should consider it. The promotion code is 09HASK and it is vaild on both the Hardback: 9780521871723 and Paperback: 9780521692694. The catalog pages are: Hardback: http://www.cambridge.org/us/catalogue/catalogue.asp?isbn=9780521871723 and the paperback is: http://www.cambridge.org/us/catalogue/catalogue.asp?isbn=9780521692694 Note: This special offer is valid until December 31, 2009

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James Kalm partakes in the press preview for this icon of American Modernism.

Haskell is the world's leading purely functional programming language that offers a radical and elegant attack on the whole business of writing programs. In the last two or three years there has been an explosion of interest in Haskell, and it is now being used for a bewildering variety of applications. In this tutorial, I will try to show you why programming in Haskell is such fun, and how it makes you think about programming in a new way. I'm going to use xmonad (http://xmonad.org) as my running example; it's an X11 window manager written entirely in 500 lines of Haskell. Based on xmonad I will show you how to write functional programstest them using QuickCheckwrite imperative programscall foreign functionsuse Haskell for scripting applicationsI won't assume you know any functional programming at all, but I will assume that you are an experienced professional programmer, so I will move along quite briskly.From the O'Reilly Media Open Source Convention, July 23, 2007. Video provided by Galois. Slides are available here.

Part 2 of 2Haskell is the world's leading purely functional programming language that offers a radical and elegant attack on the whole business of writing programs. In the last two or three years there has been an explosion of interest in Haskell, and it is now being used for a bewildering variety of applications. In this tutorial, I will try to show you why programming in Haskell is such fun, and how it makes you think about programming in a new way. I'm going to use xmonad (http://xmonad.org) as my running example; it's an X11 window manager written entirely in 500 lines of Haskell. Based on xmonad I will show you how towrite functional programstest them using QuickCheckwrite imperative programscall foreign functionsuse Haskell for scripting applicationsI won't assume you know any functional programming at all, but I will assume that you are an experienced professional programmer, so I will move along quite briskly.From the O'Reilly Media Open Source Convention, July 23, 2007. Video provided by Galois. Slides are available here.