home An invitation to FP for Clojure noobs I’ve heard newcomers to Clojure ask how to get started with functional programming. I believe that learning to program in the functional style is mostly a matter of practice. The newcomer needs to become familiar with a handful of higher order functions, and how they are used in common idioms. Here is what I propose. I have packaged the problems as a Leiningen project. What I recommend is deceptively simple. Here’s the important point: once you understand the solution, delete it and then reconstruct it. Here are a few things to avoid. Do not attempt to learn Clojure and new tooling, say Emacs+slime, at the same time. Don’t worry about parts of Clojure not immediately related to functional programming. The Project Euler problems do require a bit of math. Don’t worry about lambda calculus, type theory, category theory, monads, morphisms, or any such abstract concerns. When I first started learning Clojure, I did so by working Project Euler problems.
Learn Clojure Object Computing, Inc. - Java News Brief - March 2009 by R. Mark Volkmann, Partner Object Computing, Inc. (OCI) last updated on 6/2/13 Contents Introduction The goal of this article is to provide a fairly comprehensive introduction to the Clojure programming language. Please send feedback on errors and ways to improve explanations to email@example.com, or fork the repository and send a pull-request. You said X, but the correct thing to say is Y. Updates to this article that indicate the "last updated" date and provide a dated list of changes will be provided at Code examples in this article often show the return value of a function call or its output in a line comment (begins with a semicolon) followed by "->" and the result. (+ 1 2) ; showing return value -> 3 (println "Hello") ; return value is nil, showing output -> Hello Functional Programming Functional programming is a style of programming that emphasizes "first-class" functions that are "pure". In practice, applications need to have some side effects.
Clojure Scripting - ImageJ Check out clojure web site and particularly the chapter on Java interoperability. Clojure is not a scripting language: Clojure compiles directly to JVM bytecode, and thus runs at native speed. Thus one must think of Clojure as a true alternative to Java the language, but much more expressive, flexible and powerful. See also: Clojure Cookbook. Using Clojure inside Fiji Go to "Plugins - Scripting - Clojure Interpreter". See Scripting Help for details on keybindings and how to use the interpreter. ^ Ctrl+) will add all necessary ending parenthesis. A minimal, complete clojure example: To create scripts, just save them as .clj text files (with an underscore in the name) in any folder or subfolder of Fiji's plugins folder, and run "Plugins - Scripting - Refresh Clojure Scripts" to update the menus (it's done automatically at start up as well). To edit a script, just edit and save it with your favorite text editor. To execute a script, do any of: Select it from the plugins menus. The simplest is: 1.
Improving Clojure’s docs You are here: Home / Clojure / Improving Clojure’s docs There was an interesting conversation today on #clojure about various aspects of Clojure documentation. This is not a new topic I thought I’d goose it a little more publicly. There are docs in several places (this is incomplete, but most easily found): clojure.org – “official”, first-stop, very small editor set dev.clojure Confluence – wiki, editable by many but less formal. Clojure Docs – a place to stash per-function examples in core and libraries Learn-Clojure – a gathering of “learning” resources At last year’s conj, I was inspired to improve and talked Stu into letting me make some changes <evil-laugh/>. Eventually, my free time ran out and I declared doc change bankruptcy and just put my todo list on the dev site . If you come out of the conj inspired to do some doc work to improve your world, here are some suggestions: Pick up one of the items on the .org TODO list (or add your own pointy edge).
7 Rules for Writing Clojure Programs « Two Guys Arguing Over the past 5 months, I’ve had the incredible opportunity at Revelytix to write Clojure every day and get paid for it. 5 months is an incredibly short time to pretend to have learned anything, but I can feel the beginnings of a style emerge in my programming and while writing a small program some ideas congealed into actual words that I thought I’d capture here. Update: Ugh. I really messed up. As it has been noted in the comments below, on Hacker News and even Twitter, my final solution is much (much) slower thanks to it’s not one, but two sorts. In the end, the whole thing is doubly redundant as clojure.contrib.seq-utils implemented a function ‘frequencies’ which will be in 1.2′s clojure.core. #1 – Your brain will think in steps. The program that brought these ideas to life was a small utility I needed to read a file and print out the set of characters contained within along with the number of occurrences of each character. Rule #1 – Your brain will think in steps. "abcdaabccc"
relevance/labrepl SICP in Clojure functional-koans/clojure-koans Closure (computer science) def start(x): def increment(y): return x+y return increment The closures returned by start can be assigned to variables like first_inc and second_inc. Invoking increment through the closures returns the results below: first_inc = start(0) second_inc = start(8) first_inc(3) # returns 3 second_inc(3) # returns 11 # The x value remains the same for new calls to the function: first_inc(1) # returns 1 second_inc(2) # returns 10 In ML, local variables are allocated on a linear stack. When a closure is created, it copies the values of those variables that are needed by the closure into the closure's data structure. Closures are closely related to Actors in the Actor model of concurrent computation where the values in the function's lexical environment are called acquaintances. Closures are closely related to function objects; the transformation from the former to the latter is known as defunctionalization or lambda lifting. Closures have many uses:
Mark Volkmann's Clojure Page Mark Volkmann's Page This page contains resources related to the Clojure programming language. Article Change History Sounds Even Jennifer Aniston has quit using other programming languages and now prefers Clojure. Sound Clip #1 Sound Clip #2 Learning Clojure - What should I know about Java and more Learn clojure in Y Minutes Clojure is a Lisp family language developed for the Java Virtual Machine. It has a much stronger emphasis on pure functional programming than Common Lisp, but includes several STM utilities to handle state as it comes up. This combination allows it to handle concurrent processing very simply, and often automatically. (You need a version of Clojure 1.2 or newer) Further Reading This is far from exhaustive, but hopefully it’s enough to get you on your feet. Clojure.org has lots of articles: Clojuredocs.org has documentation with examples for most core functions: 4Clojure is a great way to build your clojure/FP skills: Clojure-doc.org (yes, really) has a number of getting started articles: Got a suggestion?