Introduction to clojure
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Clojure is a Lisp dialect created by Rich Hickey in 2008 that runs on the Java Virtual Machine. It is a dynamic, functional programming language with immutable persistent data structures and supports proper equality semantics. Clojure code is made up of data structures and uses homoiconicity, where code is represented as standard data structures. It has many standard data types like integers, doubles, ratios, strings, symbols and keywords, as well as collection data structures like lists, vectors, and maps.
![Data Structures
● Lists (1 2 3)
● Vectors [1 2 3]
● Maps {:a 1 :b 2}
maps are functions of their keys
● Sets #{1 2}](https://image.slidesharecdn.com/introductiontoclojure-130912060114-phpapp02/85/Introduction-to-clojure-6-320.jpg)
![Functions
● First class values
○ (def five 5)
○ (def add-1 (fn[x] (+ x 1)))
○ (add-1 five) = 6
● Higher order functions (HOF)
● fn special op is used to create functions](https://image.slidesharecdn.com/introductiontoclojure-130912060114-phpapp02/85/Introduction-to-clojure-12-320.jpg)
Introduction to clojure
- 1. Introduction to Clojure By Abhishek Mahawar BM Tech Talk
- 2. Not so old History ● Created by Rich Hickey ● First version in 2008 ● Origin of name - Wanted to involve c(c#), l (lisp) and j(java).
- 3. Clojure is a …. ● LISP dialect targeting the JVM ● Dynamic programming language ● Functional programming language ● Compiled language
- 4. Clojure is a LISP ● S-expressions (Polish notation) (+ 2 4) ● Homoiconicity code is data, data is code ● Reader Operator/function names Arguments
- 5. Atomic Data Types ● Arbitrary precision integers 123 ● Doubles 1.23 , BigDecimals 1.23M ● Ratios 22/7 ● Strings “bm” , Characters b ● Symbols bm , Keywords :bm ● Booleans true false, Null - nil
- 6. Data Structures ● Lists (1 2 3) ● Vectors [1 2 3] ● Maps {:a 1 :b 2} maps are functions of their keys ● Sets #{1 2}
- 7. Data Structures (contd.) ● Clojure data structures are ○ persistent ■ previous version remains intact when modified ○ immutable ○ support proper equality semantics in their implementation of equals
- 8. Syntax ● We’ve just seen it !! ● No text based syntax ● Data structures are the code Homoiconicity ● Actually, syntax is in the interpretation of data structures
- 10. Expressions ● Everything is an expression ● All data literals represent themselves, except ○ symbols - looks for binding to value ○ lists - an operation form ■ (operation arguments) ■ operation can be special ops, macros or functions
- 11. Special ops/forms ● Can have non-normal evaluation of arguments ○ (def name value-expr) ○ (if test-expr then-expr else-expr) ■ conditional, evaluates only one of then/else ● fn, let, loop, recur, do, new, ., throw, try, set!, quote, var, monitor-enter, monitor- exit
- 12. Functions ● First class values ○ (def five 5) ○ (def add-1 (fn[x] (+ x 1))) ○ (add-1 five) = 6 ● Higher order functions (HOF) ● fn special op is used to create functions
- 13. Lots of other stuff ● Software Transactional Memory ● Macros ● Lazy Sequences ● Metadatas
- 14. References ● http://clojure.org/ ● http://www.youtube.com/clojuretv ● Clojure Programming by Chas Emerick, Brian Carper and Christophe Grand