Clojure Introduction.

Transcript

1. Clojure Lauro Caetano 14/01/2014
2. Just an introduction
3. • Intro (Syntax, Data Structures, Functions) • Persistent Data Structures • Macros • Famous projects • Should I use Clojure? • Learn more.
4. • Clojure is a dynamic programming language that targets the Java Virtual Machine. • Clojure is a dialect of Lisp (code as data). • Functional (features a rich set of immutable, persistent data structure). • When mutable state is needed, Clojure offers a software transactional memory system and reactive Agent system that ensure clean, correct, multithreaded designs.
5. • All operations have this form: (operator operands)
6. • Other languages mixes infix notation, dot operators and parentheses. Example:
7. • Nil, String, numbers, keywords, symbols, collections…
8. • Collections are immutable and persistent.
9. • Maps are similar to dictionaries or hashes in other languages. They are a way of associating some value with some other value.
10. • Vector is similar to an Array.
11. • Lists are similar to vector in that they are linear collections of values.
12. • Sets are collections of unique values.
13. • Functions
14. • Clojure evaluates all function arguments recursively before passing them to the function.
15. • Valid function calls
16. • Persistent Data Structures.
17. • There is no Clojure equivalent for the following Ruby:
18. • Ok.. Immutable, but what about persistent?
19. • While persistence can be achieved by simple copying, this is inefficient in CPU and RAM usage, because most operations make only small changes to a data structure.
20. • A better method is to exploit the similarity between the new and old versions to share structure between them, such as using the same subtree in a number of tree structures. • (Fat Node, Path Copying, A combination)
21. • Macros
22. • Macro is a tool for transforming an arbitrary data structure into one which can be evaluated by Clojure. (Allows new syntax)
23. • the -> (threading macro)
25. • Famous Projects
29. • Should I use Clojure?
30. • Learn. • Improve the way you write code in other languages. • Motivation.
31. • Learn more
35. • References • https://github.com/clojure/clojure • clojure.org • http://en.wikipedia.org/wiki/ Persistent_data_structure • http://www.braveclojure.com/ • http://www.infoq.com/presentations/Value- Identity-State-Rich-Hickey