Clojure

Clojure for Rubists Federico Brubacher @fbru02 Cubox S.A.

Warning • Lots of code

Warning • Lots of code • Lots of parenthesis

What is Clojure? • General purpose programming language.

What is Clojure? • General purpose programming language. • Dialect of Lisp that runs on the JVM

What is Clojure? • General purpose programming language. • Dialect of Lisp that runs on the JVM • “Programmable Programming Language” It is easy to implement DSL in it.

Some examples I • (+ 2 3) #=> 5

Some examples I • (+ 2 3) #=> 5 • (def my-list '(2 3 4)) #=> my-list

Some examples I • (+ 2 3) #=> 5 • (def my-list '(2 3 4)) #=> my-list • (ﬁrst my-list) #=> 2

Some examples I • (+ 2 3) #=> 5 • (def my-list '(2 3 4)) #=> my-list • (ﬁrst my-list) #=> 2 • (rest my-list) #=> (3 4)

Polish Notation • Operator on the left; operands on the right.

Some examples II

Functions & Closures

In Ruby... • method • unbound method • lambda • Proc • block

In Clojure... • fn

Functions & Closures

Let’s test this

Immutable Data types

Filter

Remove

Lazy Sequences

Disclaimer (ruby 1.9)

Another feature... Software Transactional Memory

S oftware

T ransactional

Memory

Refs Agents Atoms Vars Coordinated X Async X Retriable X X Thread local X

OOP vs Plain old Functions Locks and mutable data make programmers think complicated

OOP vs Plain old Functions Locks and mutable data make programmers think complicated Think locking policy to prevent deadlocks, livelocks, etc.

OOP vs Plain old Functions Locks and mutable data make programmers think complicated Think locking policy to prevent deadlocks, livelocks, etc. Don’t compose well

OOP vs Plain old Functions Locks and mutable data make programmers think complicated Think locking policy to prevent deadlocks, livelocks, etc. Don’t compose well Code reading is recursive speculation

It is better to have 100 functions operate on one data structure than to have 10 functions operate on 10 data structures." - Alan J. Perlis

http://blog.bestinclass.dk/index.php/2009/10/brians-functional-brain/

State is localized only stateful line in the entire model

Example Let’s put STM into practice!

Let’s see if this works

Two more functions

Transfer

Balance

Let’s test them!

Is it theadsafe!?

Almost! but not quite

Fixed Reads

There’s more • Macros • Homoiconic • Multimethods • Performance

Conclusions • I love Ruby and so should you.

Conclusions • I love Ruby and so should you. • I love Clojure and so should you.

Conclusions • I love Ruby and so should you. • I love Clojure and so should you. • They have different use cases

Conclusions • I love Ruby and so should you. • I love Clojure and so should you. • They have different use cases • I think Functional Programming Languages are the future

•Questions? • Thank you

Clojure

by Federico Brubacher on Oct 31, 2010

Accessibility

Categories

Tags

Upload Details

Usage Rights

Statistics

Clojure — Presentation Transcript