Clojure


What Is Clojure?

  • A functional programming language 
  • Runs on the JVM, CLR, and wherever javascript runs
  • A Lisp

The Lispyness of clojure

"Lisp is the only language with the moxie to expose the AST as the language" - Someone
2 + 3 * 4 - 5              (- (+ 2 (* 3 4)) 5)

On The JVM (and clr & Javascript)

  • Great java interop
  • Produces Java byte code
  • As portable as java
  • Good concurrency support
  • Garbage collected

Tooling

  • Leiningen 
  • Lighttable/emacs/vi/IntelliJ (others?)
  • Clojars (and other artifact repositories from Java land)
  • Jenkins

REPL DEVELOPMENT

  • Instant feedback as you develop
  • Easy to explore APIs
  • More on this in the demo...

A Functional Language

  • Higher Order Functions (functions can be passed as arguments to other functions)
  • Immutable Data Structures
  • Promotes hygienic, side effect free writing, allows it when you need it
  • Recursion

Let's Think of AN Example!

  • We have a non-relational database full of contacts
  • We want to grab the e-mail address
  • If it's a gmail user, we want to e-mail them and let them know that gmail might be filtering us to promotions, and please move us out of promotions.
  • Demo Code: https://github.com/philipsdoctor/clojure-talk-demo

For a Bit more Fun, lets try CLJS!

  • Clojurescript compiles to javascript and then runs in your browser
  • Syntactically almost identical to clojure
  • Good JS interop
  • Very young, still growing quickly
  • Back to code !

Closing Thoughts

The Good
  • Super short code
  • REPL development
  • Easy to test/few bugs
  • A LOT OF FUN!

The Bad
  • Tech is still young, especially cljs, expect added dev time for warts
  • Documentation is mostly non-existent for most libraries, prepare to github
  • Stack traces are the worst I've ever seen in my life

Clojure

By Philip Doctor

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Clojure

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