Downloaded 15 times
![Data
literals
Keyword:
:a
Vector:
[1
2
3
4]
Hash
map:
{:a
1,
:b
2}
Set:
#{1
2
3
4}
List:
'(1
2
3
4)](https://image.slidesharecdn.com/han-okt-2015-151004104703-lva1-app6891/75/Full-Stack-Clojure-12-2048.jpg)
![Extensible
Data
NotaFon
{:key1"Bar"
:key2
[1
2
3]
"key3",
#{1.0
2.0
c}
:key4,{:foo
{:bar
{:baz
'hello}}}}
(pr-‐str
{:foo
"bar"})
(read-‐string
"{:foo
"bar"}")](https://image.slidesharecdn.com/han-okt-2015-151004104703-lva1-app6891/75/Full-Stack-Clojure-13-2048.jpg)
![JavaScript
-‐
ClojureScript
var
foo
=
{bar:
"baz"};
foo.bar
=
"baz";
foo["abc"]
=
17;
alert('foo')
new
Date().getTime()
new
Date().getTime().toString()
(def
foo
(js-‐obj
"bar"
"baz"))
(set!
(.-‐bar
foo)
"baz")
(aset
foo
"abc"
17)
(js/alert
"foo")
(.getTime
(js/Date.))
(..
(js/Date.)
(getTime)
(toString))
source:
hcp://himera.herokuapp.com/synonym.html](https://image.slidesharecdn.com/han-okt-2015-151004104703-lva1-app6891/75/Full-Stack-Clojure-18-2048.jpg)
![Persistent
data
structures
(def
v
[1
2
3])
(conj
v
4)
;;
=>
[1
2
3
4]
(get
v
0)
;;
=>
1
(v
0)
;;
=>
1](https://image.slidesharecdn.com/han-okt-2015-151004104703-lva1-app6891/75/Full-Stack-Clojure-19-2048.jpg)
![Sequence
abstracFon
Data
structures
as
seqs
(first
[1
2
3])
;;=>
1
(rest
[1
2
3])
;;=>
(2
3)
General
seq
funcNons:
map,
reduce,
filter,
...
(distinct
[1
1
2
3])
;;=>
(1
2
3)
(take
2
(range
10))
;;=>
(0
1)
See
hcp://clojure.org/cheatsheet
for
more](https://image.slidesharecdn.com/han-okt-2015-151004104703-lva1-app6891/75/Full-Stack-Clojure-24-2048.jpg)
![Sequence
abstracFon
Most
seq
funcNons
return
lazy
sequences:
(take
2
(map
(fn
[n]
(js/alert
n)
n)
(range)))
infinite
lazy
sequence
of
numbers
side
effect](https://image.slidesharecdn.com/han-okt-2015-151004104703-lva1-app6891/75/Full-Stack-Clojure-25-2048.jpg)
![Mutable
state:
atoms
(def
my-‐atom
(atom
0))
@my-‐atom
;;
0
(reset!
my-‐atom
1)
(reset!
my-‐atom
(inc
@my-‐atom))
;;
bad
idiom
(swap!
my-‐atom
(fn
[old-‐value]
(inc
old-‐value)))
(swap!
my-‐atom
inc)
;;
same
@my-‐atom
;;
4](https://image.slidesharecdn.com/han-okt-2015-151004104703-lva1-app6891/75/Full-Stack-Clojure-26-2048.jpg)
![Lisp:
macros
JVM
Clojure:
(defmacro
defonce
[x
init]
`(when-‐not
(exists?
~x)
(def
~x
~init)))
ClojureScript:
(defonce
foo
1)
(defonce
foo
2)
;;
no
effect
notes:
● macros
must
be
wricen
in
JVM
Clojure
● are
expanded
at
compile
Nme
● generated
code
gets
executes
in
ClojureScript](https://image.slidesharecdn.com/han-okt-2015-151004104703-lva1-app6891/75/Full-Stack-Clojure-29-2048.jpg)
Uploaded byMichiel Borkent
Full Stack Clojure
This document provides an overview and agenda for a presentation on Full Stack Clojure. It introduces Clojure and why it was designed, discusses some of its core principles like immutability and functional programming, and provides examples of basic Clojure concepts like data literals, syntax, and persistent data structures. The presentation aims to explain Clojure and demonstrate how to build full stack applications with it.
Full Stack Clojure
- 1. Full Stack Clojure Michiel Borkent @borkdude HAN University of Applied Sciences October 1st 2015
- 2. Agenda ● Part 1: Why Clojure ● Part 2: Some basic Clojure ● Part 3: Full stack Clojure
- 3. Part 1: Why Clojure
- 4. Clojure • Designed by Rich Hickey in 2007 • FrustraNon with Java, C++ • Deliver the same funcNonality faster • Without giving up operaNonal requirements
- 5. Non-‐goals • Easy to learn by Java etc. developers • Experiment in language design
- 6. Programs are (mostly) about data • Language should not get in the way of data • Good support for data literals • Data transformaNons • Data is immutable • OO is not great for working with data • Big part of program can be built using plain data
- 7. Systems and immutability • Each system receives a message and/or sends a message • MutaNng a message does not affect other system • In Java, references lead to uncontrolled mutaNon • You can protect yourself by using Value Objects or DTOs, but takes work • Clojure adopts system model in the small by using immutable data structures • MutaNon only happens in controlled and explicit ways
- 8. Clojure • dynamic language • lisp • funcNonal programming • immutable data structures • strong concurrency support • embraces host pla_orm (JVM, js) • EDN
- 9. Choosing a language is all about trade offs!
- 10. Clojure in industry hcps://www.youtube.com/watch?v=av9Xi6CNqq4 http://dev.clojure.org/display/community/Clojure+Success+Stories http://clojure.org/Companies
- 11. Part 2: Basic Clojure
- 12. Data literals Keyword: :a Vector: [1 2 3 4] Hash map: {:a 1, :b 2} Set: #{1 2 3 4} List: '(1 2 3 4)
- 13. Extensible Data NotaFon {:key1"Bar" :key2 [1 2 3] "key3", #{1.0 2.0 c} :key4,{:foo {:bar {:baz 'hello}}}} (pr-‐str {:foo "bar"}) (read-‐string "{:foo "bar"}")
- 14. f(x) -‐> (f x) Syntax
- 15. Syntax if (...) { ... } else { -‐> ... } (if ... ... ...)
- 16. Syntax var foo = "bar"; (def foo "bar")
- 17. JavaScript -‐ ClojureScript if (bugs.length > 0) { return 'Not ready for release'; } else { return 'Ready for release'; } (if (pos? (count bugs)) "Not ready for release" "Ready for release") source: hcp://himera.herokuapp.com/synonym.html
- 18. JavaScript -‐ ClojureScript var foo = {bar: "baz"}; foo.bar = "baz"; foo["abc"] = 17; alert('foo') new Date().getTime() new Date().getTime().toString() (def foo (js-‐obj "bar" "baz")) (set! (.-‐bar foo) "baz") (aset foo "abc" 17) (js/alert "foo") (.getTime (js/Date.)) (.. (js/Date.) (getTime) (toString)) source: hcp://himera.herokuapp.com/synonym.html
- 19. Persistent data structures (def v [1 2 3]) (conj v 4) ;; => [1 2 3 4] (get v 0) ;; => 1 (v 0) ;; => 1
- 20.
- 21. Persistent data structures (def m {:foo 1 :bar 2}) (assoc m :foo 2) ;; => {:foo 2 :bar 2} (get m :foo) ;;=> 1 (m :foo) ;;=> 1 (:foo m) ;;=> 1 (dissoc m :foo) ;;=> {:bar 2}
- 22. FuncFonal programming (def r (-‐>> (range 10) ;; (0 1 2 .. 9) (filter odd?) ;; (1 3 5 7 9) (map inc))) ;; (2 4 6 8 10) ;; r is (2 4 6 8 10)
- 23. FuncFonal programming ;; r is (2 4 6 8 10) (reduce + r) ;; => 30 (reductions + r) ;; => (2 6 12 20 30) var sum = _.reduce(r, function(memo, num){ return memo + num; });
- 24. Sequence abstracFon Data structures as seqs (first [1 2 3]) ;;=> 1 (rest [1 2 3]) ;;=> (2 3) General seq funcNons: map, reduce, filter, ... (distinct [1 1 2 3]) ;;=> (1 2 3) (take 2 (range 10)) ;;=> (0 1) See hcp://clojure.org/cheatsheet for more
- 25. Sequence abstracFon Most seq funcNons return lazy sequences: (take 2 (map (fn [n] (js/alert n) n) (range))) infinite lazy sequence of numbers side effect
- 26. Mutable state: atoms (def my-‐atom (atom 0)) @my-‐atom ;; 0 (reset! my-‐atom 1) (reset! my-‐atom (inc @my-‐atom)) ;; bad idiom (swap! my-‐atom (fn [old-‐value] (inc old-‐value))) (swap! my-‐atom inc) ;; same @my-‐atom ;; 4
- 27. Lisp: macros (map inc (filter odd? (range 10))) (-‐>> (range 10) (filter odd?) (map inc)) thread last macro
- 28. Lisp: macros (macroexpand '(-‐>> (range 10) (filter odd?))) ;; => (filter odd? (range 10)) (macroexpand '(-‐>> (range 10) (filter odd?) (map inc))) ;; => (map inc (filter odd? (range 10)))
- 29. Lisp: macros JVM Clojure: (defmacro defonce [x init] `(when-‐not (exists? ~x) (def ~x ~init))) ClojureScript: (defonce foo 1) (defonce foo 2) ;; no effect notes: ● macros must be wricen in JVM Clojure ● are expanded at compile Nme ● generated code gets executes in ClojureScript
- 30. Part 3: Full Stack Clojure
- 31. Full Stack Clojure Front-end (js) ClojureScript reagent + react secretary cljs-http figwheel REPL leiningen core.async Prismatic/Schema timbre Server side (JVM) Clojure ring compojure liberator environ hiccup Framework: Pedestal Persistence RDBMS (via JDBC, e.g. PostgresQL, MySQL, H2, etc) clojure.java.jdbc YesQL Datomic
- 32. Show me the code! https://github.com/borkdude/full-stack-clojure-han-okt-2015
- 33. Get started with Clojure(Script) • Read a Clojure(Script) book • Do the 4clojure exercises • Start hacking on your own project • Pick an online Clojure course • Join the AMSCLJ meetup • Join the Slack community