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matt aimonetti
@merbist
http://matt.aimonetti.net
http://github.com/mattetti
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special
day!
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f
dia de los muertos
x
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Human
Languages
studied by linguists
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Sapir-Whorf
Hypothesis
linguistic differences have consequences
on human cognition and behavior
The principle of linguistic relativity holds that the
structure of a language affects the ways in which its
speakers conceptualize their world, i.e. their world
view, or otherwise influences their cognitive
processes.
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Studying
Programming
Languages
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How
not
to do it
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Hello World!
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Syntax
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How
to
do it
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Karl Marx
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Not Karl Marx
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interpreted compiled
dynamically
typed
statically
typed
object
oriented
functional difficulty
JavaScript X X X* X easy
Ruby/Python X X X X normal
CoffeeScript X X X X normal
Objective-C X X X X * nightmare
Java X X X hard
Go X *
structural
X X* X normal
Clojure X X (hints)
* X normal/
nightmare/
hell
Scala X *
structural
X
inferred
X X normal/
nightmare
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Part I
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How did that
affect the way
I write Ruby?
Part II
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Format
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class Presentation
attr_accessor :name, :topic
def initialize(name, topic)
self.name = name
self.topic = topic
end
def start
puts "Hi, my name is #{name} \
and I will talk about #{topic}."
end
end
talk = Presentation.new("Matt", "Ruby")
talk.start
code example ported to each language
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.Use case
.Philosophy
.what I dislike
.what I like
.where to start
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Go
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compiled
structural typed
object oriented*
functional
learning: normal
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package demo
import "fmt"
type Presentation struct {
" Name, Topic string
}
func (p *Presentation) start() string {
" return "This is " + p.Name +
", and I will talk about " + p.Topic + "."
}
func main() {
" talk := &Presentation{Name: "Matt", Topic: "Go"}
" fmt.Println(talk.start())
}
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Use case:
concurrency
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package main
import (
" "fmt"
" "net/http"
" "time"
)
var urls = []string{
" "http://rubyconf.com/",
" "http://golang.org/",
" "http://matt.aimonetti.net/",
}
type HttpResponse struct {
" url string
" response *http.Response
" err error
}
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func asyncHttpGets(urls []string) []*HttpResponse {
" ch := make(chan *HttpResponse, len(urls)) // buffered
" responses := []*HttpResponse{}
" for _, url := range urls {
" " go func(url string) {
" " " fmt.Printf("Fetching %s \n", url)
" " " resp, err := http.Get(url)
" " " ch <- &HttpResponse{url, resp, err}
" " }(url)
" }
" for {
" " select {
" " case r := <-ch:
" " " fmt.Printf("%s was fetched\n", r.url)
" " " responses = append(responses, r)
" " " if len(responses) == len(urls) {
" " " " return responses
" " " }
" " default:
" " " fmt.Printf(".")
" " " time.Sleep(5e7)
" " }
" }
" return responses
}
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func main() {
" results := asyncHttpGets(urls)
" for _, result := range results {
" " fmt.Printf("%s status: %s\n", result.url,
result.response.Status)
" }
}
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$ go build concurrency_example.go && ./a.out
.Fetching http://rubyconf.com/
Fetching http://golang.org/
Fetching http://matt.aimonetti.net/
.....http://golang.org/ was fetched
.......http://rubyconf.com/ was fetched
.http://matt.aimonetti.net/ was fetched
http://golang.org/ status: 200 OK
http://rubyconf.com/ status: 200 OK
http://matt.aimonetti.net/ status: 200 OK
http://bit.ly/go-async-http
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Philosophy
The new “C”
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what I dislike
A bit too low level for some
Not so great GC
Limited adoption*
Odd conventions at times
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what I like
simple specs
modern std libs
concurrency (goroutines/channels)
sensible conventions
fast compilation
flexible code organization
simpler take on OO
features of FP
error handling
documentation
source as documentation
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how to get
started
http://tour.golang.org
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Clojure
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compiled
dynamically typed (w/ hints)
functional
“object oriented*”
learning: normal/nightmare
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(defprotocol Talk "A conference talk"
(start [p] "return the speaker and topic."))
(defrecord Presentation [name topic]
Talk; implement the Talk protocol
(start [_] (str "Hi, this is " name
" and I will talk about "
topic ".")))
(def talk (Presentation. "Matt" "Clojure"))
(start talk)
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Use case:
Data Processing
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(ns example.word-count
(:use clojure.contrib.io
clojure.contrib.seq-utils))
(defn parse-line [line]
(let [tokens (.split (.toLowerCase line) " ")]
(map #(vector % 1) tokens)))
(defn combine [mapped]
(->> (apply concat mapped)
(group-by first)
(map (fn [[k v]]
{k (map second v)}))
(apply merge-with conj)))
(defn sum [[k v]]
{k (apply + v)})
(defn reduce-parsed-lines [collected-values]
(apply merge (map sum collected-values)))
(defn word-frequency [filename]
(->> (read-lines filename)
(map parse-line)
(combine)
(reduce-parsed-lines)))
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Philosophy
The pragmatic Scheme
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what I dislike
not so simple
not always consistent
need to know a lot of functions/macros
not really web focused
brain stack overflow
hard mental context switch
meaningless error stacks
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what I like
really great for data processing
isolate problems efficiently
fast
java interop
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how to get
started
https://github.com/functional-koans/clojure-koans
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compiled
static/inferred/dynamic type
object oriented & functional
Learning: normal/hard
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class Presentation(val name: String,
val topic: String) {
val start = "My name is "+ name +
" and I will talk about " +
topic +"."
}
val talk = new Presentation("Matt", "Scala")
talk.start
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Use case:
Service Oriented Architecture
Whenever you need a more
“entreprisey” Ruby
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Twitter’s Finagle
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Future +
pipeline
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val authenticatedUser: Future[User] =
User.authenticate(email, password)
val lookupTweets: Future[Seq[Tweet]] =
authenticatedUser flatMap { user =>
Tweet.findAllByUser(user)
}
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for {
user <- User.authenticate(email, password)
tweets <- Tweet.findAllByUser(user)
} yield tweets
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Async, blocking or not futures
FP & OOP both fully embraced
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val service = new Service[HttpRequest, HttpResponse] {
def apply(request: HttpRequest) =
Future(new DefaultHttpResponse(HTTP_1_1, OK))
}
val address = new InetSocketAddress(10000)
val server: Server[HttpRequest, HttpResponse] = ServerBuilder()
.name("MyWebServer")
.codec(Http())
.bindTo(address)
.build(service)
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Enumerable
Anonymous methods
Default method param
Meta programming
method_missing
duck typing
Mixins
Focus on testing
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Focus on Tests
Inner methods
Lazy evals/streams
Great GC
Performance
Tools/IDE
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Philosophy
The academic version of Ruby
Ruby
minus scripting
plus static typing
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what I dislike
huge surface
stiff learning curve
abused o_O:: syntax
poor documentation
feels like it’s trying to do everything
JVM
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what I like
Close to Ruby/Python
Does a lot of what Clojure offers
Easy to get started
Inferred types
Flexible functional approach
Modern concerns (parallelism)
Pattern matching
Relatively rich ecosystem
Community
JVM/CLR
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where to get
started
Twitter’s Scala school
A Tour of scala
Coursera’s online class
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How did that
affect the way
I write Ruby?
Part II
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Ruby is (also)
a functional
programming
language
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fp & oop
are complementary
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fp when extend
with new operations
oop when extend
with new data
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fp when your data
doesn’t change
oop when your data
evolves
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It’s not because
you can
that you should
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Typing
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Testing
!=
Documentation
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Error handling
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Compilers
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Simplicity matters
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Ruby’s limits
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Performance
Concurrency
Freedom
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“ruby”
developer
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problem
solver
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product
builder
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is just a
detail
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but choose
wisely
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languages
shape
how you
solve problems
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be
curious
learn
a new language
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and go build
awesome
stuff
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Feedback
Questions
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matt aimonetti
@merbist
http://matt.aimonetti.net
http://github.com/mattetti
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