Intro scala for rubyists (ironhack)

Intro to scala

Ignasi Marimon-Clos (@ignasi35)

IronHack

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thanks!

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about you

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about me

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1) problem solver, Garbage Collector, scala, java8

2) kayaker

3) under construction

4) all things JVM

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ruby vs scala

more similar than you think

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ruby vs scala

√ Lambda + closures + currying

√ Collection manipulation (via lambdas)

√ traits (similar to modules)

√ No monkey patching

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ruby vs scala

https://twitter.com/raichoo/status/692089108022312960

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mri v jvm

http://www.slideshare.net/CharlesNutter/over-9000-jruby-in-2015

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mri v jvm

http://www.slideshare.net/CharlesNutter/over-9000-jruby-in-2015

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mri v jvm

http://jruby.org/bench9000/

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mri v jvm

http://jruby.org/bench9000/

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also: invoke scala from ruby !!

mri v jvm

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teh codez

source code

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teh codez

https://gist.github.com/ignasi35/65f729a9a65aa6296933b100026a0fa1source code

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Types

class PersonBuilder {

Person build(String name, String surname) { … }

}

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Types

class PersonBuilder {

Person build(Name name, Surname surname) { … }

}

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Case Classes

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Case Classes

Equality

Copy

Pattern Matching

Immutable

Syntactic Sugar

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Case Classes

Equality

Copy

Pattern Matching

Immutable

Syntactic Sugar

º

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Func Prog

Pure Functions

no side effects

if not used, remove it

fixed in — fixed out

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filter

f

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map

f

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fold

f

f

f

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fold

aka reduce

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map revisited

f

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f

map revisited

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map

f

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flatMap

f

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recap

filter

map

fold

flatMap

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Null Dealing

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Null Dealing

class PersonBuilder {

Person build(Name name, Option[Surname] surname) { … }

}

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Maybe (aka Option)

replaces null completely

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Maybe (aka Option)

replaces null completelyforever

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Maybe (aka Option)

replaces null completelyforever

and ever

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Maybe (aka Option)

replaces null completelyforever

and everand ever

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Maybe (aka Option)

replaces null completelyforever

and everand everand ever

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Maybe (aka Option)

replaces null completelyforever

and everand everand everand ever

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Maybe (aka Option)

replaces null completelyforever

and everand everand everand everand ever

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filter

f f f

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map

f f

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fold

f f

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Maybe (aka Option)

filter: applies predicate and Returns input or Nonemap: converts contentfold: returns Some(content) or Some(zero)flatMap: see list

get: returns content or throws ExceptiongetOrElse: returns content or defaultValue

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recap

filter

map

fold

flatMap

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W T F ! ? ! ?

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railway programming

https://fsharpforfunandprofit.com/posts/recipe-part2/

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INPUT

FAILURE SUCCESS

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REQUEST

401

RESPONSE

404

400

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railway programming

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Live Live coding

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Conclusions

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Conclusions

Read books

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Conclusions

Read teh bookz ! ! !

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Conclusions

because there’s no

One Tool To Rule Them All

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Conclusions

Use Types

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Conclusions

and immutabilty

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Conclusions

prepare for failures

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Conclusions

but don’t let it clutter your code

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Arigató

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Questions

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