Becoming a f(P) master
(a.k.a. Functional Programming concepts explained by Pokémon)
RubyConf Online 2015
Hi!
- Computer Engineer
- Programming
- Electronics
- Math <3 <3
- Physics
- Lego
- Meetups
- Animals
- Coffee
- GIFs
DISCLAIMER
Introductory content
Pokémon, GIFs and theory
Whys are people talking so much about
Functional Programming?
Let me try:
WAT
It's simple:
- Lambda calculus
- Lisp
- Haskell
- Scala
- Clojure
- Papers
- Academia
- Category Theory
- λ
- λ
- λ
Pokémon
We give instructions to Pokémon in a battle
Programming
We also give instructions to code
i = i+1;
Pokémon
We must know how some things work:
Programming
We must know how to manage information in our software
- Data types
- Evolution
- How to group them
- Important attributes
- Business rules
- Pokémon types
- Evolution
- Team strategy
- EV/IV
- Moves
- Items
- Trades
level >=16
f(evol)
output level is the same as the input
How can I get a Charizard from a Charmander?
level >=16
f(evol)
output level is the same as the input
output level is the same as the input
f(up)
level = 36
level=36
f(evol)
level = 36
Or:
level >=36
f(evol)
output level is the same as the input
f(evol)
output level is the same as the input
Higher Order Function
f(x) => g(x) => h(x)
In some competitions, there is a maximum value for the sum of the levels of the Pokémon on the team
Team
- Charizard, lvl 100
- Lapras, lvl 100
- Dragonite, lvl 100
- Rhydon, lvl 100
- Pidgeotto, lvl 100
- Gengar, lvl 100
Level sum: 600
- Gengar, lvl 100
- Charizard, lvl 100
- Lapras, lvl 100
- Rhydon, lvl 100
- Pidgeotto, lvl 100
- Dragonite, lvl 100
Level sum: 600
- Lapras, lvl 100
- Gengar, lvl 100
- Charizard, lvl 100
- Rhydon, lvl 100
- Pidgeotto, lvl 100
- Dragonite, lvl 100
- Pidgeotto, lvl 100
- Lapras, lvl 100
- Gengar, lvl 100
- Dragonite, lvl 100
- Charizard, lvl 100
- Rhydon, lvl 100
Credits: @bitemyapp and @argumatronic - http://haskellbook.com/
sumEverythong AndGiveTheResult([100,100, 100,100,100,100])
fold|reduce|other_names
(reduce + [100 100 100 100 100 100]) ;;=> 600
What else can you have on your party rather than battle Pokémon?
Eggs
Team
- Charizard, lvl 100
- Lapras, lvl 100
- Dragonite, lvl 100
- Egg
- Pidgeotto, lvl 100
- Gengar, lvl 100
Level sum: 500
Egg does not interfere on the sum
Egg level = 0
Does not change the value
Egg works as an identity element to the level.
- Gengar, lvl 100
- Charizard, lvl 100
- Lapras, lvl 100
- Egg
- Pidgeotto, lvl 100
- Dragonite, lvl 100
Level sum: 500
- Lapras, lvl 100
- Gengar, lvl 100
- Charizard, lvl 100
- Egg
- Pidgeotto, lvl 100
- Dragonite, lvl 100
- Pidgeotto, lvl 100
- Lapras, lvl 100
- Gengar, lvl 100
- Dragonite, lvl 100
- Charizard, lvl 100
- Egg
reduce
(reduce + 0[100 100 100 100 100]) ;;=> 500
identity element
collection
MONOIDS
Game items
Game items
[
]
Collection
Game Items
[
]
Collection
(map upgrade )
;;=>
[
]
Game Items
[0]
[1]
Optional
Game Items
Optional
(map change )
;;=>
[
]
[
]
Game Items
[
]
In some part of the game you will have the badges
Future
Game Items
[
]
(map other_cont )
;;=>
[
]
Future
[ Pokéballs]
[ Bike ]
[ Badges ]
=>
=>
=>
[ Pokéballs]
[ Bike ]
[ Badges ]
[ Pokéballs]
[ Bike ]
[ Badges ]
=>
=>
=>
[ Pokéballs]
[ Bike ]
[ Badges ]
FUNCTORS
Move set
and moves
{Surf: 15},
{Fissure: 5},
{Solarbeam: 10},
{Eruption: 5}
Moves
[
]
↓
{Surf: 15},
{Fissure: 5},
{Solarbeam: 10},
{Eruption: 5}
Moves
decrease_pp_used_move[{Surf: 15}]
[
]
[{Surf: 14}],
{Fissure: 5},
{Solarbeam: 10},
{Eruption: 5}
[
]
[]
[ ]
[ ]
↓
↓
↓
{Surf: 15},
{Fissure: 5},
{Solarbeam: 10},
{Eruption: 5}
Moves
[
]
{Surf: 14},
{Fissure: 5},
{Solarbeam: 10},
{Eruption: 5}
(flatten decrease_pp [{Surf:15}])
;;=> [{Surf: 14}, {Fissure: 5}, {Solarbeam: 10}, {Eruption: 5}]
Collection
↓
↓
Item
[Scope Lens]
boost_move
{Fissure:5},
{Surf:15},
{Solarbeam: 10},
{Eruption: 5}
[
]
↓
↓
↓
↓
{Fissure:5},
[{Surf:15:boosted}],
{Solarbeam: 10},
{Eruption: 5}
[
]
↓
Optional
Item
[Scope Lens]
{Fissure:5},
{Surf:15},
{Solarbeam: 10},
{Eruption: 5}
[
]
↓
↓
↓
↓
↓
Optional
(flatten boost_move [{Surf:15}]
;;=> [{Fissure:5}, {Surf: 15:boosted}, {Solarbeam: 10}, {Eruption: 5}]
{Fissure:5},
{Surf:15},
{Solarbeam: 10},
{Eruption: 5}
[
]
↓
↓
↓
↓
Future
{Fissure:5},
{Surf:15},
{Solarbeam: 10},
{Eruption: 5}
[
]
Moves
forget
{Fissure:5},
[],
{Solarbeam: 10},
{Eruption: 5}
[
]
{Fissure:5},
{Surf:15},
{Solarbeam: 10},
{Eruption: 5}
[
]
↓
↓
↓
↓
Future
(flatten forget [{Surf:15}]
;;=> [{Fissure:5}, {Solarbeam: 10}, {Eruption: 5]}
{Fissure:5},
{Surf:15},
{Solarbeam: 10},
{Eruption: 5}
[
]
Moves
No matter which move set you have (if it exists, if you have items, if you haven't learned the move yet):
- Get the element
- Apply a function if convenient
- flatten
- Allow call chain
MONADS
"Meownads!" (credits with @_leticia)
Quick: Where do I use that?
More credits and references:
- @lafp (wonderful GIFs)
- @bitemyapp, @argumatronic and @FunctionalWorks
- @txustice - http://blog.txus.io/
- http://www.amazon.com/Functional-Programming-Practice-Bruce-Maclennan/dp/0201137445/ref=sr_1_9?ie=UTF8&qid=1445967378&sr=8-9&keywords=functional+programming
- http://media.eurucamp.org/ (@eurucamp)
- @_leticia ('Meownads')
- http://stackoverflow.com/questions/2704652/monad-in-plain-english-for-the-oop-programmer-with-no-fp-background
Thank you! :)
Questions?
hannelita@gmail.com
@hannelita
RubyconfOnline pokemons_fp_en
By Hanneli Tavante (hannelita)