ruby-refinements/index.html at master · mooreniemi/ruby-refinements · GitHub

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<!doctype html>
<html>
  <head>
    <meta charset="utf-8">
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    <title>ruby refinements</title>

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    <div class="reveal">
      <div class="slides">
        <section>
          <h3>let's do ruby refinements!</h3>
          <img src="Ruby_Ready.png" style="border:none; background: none; box-shadow: none; height: 200px;"></section>
        <section>
          <h4>ruby has a nice central metaphor</h4>
          <pre>
              <code data-trim data-noescape class="ruby">
              receiver = Receiver.new
              receiver.message

              # or, implicit receiver
              message
              # => NameError: undefined local variable or method `message' for main:Object

              # this metaphor also applies to core types
              [1, 2, 3].first
              </code>
            </pre>
        </section>

        <section>
          <h4>but it has some limits...</h4>
          <pre>
              <code data-trim data-noescape class="ruby">
              class Cat
                def meow
                  "meow"
                end
                def louder
                  upcase + " said the cat"
                end
              end

              c = Cat.new
              c.meow.louder
              # => NoMethodError: undefined method `louder' for "meow":String
              </code>
            </pre>
        </section>

        <section>
          <h4>solution 1: wrap it in a method</h4>
          <pre>
              <code data-trim data-noescape class="ruby">
              class Cat
                def meow
                  "meow"
                end
                def louder(meow)
                  meow.upcase + " said the cat"
                end
              end

              c = Cat.new
              c.louder(c.meow)
              # => "MEOW said the cat"
              </code>
            </pre>
        </section>

        <section>
          <h4>solution 2: return self & use side-effects</h4>
          <pre>
              <code data-trim data-noescape class="ruby">
class Cat
  attr_reader :meow
  def meow
    @meow = "meow"
    self
  end
  def louder
    @meow.upcase + " said the cat"
  end
end

c = Cat.new
c.meow.louder
# => "MEOW said the cat"
              </code>
            </pre>
        </section>

        <section>
          <h4>solution 3: monkeypatch</h4>
<pre>
<code data-trim data-noescape class="ruby">
class String
  def louder
    upcase + " said the cat"
  end
end
</code>
</pre>
          <pre>
              <code data-trim data-noescape class="ruby">

class Cat
  def meow
    "meow"
  end
end

c = Cat.new
c.meow.louder
# => "MEOW said the cat"
              </code>
            </pre>
        </section>

        <section>
<ul>
  <li>solution 1: <span class="fragment">boilerplate 😫💢💔😟</span></li>
<li>solution 2: <span class="fragment">boilerplate 😱💩☣️</span></li>
<li>solution 3: <span class="fragment">no boilerplate!!! 😍💯💯👍</span></li>
</ul>
        </section>

        <section>
          <h5>monkeypatching is bad!!!!</h5>
          <img src="JasperHelmetVisor.png" style="border:none; background: none; box-shadow: none; height: 400px;">
          <img src="Worried_Ruby.png" style="border:none; background: none; box-shadow: none; height: 200px;">
        </section>

<section>
<h4>this is bad</h4>
<pre>
<code data-trim data-noescape class="ruby">
class Array
  def first
    if rand(1..10) == 1
      'wat'
    else
      super
    end
  end
end
</code>
</pre>
</section>

<section>
<h4>fine!! i love boilerplate! ill just write that FOREVER</h4>
<img src="Mad_Ruby.png" style="border:none; background: none; box-shadow: none;">
</section>

<section>
<h4>hold up. you can...</h4>
<img src="NewGarnetRev.png" style="border:none; background: none; box-shadow: none;">
</section>
        <section>
          <h4>✨refine it✨</h4>
<pre>
<code data-trim data-noescape class="ruby">
module Loud
  refine String do
    def louder
      upcase + " said the cat"
    end
  end
end
</code>
</pre>
          <pre>
              <code data-trim data-noescape class="ruby">

class Cat
  def meow
    "meow"
  end
end

<mark>using Loud</mark>
c = Cat.new
c.meow.louder
# => "MEOW said the cat"
              </code>
            </pre>
        </section>

        <section>
<h4><a href="https://docs.ruby-lang.org/en/2.4.0/syntax/refinements_rdoc.html">refinements</a> will respect scope</h4>
<pre>
<code data-trim data-noescape class="ruby">
# not activated here
class Foo
  # not activated here
  def foo
    # not activated here
  end
  using M
  # activated here
  def bar
    # activated here
  end
  # activated here
end
# not activated here
</code>
</pre>
<h4 class="fragment">(which is why it beats monkeypatching 🍌)</h4>
        </section>

        <section>
          <h3>examples</h3>
          <img src="ruby.png" style="border:none; background: none; box-shadow: none; height: 200px;">
          </section>
<section>
<h4>a real life example (part one)</h4>
<pre>
<code data-trim data-noescape class="ruby">
module HashFmap
  refine Hash do
    def fmap &block
      self.reduce({}) { |memo, (k,v)| memo.merge!({ k => block.call(v) }) }
    end
  end
end
</code>
</pre>
<pre>
<code data-trim data-noescape class="ruby">
h = {:foo=>"bar", :biz=>"baz"}
h.map {|k, v| v.upcase }
# => ["BAR", "BAZ"]

using HashFmap
h.fmap(&:upcase)
# => {:foo=>"BAR", :biz=>"BAZ"}
</code>
</pre>
</section>

<section>
<h4>a real life example (part two)</h4>
<pre>
<code data-trim data-noescape class="ruby">
module ThirdPartyAPIParams
  refine ModelOne do
    def params
      { ParamOne: 21 }
    end
  end
  refine ModelTwo do
    def params
      { ParamTwo: 22 }
    end
  end
end
</code>
</pre>
<pre>
<code data-trim data-noescape class="ruby">
class Worker
  using ThirdPartyAPIParams
  def perform(id, model)
    m = model.find(id)
    APIClient.post(m.params)
  end
end
</code>
</pre>
</section>

<section>
<h4>a real life example (part three)</h4>
<pre>
<code data-trim data-noescape class="ruby">
module MyWeirdFormatting
  refine Thing do
    def as_weird_format
      to_s.chars.map(&:ord).map {|c| c.to_s(2) }.join
    end
  end
end
</code>
</pre>
<pre>
<code data-trim data-noescape class="ruby">
class ThingService
  using MyWeirdFormatting
  attr_accessor :thing

  def initialize(thing)
    @thing = thing
  end
  def store
    $db.store(thing.id, thing.as_weird_format)
  end
end
</code>
</pre>
</section>

<section>
  <h3>re: why not just use a mixin or inheritence??</h3>
  <p class="fragment">Do you <i>really</i> need every method on your class everywhere your class appears?</p>
  <p class="fragment"><em>Really really??</em></p>
  <p class="fragment">My opinion: when an object has a smaller "surface area" of methods at base, and I extend its behavior explicitly in select contexts, I find it easier to reason about.</p>
</section>

<section>
<pre>
<code data-trim data-noescape class="ruby">
pry(main)> my_refined_object.methods
# => [ :to_s, :as_json, :inherited ]
pry(main)> my_object_bloated_with_mixins.methods
# => [ :to_s, :as_json, :random_method, :irrelevant, :wont_work, :inherited , :idc, :definitely_wrong, :mysterious ]
</code>
</pre>
<p>Literally, pry into some code and call .methods on it. What's truly useful for your receiver to accept as a message <em>in that calling context?</em></p>
</section>
<section>
  <h4>thanks for listening!</h4>
  <img src="ruby2.png" style="border:none; background: none; box-shadow: none; height: 200px;">
  <h4>questions?</h4>
</section>
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