diff --git a/Nothing-Is-Easy/images/6736130025_ac5e197e22_b.jpg b/Nothing-Is-Easy/images/6736130025_ac5e197e22_b.jpg
new file mode 100644
index 0000000..96bae57
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diff --git a/Nothing-Is-Easy/images/Booleans-talk.png b/Nothing-Is-Easy/images/Booleans-talk.png
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index 0000000..289acd5
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diff --git a/Nothing-Is-Easy/images/Bumblebee_Transformer_-_Flickr_-_andrewbasterfield.jpg b/Nothing-Is-Easy/images/Bumblebee_Transformer_-_Flickr_-_andrewbasterfield.jpg
new file mode 100644
index 0000000..dd86087
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diff --git a/Nothing-Is-Easy/images/OCR-A_char_Exclamation_Mark.svg b/Nothing-Is-Easy/images/OCR-A_char_Exclamation_Mark.svg
new file mode 100644
index 0000000..75fef6d
--- /dev/null
+++ b/Nothing-Is-Easy/images/OCR-A_char_Exclamation_Mark.svg
@@ -0,0 +1,68 @@
+
+
+
diff --git a/Nothing-Is-Easy/images/Obsession.png b/Nothing-Is-Easy/images/Obsession.png
new file mode 100644
index 0000000..af41712
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diff --git a/Nothing-Is-Easy/images/Thank-you-word-cloud.jpg b/Nothing-Is-Easy/images/Thank-you-word-cloud.jpg
new file mode 100644
index 0000000..e06b9f9
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diff --git a/Nothing-Is-Easy/images/background.webp b/Nothing-Is-Easy/images/background.webp
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index 0000000..176f22f
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diff --git a/Nothing-Is-Easy/images/background2.webp b/Nothing-Is-Easy/images/background2.webp
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index 0000000..f0af6fa
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diff --git a/Nothing-Is-Easy/images/blue-ridge-ruby-logo.svg b/Nothing-Is-Easy/images/blue-ridge-ruby-logo.svg
new file mode 100644
index 0000000..0a693b8
--- /dev/null
+++ b/Nothing-Is-Easy/images/blue-ridge-ruby-logo.svg
@@ -0,0 +1,31 @@
+
diff --git a/Nothing-Is-Easy/images/blue-ridge-ruby.svg b/Nothing-Is-Easy/images/blue-ridge-ruby.svg
new file mode 100644
index 0000000..4a53578
--- /dev/null
+++ b/Nothing-Is-Easy/images/blue-ridge-ruby.svg
@@ -0,0 +1,57 @@
+
diff --git a/Nothing-Is-Easy/images/books_bookshelf_computer_science_programming_computer_language_specialist_literature-1066570.jpg b/Nothing-Is-Easy/images/books_bookshelf_computer_science_programming_computer_language_specialist_literature-1066570.jpg
new file mode 100644
index 0000000..9a97871
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diff --git a/Nothing-Is-Easy/images/fairbank-title-slide.jpg b/Nothing-Is-Easy/images/fairbank-title-slide.jpg
new file mode 100644
index 0000000..d2d8b55
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diff --git a/Nothing-Is-Easy/images/pexels-photo-259943.jpeg b/Nothing-Is-Easy/images/pexels-photo-259943.jpeg
new file mode 100644
index 0000000..8682a9a
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diff --git a/Nothing-Is-Easy/slides.html b/Nothing-Is-Easy/slides.html
index e8d820e..3e13eb2 100644
--- a/Nothing-Is-Easy/slides.html
+++ b/Nothing-Is-Easy/slides.html
@@ -43,21 +43,23 @@
}
.remark-slides-area {
- background-color: #C6291C; /* Color of pillarbox on sides of slides */
+ background-color: #2672B5; /* Color of pillarbox on sides of slides */
}
.remark-slide-scaler {
background-color: white;
}
.remark-slide-content {
- background-color: #F4F4F4;
+ background-color: initial;
font-size: 26px; line-height: 1.6;
width: 100%;
}
+ /* Code */
.remark-code, .remark-inline-code { font-family: monospace; line-height: 1.5; font-size: 16px; }
.remark-inline-code { font-size: 24px; }
- .remark-code {
+ pre code.remark-code {
counter-reset: code-line-numbers;
+ background-color: rgba(240, 240, 240, 0.5) !important;
}
.remark-code .remark-code-line {
counter-increment: code-line-numbers;
@@ -71,27 +73,27 @@
-webkit-user-select: none; /* The line numbers should not be selectable. */
}
- /* Title page */
- .remark-slide .title h1 {
- font-size: 70px;
- margin-top: 0px;
- }
- .remark-slide .title li {
- list-style-type: none;
- font-size: 28px;
+ .remark-slide .remark-slide-content {
+ background-image: url(images/background2.webp);
}
- .remark-slide .title ul {
- padding-left: 0px;
+
+ /* Title page */
+ .remark-slide .remark-slide-content.title {
+ background-image: url(images/blue-ridge-ruby.svg), url(images/background2.webp);
+ background-position: 10% 80px, center;
+ background-size: 100%, auto;
+ background-origin: content-box;
+
}
- .remark-slide .title {
- background-image: url(images/f5-logo-gradient-rgb.png);
- background-position: 150px 400px;
+ .remark-slide .remark-slide-content.title h1 {
+ font-size: 72px;
+ margin-top: 160px;
+ color: #0C2866;
}
- .remark-slide .title h3 {
- font-size: 40px;
- margin-left: 200px;
- margin-top: 140px;
+ .remark-slide .remark-slide-content.title h2 {
+ color: #0C2866;
}
+
.remark-slide .diagram p {
text-align: center;
}
@@ -169,31 +171,13 @@
background-color: rgba(255, 255, 255, .75);
}
- .remark-slide .transition.boolean_basics {
+ .remark-slide .transition.basics {
background-image: url(images/pexels-photo-259943.jpeg);
}
- .remark-slide .transition.boolean_parameters {
- background-image: url(images/Param_03.jpg);
- }
- .remark-slide .transition.connascence {
- background-image: url(images/TwinsTwins.JPG);
- }
- .remark-slide .transition.boolean_states {
- background-image: url(images/Balkans_regions_map.png);
- }
.remark-slide .transition.primitive_obsession {
background-image: url(images/Obsession.png);
}
- .remark-slide .transition.boolean_fields {
- background-image: url(images/cornfield_sky_trees_cereals_summer_nature_field_clouds-450526.jpg);
- }
- .remark-slide .transition.exponential_complexity {
- background-image: url(images/Exponential.svg);
- }
- .remark-slide .transition.boolean_operations {
- background-image: url(images/operation.jpg);
- }
- .remark-slide .transition.boolean_transformations {
+ .remark-slide .transition.transformations {
background-image: url(images/Bumblebee_Transformer_-_Flickr_-_andrewbasterfield.jpg);
}
.remark-slide .transition.readability {
@@ -275,6 +259,18 @@
## A Talk About Nothing (Nil)
+???
+
+* This is a talk I'll be giving next Thursday at Blue Ridge Ruby
+* My Twitter is in the upper right corner if you want to tweet at/about me.
+ * I'm also on Mastodon, same username, @ruby.social
+ * I'm rarely on Twitter any more, nor Mastodon
+* AUDIENCE QUESTION: Who knows the costliest mistake in computer programming?
+ * ANSWER: Null pointers, according to Tony Hoare (who invented them)
+ * It has probably cost businesses several billion dollars over the years
+* AUDIENCE QUESTION: Who has seen a talk on Nil by Sandi Metz or Avdi Grimm?
+ * I've got some big boots to fill!
+
---
class: middle
@@ -291,14 +287,41 @@
* Hit `P` for presenter notes.
* Notes have links to things I reference.
* Notes have more info than I'll talk about in some cases.
-* My Twitter is in the upper right corner if you want to tweet at/about me.
- * I'm also on Mastodon, same username, @ruby.social
-* AUDIENCE QUESTION: Who knows the costliest mistake in computer programming?
- * ANSWER: Null pointers, according to Tony Hoare (who invented them)
- * It has probably cost businesses several billion dollars over the years
- * Second most costly mistake is automatic coercion to Booleans
-* AUDIENCE QUESTION: Who has seen a talk on Nil by Sandi Metz or Avdi Grimm?
- * I've got some big boots to fill!
+
+---
+class: middle, center, image-only
+
+
+
+???
+
+* One of my favorite conference talks was by Jeremy Fairbank.
+ * He talked about Booleans
+ * I wondered how he could talk about true and false for 40 minutes
+ * It turned out to be a great talk
+ * His talk was about Elm
+
+------
+
+* I highly recommend watching Jeremy's talk.
+ * video: [Solving the Boolean Identity Crisis by Jeremy Fairbank](https://www.youtube.com/watch?v=8Af1bh-BVY8)
+ * slides: [Slides for "Solving the Boolean Identity Crisis"](https://bit.ly/elm-bool)
+
+---
+class: middle, center, image-only
+
+
+
+
+???
+
+* That talk inspired me to give a talk on Booleans
+* And **that** talk inspired me to write this talk
+
+------
+
+* In my own opinion, this is the best conference talk I've given
+* http://craigbuchek.com/booleans
---
class: agenda
@@ -310,8 +333,8 @@
* NoMethodError
* Ruby's take on NullPointerException
* The Billion Dollar Mistake
-* Safe Navigation
* Other Anti-Patterns
+* Safe Navigation
* Null Object and Special Case
* Refactoring
* Type Safety
@@ -382,7 +405,7 @@
* true: 2
* nil: 4
-------
+--
* From the `object_id` documentation: "no two objects will share an id".
@@ -536,7 +559,7 @@
* It's more *idiomatic* to use something more explicitly intention-revealing that returns a Boolean.
* Like `nil?`, `empty?`, or `blank?`
-------
+--
* This isn't as big a problem in Ruby as in other languages.
* I contend that automatic coercion to Booleans is the 2nd most expensive mistake in computer language design.
@@ -573,6 +596,18 @@
# NoMethodError
+* Raised when a method is called on an object that does not support it
+* Nil has only a few methods
+
+~~~ ruby
+nil.to_s
+# => ""
+
+nil.
+~~~
+
+???
+
---
# Safe Navigation
@@ -691,228 +726,44 @@
* TODO: More on the Law of Demeter
---
-class: transition, parameters
+class: transition, root_causes
-# Parameters
-
-???
-
-* Next we'll talk about `nil` used in parameters to methods.
+# Root Causes
---
-# Parameters
-
-~~~ ruby
-random_object.class
-# => User
-~~~
-
-???
-
-* I spend a lot of time in Rails console, IRB, or Pry.
-* I'll often want to see the class of an object.
-
-------
-
-* I actually wrote a method to get a random object:
-
-~~~ ruby
-def random_object(cache: true)
- return @random_object if cache && @random_object_defined
- @random_object_defined = true
- random_object_index = Random.rand(ObjectSpace.each_object.count)
- @random_object = ObjectSpace.each_object.drop(random_object_index).take(1)
-end
-~~~
-
----
-
-# Parameters
-
-~~~ ruby
-random_object.methods
-# => [:can?, :cannot?, :paper_trail_originator, :paper_trail_enabled_for_model?, :whodunnit]
-
-random_object.class.instance_methods
-# => [:can?, :cannot?, :paper_trail_originator, :paper_trail_enabled_for_model?, :whodunnit]
-~~~
-
-???
-
-* Often, I'll also want to see what methods the object can respond to.
-* I'll use a method that's on `Object`, named `methods`.
- * Or a method that's on `Class`, named `instance_methods`.
-* Notice that these usually return a long list of methods.
- * They're running off the right side of the text box here.
-* Show of hands - who's familiar with either of these methods?
-* How many of you (with your hands up) know that they take an optional parameter?
-* How many of you remember whether to pass `true` or `false` to not show methods from superclasses?
-
----
-
-# Parameters
-
-~~~ ruby
-random_object.methods(false)
-# => [:id, :first_name, :last_name]
-
-random_object.class.instance_methods(false)
-# => [:id, :first_name, :last_name]
-~~~
-
-???
-
-* It happens to be `false` for these methods.
-* But to use it properly, you have to remember that.
-* Can we do better?
-
----
-
-# Named Parameters
-
-~~~ ruby
-random_object.methods(superclass_methods: false)
-# => [:id, :first_name, :last_name]
-~~~
-
-???
-
-* The best way to fix this API is to use a named parameter to *describe* the parameter.
-* This method pre-dates named parameters in Ruby, though.
-* It also needs to retain backwards compatibility.
-
----
-
-# Named Parameters
-
-~~~ ruby
-class Object
- def methods(options = [])
- show_superclass_methods = options &&
- options.respond_to?(:[]) &&
- options[:superclass_methods]
- if show_superclass_methods
- show_all_methods_this_object_responds_to
- else
- show_methods_from_immediate_class_of_this_object
- end
- end
-end
-~~~
-
-???
-
-* In older Ruby versions, we would have to use an options hash to emulate named parameters.
-* We still need to use an options hash to support taking a bare Boolean or a Hash.
-
----
-
-# Single Responsibility Principle
-
-~~~ ruby
-random_object.methods
-# => [:id, :first_name, :last_name]
-
-random_object.all_methods
-# => [:can?, :cannot?, :paper_trail_originator, :paper_trail_enabled_for_model?, :whodunnit]
-~~~
-
-???
-
-* Ideally, it'd be best just to have 2 separate methods.
-
----
-
-# Single Responsibility Principle
-
-~~~ ruby
-random_object.methods(true)
-# => [:id, :first_name, :last_name]
-
-random_object.methods(false)
-# => [:can?, :cannot?, :paper_trail_originator, :paper_trail_enabled_for_model?, :whodunnit]
-~~~
-
-???
-
-* How would you describe what this original method does?
- * "Show the methods defined for this object OR the methods only defined by its immediate class."
-* Any time you have an "OR" (or "AND") in the description of a method or class, that's a code smell.
- * There's probably a violation of the Single Responsibility Principle.
-
----
-
-# An Example from Rails
-
-~~~ ruby
-user.things(true)
-
-user.things.reload
-~~~
-
-???
-
-* I came across this a couple months ago, when upgrading to Rails 5.
-* These both do the same thing.
-* The first one was the original API in Rails to reload an association.
-* The 2nd is the current API.
-* The original API is deprecated as of Rails 5, and removed as of Rails 5.1.
-* Not only is the new one clearer, but the old way can lead to some very subtle bugs.
-
----
-
-# An Example from Rails
-
-~~~ ruby
-@clients.sales(limit: 10)
-~~~
-
-???
-
-* This is [Rails issue #26413](https://github.com/rails/rails/issues/26413)
-* The bug report complains that the sales are being reloaded.
-* Show of hands - anyone see the issue?
-* The `sales` association doesn't take a hash, it takes a boolean.
-* Ruby treats the `limit: 10` hash as `true`, meaning "reload".
+# Multiple Meanings
+* Nil doesn't have a single meaning
+* It's often used to represent multiple things
+ * Missing value
+ * Empty value
+ * False
+ * Not found
+ * Not applicable
+ * Not supported
+ * Uninitialized / unset variable
+ * Failure
+ * Default value
+ * Sentinel value
+ * Placeholder value
+ * Empty set
---
class: transition, primitive_obsession
# Primitive Obsession
-???
-
-* The original version of that code contains a code smell named "primitive obsession".
-
---
# Primitive Obsession
-~~~ ruby
-class Editor
- attr_accessor :editing # boolean
- attr_accessor :saving # boolean
- attr_accessor :error # boolean
-
- def render
- if editing
- render_document
- elsif saving
- render_saving
- elsif error
- render_error_message
- end
- end
-end
-~~~
+* Using a primitive type when it'd be better to use a more specialized type
???
-* It's using a primitive type when it'd be better to use a more specialized type.
- * Example: Using a floating point number to represent money
- * Example: Using a string to represent a URL
+* Example: Using a floating point number to represent money
+* Example: Using a string to represent a URL
* In Ruby, we're more likely to abuse strings in this way.
* That's often referred to as "stringly typed".
* A play on "strongly typed" languages.
@@ -922,24 +773,7 @@
# Primitive Obsession
-~~~ ruby
-class Editor
- attr_accessor :state # symbol
-
- def render
- case state
- when :editing
- render_document
- when :saving
- render_saving
- when :error
- render_error_message
- else
- fail "This shouldn't happen"
- end
- end
-end
-~~~
+*
???
@@ -1031,7 +865,7 @@
* One reason I give talks at conferences is to start a conversation.
* Please don't hesitate to come talk to me any time during the conference.
-------
+--
* I used a tool called [Remark][remark] to create and show these slides.
diff --git a/Nothing-Is-Easy/slides.html.erb b/Nothing-Is-Easy/slides.html.erb
index bb839e4..f1b9c0f 100644
--- a/Nothing-Is-Easy/slides.html.erb
+++ b/Nothing-Is-Easy/slides.html.erb
@@ -43,21 +43,23 @@
}
.remark-slides-area {
- background-color: #C6291C; /* Color of pillarbox on sides of slides */
+ background-color: #2672B5; /* Color of pillarbox on sides of slides */
}
.remark-slide-scaler {
background-color: white;
}
.remark-slide-content {
- background-color: #F4F4F4;
+ background-color: initial;
font-size: 26px; line-height: 1.6;
width: 100%;
}
+ /* Code */
.remark-code, .remark-inline-code { font-family: monospace; line-height: 1.5; font-size: 16px; }
.remark-inline-code { font-size: 24px; }
- .remark-code {
+ pre code.remark-code {
counter-reset: code-line-numbers;
+ background-color: rgba(240, 240, 240, 0.5) !important;
}
.remark-code .remark-code-line {
counter-increment: code-line-numbers;
@@ -71,27 +73,27 @@
-webkit-user-select: none; /* The line numbers should not be selectable. */
}
- /* Title page */
- .remark-slide .title h1 {
- font-size: 70px;
- margin-top: 0px;
- }
- .remark-slide .title li {
- list-style-type: none;
- font-size: 28px;
+ .remark-slide .remark-slide-content {
+ background-image: url(images/background2.webp);
}
- .remark-slide .title ul {
- padding-left: 0px;
+
+ /* Title page */
+ .remark-slide .remark-slide-content.title {
+ background-image: url(images/blue-ridge-ruby.svg), url(images/background2.webp);
+ background-position: 10% 80px, center;
+ background-size: 100%, auto;
+ background-origin: content-box;
+
}
- .remark-slide .title {
- background-image: url(images/f5-logo-gradient-rgb.png);
- background-position: 150px 400px;
+ .remark-slide .remark-slide-content.title h1 {
+ font-size: 72px;
+ margin-top: 160px;
+ color: #0C2866;
}
- .remark-slide .title h3 {
- font-size: 40px;
- margin-left: 200px;
- margin-top: 140px;
+ .remark-slide .remark-slide-content.title h2 {
+ color: #0C2866;
}
+
.remark-slide .diagram p {
text-align: center;
}
@@ -169,31 +171,13 @@
background-color: rgba(255, 255, 255, .75);
}
- .remark-slide .transition.boolean_basics {
+ .remark-slide .transition.basics {
background-image: url(images/pexels-photo-259943.jpeg);
}
- .remark-slide .transition.boolean_parameters {
- background-image: url(images/Param_03.jpg);
- }
- .remark-slide .transition.connascence {
- background-image: url(images/TwinsTwins.JPG);
- }
- .remark-slide .transition.boolean_states {
- background-image: url(images/Balkans_regions_map.png);
- }
.remark-slide .transition.primitive_obsession {
background-image: url(images/Obsession.png);
}
- .remark-slide .transition.boolean_fields {
- background-image: url(images/cornfield_sky_trees_cereals_summer_nature_field_clouds-450526.jpg);
- }
- .remark-slide .transition.exponential_complexity {
- background-image: url(images/Exponential.svg);
- }
- .remark-slide .transition.boolean_operations {
- background-image: url(images/operation.jpg);
- }
- .remark-slide .transition.boolean_transformations {
+ .remark-slide .transition.transformations {
background-image: url(images/Bumblebee_Transformer_-_Flickr_-_andrewbasterfield.jpg);
}
.remark-slide .transition.readability {
diff --git a/Nothing-Is-Easy/slides.md b/Nothing-Is-Easy/slides.md
index 399ff37..feb3ba0 100644
--- a/Nothing-Is-Easy/slides.md
+++ b/Nothing-Is-Easy/slides.md
@@ -17,6 +17,18 @@ class: title, middle, center
## A Talk About Nothing (Nil)
+???
+
+* This is a talk I'll be giving next Thursday at Blue Ridge Ruby
+* My Twitter is in the upper right corner if you want to tweet at/about me.
+ * I'm also on Mastodon, same username, @ruby.social
+ * I'm rarely on Twitter any more, nor Mastodon
+* AUDIENCE QUESTION: Who knows the costliest mistake in computer programming?
+ * ANSWER: Null pointers, according to Tony Hoare (who invented them)
+ * It has probably cost businesses several billion dollars over the years
+* AUDIENCE QUESTION: Who has seen a talk on Nil by Sandi Metz or Avdi Grimm?
+ * I've got some big boots to fill!
+
---
class: middle
@@ -33,14 +45,41 @@ class: middle
* Hit `P` for presenter notes.
* Notes have links to things I reference.
* Notes have more info than I'll talk about in some cases.
-* My Twitter is in the upper right corner if you want to tweet at/about me.
- * I'm also on Mastodon, same username, @ruby.social
-* AUDIENCE QUESTION: Who knows the costliest mistake in computer programming?
- * ANSWER: Null pointers, according to Tony Hoare (who invented them)
- * It has probably cost businesses several billion dollars over the years
- * Second most costly mistake is automatic coercion to Booleans
-* AUDIENCE QUESTION: Who has seen a talk on Nil by Sandi Metz or Avdi Grimm?
- * I've got some big boots to fill!
+
+---
+class: middle, center, image-only
+
+
+
+???
+
+* One of my favorite conference talks was by Jeremy Fairbank.
+ * He talked about Booleans
+ * I wondered how he could talk about true and false for 40 minutes
+ * It turned out to be a great talk
+ * His talk was about Elm
+
+------
+
+* I highly recommend watching Jeremy's talk.
+ * video: [Solving the Boolean Identity Crisis by Jeremy Fairbank](https://www.youtube.com/watch?v=8Af1bh-BVY8)
+ * slides: [Slides for "Solving the Boolean Identity Crisis"](https://bit.ly/elm-bool)
+
+---
+class: middle, center, image-only
+
+
+
+
+???
+
+* That talk inspired me to give a talk on Booleans
+* And **that** talk inspired me to write this talk
+
+------
+
+* In my own opinion, this is the best conference talk I've given
+* http://craigbuchek.com/booleans
---
class: agenda
@@ -52,8 +91,8 @@ class: agenda
* NoMethodError
* Ruby's take on NullPointerException
* The Billion Dollar Mistake
-* Safe Navigation
* Other Anti-Patterns
+* Safe Navigation
* Null Object and Special Case
* Refactoring
* Type Safety
@@ -124,7 +163,7 @@ c.object_id
* true: 2
* nil: 4
-------
+--
* From the `object_id` documentation: "no two objects will share an id".
@@ -278,7 +317,7 @@ v = nil
* It's more *idiomatic* to use something more explicitly intention-revealing that returns a Boolean.
* Like `nil?`, `empty?`, or `blank?`
-------
+--
* This isn't as big a problem in Ruby as in other languages.
* I contend that automatic coercion to Booleans is the 2nd most expensive mistake in computer language design.
@@ -315,6 +354,18 @@ nil.to_h
# NoMethodError
+* Raised when a method is called on an object that does not support it
+* Nil has only a few methods
+
+~~~ ruby
+nil.to_s
+# => ""
+
+nil.
+~~~
+
+???
+
---
# Safe Navigation
@@ -433,228 +484,44 @@ address = params.dig(:account, :owner, :address)
* TODO: More on the Law of Demeter
---
-class: transition, parameters
-
-# Parameters
+class: transition, root_causes
-???
-
-* Next we'll talk about `nil` used in parameters to methods.
+# Root Causes
---
-# Parameters
-
-~~~ ruby
-random_object.class
-# => User
-~~~
-
-???
-
-* I spend a lot of time in Rails console, IRB, or Pry.
-* I'll often want to see the class of an object.
-
-------
-
-* I actually wrote a method to get a random object:
-
-~~~ ruby
-def random_object(cache: true)
- return @random_object if cache && @random_object_defined
- @random_object_defined = true
- random_object_index = Random.rand(ObjectSpace.each_object.count)
- @random_object = ObjectSpace.each_object.drop(random_object_index).take(1)
-end
-~~~
-
----
-
-# Parameters
-
-~~~ ruby
-random_object.methods
-# => [:can?, :cannot?, :paper_trail_originator, :paper_trail_enabled_for_model?, :whodunnit]
-
-random_object.class.instance_methods
-# => [:can?, :cannot?, :paper_trail_originator, :paper_trail_enabled_for_model?, :whodunnit]
-~~~
-
-???
-
-* Often, I'll also want to see what methods the object can respond to.
-* I'll use a method that's on `Object`, named `methods`.
- * Or a method that's on `Class`, named `instance_methods`.
-* Notice that these usually return a long list of methods.
- * They're running off the right side of the text box here.
-* Show of hands - who's familiar with either of these methods?
-* How many of you (with your hands up) know that they take an optional parameter?
-* How many of you remember whether to pass `true` or `false` to not show methods from superclasses?
-
----
-
-# Parameters
-
-~~~ ruby
-random_object.methods(false)
-# => [:id, :first_name, :last_name]
-
-random_object.class.instance_methods(false)
-# => [:id, :first_name, :last_name]
-~~~
-
-???
-
-* It happens to be `false` for these methods.
-* But to use it properly, you have to remember that.
-* Can we do better?
-
----
-
-# Named Parameters
-
-~~~ ruby
-random_object.methods(superclass_methods: false)
-# => [:id, :first_name, :last_name]
-~~~
-
-???
-
-* The best way to fix this API is to use a named parameter to *describe* the parameter.
-* This method pre-dates named parameters in Ruby, though.
-* It also needs to retain backwards compatibility.
-
----
-
-# Named Parameters
-
-~~~ ruby
-class Object
- def methods(options = [])
- show_superclass_methods = options &&
- options.respond_to?(:[]) &&
- options[:superclass_methods]
- if show_superclass_methods
- show_all_methods_this_object_responds_to
- else
- show_methods_from_immediate_class_of_this_object
- end
- end
-end
-~~~
-
-???
-
-* In older Ruby versions, we would have to use an options hash to emulate named parameters.
-* We still need to use an options hash to support taking a bare Boolean or a Hash.
-
----
-
-# Single Responsibility Principle
-
-~~~ ruby
-random_object.methods
-# => [:id, :first_name, :last_name]
-
-random_object.all_methods
-# => [:can?, :cannot?, :paper_trail_originator, :paper_trail_enabled_for_model?, :whodunnit]
-~~~
-
-???
-
-* Ideally, it'd be best just to have 2 separate methods.
-
----
-
-# Single Responsibility Principle
-
-~~~ ruby
-random_object.methods(true)
-# => [:id, :first_name, :last_name]
-
-random_object.methods(false)
-# => [:can?, :cannot?, :paper_trail_originator, :paper_trail_enabled_for_model?, :whodunnit]
-~~~
-
-???
-
-* How would you describe what this original method does?
- * "Show the methods defined for this object OR the methods only defined by its immediate class."
-* Any time you have an "OR" (or "AND") in the description of a method or class, that's a code smell.
- * There's probably a violation of the Single Responsibility Principle.
-
----
-
-# An Example from Rails
-
-~~~ ruby
-user.things(true)
-
-user.things.reload
-~~~
-
-???
-
-* I came across this a couple months ago, when upgrading to Rails 5.
-* These both do the same thing.
-* The first one was the original API in Rails to reload an association.
-* The 2nd is the current API.
-* The original API is deprecated as of Rails 5, and removed as of Rails 5.1.
-* Not only is the new one clearer, but the old way can lead to some very subtle bugs.
-
----
-
-# An Example from Rails
-
-~~~ ruby
-@clients.sales(limit: 10)
-~~~
-
-???
-
-* This is [Rails issue #26413](https://github.com/rails/rails/issues/26413)
-* The bug report complains that the sales are being reloaded.
-* Show of hands - anyone see the issue?
-* The `sales` association doesn't take a hash, it takes a boolean.
-* Ruby treats the `limit: 10` hash as `true`, meaning "reload".
+# Multiple Meanings
+* Nil doesn't have a single meaning
+* It's often used to represent multiple things
+ * Missing value
+ * Empty value
+ * False
+ * Not found
+ * Not applicable
+ * Not supported
+ * Uninitialized / unset variable
+ * Failure
+ * Default value
+ * Sentinel value
+ * Placeholder value
+ * Empty set
---
class: transition, primitive_obsession
# Primitive Obsession
-???
-
-* The original version of that code contains a code smell named "primitive obsession".
-
---
# Primitive Obsession
-~~~ ruby
-class Editor
- attr_accessor :editing # boolean
- attr_accessor :saving # boolean
- attr_accessor :error # boolean
-
- def render
- if editing
- render_document
- elsif saving
- render_saving
- elsif error
- render_error_message
- end
- end
-end
-~~~
+* Using a primitive type when it'd be better to use a more specialized type
???
-* It's using a primitive type when it'd be better to use a more specialized type.
- * Example: Using a floating point number to represent money
- * Example: Using a string to represent a URL
+* Example: Using a floating point number to represent money
+* Example: Using a string to represent a URL
* In Ruby, we're more likely to abuse strings in this way.
* That's often referred to as "stringly typed".
* A play on "strongly typed" languages.
@@ -664,24 +531,7 @@ end
# Primitive Obsession
-~~~ ruby
-class Editor
- attr_accessor :state # symbol
-
- def render
- case state
- when :editing
- render_document
- when :saving
- render_saving
- when :error
- render_error_message
- else
- fail "This shouldn't happen"
- end
- end
-end
-~~~
+*
???
@@ -773,7 +623,7 @@ class: thanks, image-only
* One reason I give talks at conferences is to start a conversation.
* Please don't hesitate to come talk to me any time during the conference.
-------
+--
* I used a tool called [Remark][remark] to create and show these slides.