Convert to standardrb (#156)

- I mostly don’t care about this, but there are a couple of things that
  Standard does that I disagree with. They are inherited from Rubocop,
  but Standard fixes many of Rubocop’s nonsense rules.

  - Array literal wrappers %i[], %w[], etc. are just ugly and never
    should have become any sort of standard. I would be happier if this
    part of standard were just completely disabled, because it‘s
    unnecessary and wrong.

  - Quote literals having to be %q() is equally wrong. I’ve avoided the
    issue here because the generated gemspec uses both "unnecessary"
    quote literals (it’s necessary if I say it’s necessary) and the
    wrong wrappers (I wouldn’t use %q<>, but this is generated code).

- I still think that short hashes can be `{ foo: "bar" }`, but I’m
  mostly using Elixir these days, so I don’t mind `%{foo: "bar"}`, so
  I can get used to it in Ruby. It still feels wrong, almost 20 years
  in.

- There are semantic differences between and / &&, or / ||, but in some
  cases the reformatted code is substantially _worse_ to read. Again,
  I mostly don’t _care_ about this difference, but Rubocop’s insistence
  is silly; these should only be replaced where there _is_ ambiguity.

  - Replacing `x = foo or next` should never be replaced with `(x = foo)
    || next`. That’s replacing something that is somewhat readable with
    something damned-near unreadable. Both should be replaced with:

    ```ruby
    x = foo
    next unless x
    ```

- YAML.safe_load works differently between Psych 2.x and Psych 3.x, so
  some updates have been made to make that work cleanly.

Overall, this introduces a lot of churn, but I think will be easier to
deal with updates to `standardrb` instead of the rapid churn that has
been Rubocop.

.gitignore

@@ -13,3 +13,4 @@ publish
 test/cache.tst
 tmp/
 .byebug_history
+tags

.standard.yml

@@ -0,0 +1,4 @@
+parallel: true
+ruby_version: 2.0
+ignore:
+  - 'mime-types.gemspec'

Gemfile

@@ -3,9 +3,9 @@
 # NOTE: This file is present to keep Travis CI happy. Edits to it will not
 # be accepted.
 
-source 'https://rubygems.org/'
+source "https://rubygems.org/"
 
-gem 'mime-types-data', path: '../mime-types-data' if ENV['DEV']
+gem "mime-types-data", path: "../mime-types-data" if ENV["DEV"]
 
 gemspec
 

History.md

@@ -15,6 +15,7 @@
     [#150]. Removed Coveralls configuration.
   - Igor Victor added TruffleRuby to the Travis CI configuration [#149].
   - Koichi ITO loosened an excessively tight dependency [#147].
+  - Started using `standardrb` for Ruby formatting and validation.
 
 ## 3.3.1 / 2019-12-26
 
@@ -28,8 +29,7 @@
 
 - Administrivia:
 
-  - Olle Jonsson removed an outdated Travis configuration option (`sudo:
-    false`). [#142]
+  - Olle Jonsson removed an outdated Travis configuration option (`sudo: false`). [#142]
 
 ## 3.3 / 2019-09-04
 
@@ -64,8 +64,7 @@
     to be in the same family even if strict sorting would cause an
     unregistered type to be sorted first. [#132]
 
-  - Dillon Welch contributed a change that added `frozen_string_literal:
-    true` to files so that modern Rubies can automatically reduce duplicate
+  - Dillon Welch contributed a change that added `frozen_string_literal: true` to files so that modern Rubies can automatically reduce duplicate
     string allocations. [#135]
 
 - 2 bug fixes
@@ -169,8 +168,7 @@
       `x-` prefixes.
 
     - Improved initialization with an Array works so that extensions do not
-      need to be wrapped in another array. This means that `%w(text/yaml yaml
-      yml)` works in the same way that `['text/yaml', %w(yaml yml)]` did (and
+      need to be wrapped in another array. This means that `%w(text/yaml yaml yml)` works in the same way that `['text/yaml', %w(yaml yml)]` did (and
       still does).
 
     - Changed `priority_compare` to conform with attributes that no longer