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<!DOCTYPE html>
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<h1>RuboCop Ruby Style Guide - <span style='font-size: 1rem'>Rev: 2022-08-24 58f7c09</span></h1>
<ul style='columns: 3;'>
<li><a href='#introduction'>Introduction</a></li>
<li><a href='#source-code-layout'>Source Code Layout</a></li>
<li><a href='#naming-conventions'>Naming Conventions</a></li>
<li><a href='#flow-of-control'>Flow of Control</a></li>
<li><a href='#exceptions'>Exceptions</a></li>
<li><a href='#assignment-comparison'>Assignment & Comparison</a></li>
<li><a href='#blocks-procs-lambdas'>Blocks, Procs & Lambdas</a></li>
<li><a href='#methods'>Methods</a></li>
<li><a href='#classes-modules'>Classes & Modules</a></li>
<li><a href='#classes-constructors'>Classes: Constructors</a></li>
<li><a href='#comments'>Comments</a></li>
<li><a href='#comment-annotations'>Comment Annotations</a></li>
<li><a href='#magic-comments'>Magic Comments</a></li>
<li><a href='#collections'>Collections</a></li>
<li><a href='#numbers'>Numbers</a></li>
<li><a href='#strings'>Strings</a></li>
<li><a href='#heredocs'>Heredocs</a></li>
<li><a href='#date-time'>Date & Time</a></li>
<li><a href='#regular-expressions'>Regular Expressions</a></li>
<li><a href='#percent-literals'>Percent Literals</a></li>
<li><a href='#metaprogramming'>Metaprogramming</a></li>
<li><a href='#api-documentation'>API Documentation</a></li>
<li><a href='#gemfile-and-gemspec'>Gemfile and Gemspec</a></li>
<li><a href='#misc'>Misc</a></li>
<li><a href='#tools'>Tools</a></li>
<li><a href='#history'>History</a></li>
<li><a href='#sources-of-inspiration'>Sources of Inspiration</a></li>
<li><a href='#contributing'>Contributing</a></li>
<li><a href='#colophon'>Colophon</a></li>
<li><a href='#license'>License</a></li>
<li><a href='#spread-the-word'>Spread the Word</a></li>
</ul>
<div class="sect1">
<h2 id="introduction">Introduction</h2>
<div class="sectionbody">
<div class="quoteblock">
<blockquote>
<div class="paragraph">
<p>Role models are important.</p>
</div>
</blockquote>
<div class="attribution">
— Officer Alex J. Murphy / RoboCop
</div>
</div>
<div class="paragraph">
<p>This Ruby style guide recommends best practices so that real-world Ruby programmers can write code that can be maintained by other real-world Ruby programmers.
A style guide that reflects real-world usage gets used, while a style guide that holds to an ideal that has been rejected by the people it is supposed to help risks not getting used at all - no matter how good it is.</p>
</div>
<div class="paragraph">
<p>The guide is separated into several sections of related guidelines.
We’ve tried to add the rationale behind the guidelines (if it’s omitted we’ve assumed it’s pretty obvious).</p>
</div>
<div class="paragraph">
<p>We didn’t come up with all the guidelines out of nowhere - they are mostly based on the professional experience of the editors, feedback and suggestions from members of the Ruby community and various highly regarded Ruby programming resources, such as <a href="https://pragprog.com/book/ruby4/programming-ruby-1-9-2-0">"Programming Ruby"</a> and <a href="https://www.amazon.com/Ruby-Programming-Language-David-Flanagan/dp/0596516177">"The Ruby Programming Language"</a>.</p>
</div>
<div class="paragraph">
<p>This style guide evolves over time as additional conventions are identified and past conventions are rendered obsolete by changes in Ruby itself.</p>
</div>
<div class="admonitionblock tip">
<table>
<tr>
<td class="icon">
<div class="title">Tip</div>
</td>
<td class="content">
<div class="paragraph">
<p>If you’re into Rails or RSpec you might want to check out the complementary <a href="https://github.com/rubocop/rails-style-guide">Ruby on Rails Style Guide</a> and <a href="https://github.com/rubocop/rspec-style-guide">RSpec Style Guide</a>.</p>
</div>
</td>
</tr>
</table>
</div>
<div class="admonitionblock tip">
<table>
<tr>
<td class="icon">
<div class="title">Tip</div>
</td>
<td class="content">
<a href="https://github.com/rubocop/rubocop">RuboCop</a> is a static code analyzer (linter) and formatter, based on this style guide.
</td>
</tr>
</table>
</div>
<div class="sect2">
<h3 id="guiding-principles">Guiding Principles</h3>
<div class="quoteblock">
<blockquote>
<div class="paragraph">
<p>Programs must be written for people to read, and only incidentally for machines to execute.</p>
</div>
</blockquote>
<div class="attribution">
— Harold Abelson<br>
<cite>Structure and Interpretation of Computer Programs</cite>
</div>
</div>
<div class="paragraph">
<p>It’s common knowledge that code is read much more often than it is written.
The guidelines provided here are intended to improve the readability of code and make it consistent across the wide spectrum of Ruby code.
They are also meant to reflect real-world usage of Ruby instead of a random ideal. When we had to choose between a very established practice
and a subjectively better alternative we’ve opted to recommend the established practice.<sup class="footnote">[<a id="_footnoteref_1" class="footnote" href="#_footnotedef_1" title="View footnote.">1</a>]</sup></p>
</div>
<div class="paragraph">
<p>There are some areas in which there is no clear consensus in the Ruby community regarding a particular style (like string literal quoting, spacing inside hash literals, dot position in multi-line method chaining, etc.).
In such scenarios all popular styles are acknowledged and it’s up to you to pick one and apply it consistently.</p>
</div>
<div class="paragraph">
<p>Ruby had existed for over 15 years by the time
the guide was created, and the language’s flexibility and lack of common standards have contributed to the
creation of numerous styles for just about everything. Rallying people around the cause of community standards
took a lot of time and energy, and we still have a lot of ground to cover.</p>
</div>
<div class="paragraph">
<p>Ruby is famously optimized for programmer happiness. We’d like to believe that this guide is going to help you optimize for maximum
programmer happiness.</p>
</div>
</div>
<div class="sect2">
<h3 id="a-note-about-consistency">A Note about Consistency</h3>
<div class="quoteblock">
<blockquote>
<div class="paragraph">
<p>A foolish consistency is the hobgoblin of little minds, adored by little statesmen and philosophers and divines.</p>
</div>
</blockquote>
<div class="attribution">
— Ralph Waldo Emerson
</div>
</div>
<div class="paragraph">
<p>A style guide is about consistency.
Consistency with this style guide is important.
Consistency within a project is more important.
Consistency within one class or method is the most important.</p>
</div>
<div class="paragraph">
<p>However, know when to be inconsistent — sometimes style guide recommendations just aren’t applicable. When in doubt, use your best judgment.
Look at other examples and decide what looks best. And don’t hesitate to ask!</p>
</div>
<div class="paragraph">
<p>In particular: do not break backwards compatibility just to comply with this guide!</p>
</div>
<div class="paragraph">
<p>Some other good reasons to ignore a particular guideline:</p>
</div>
<div class="ulist">
<ul>
<li>
<p>When applying the guideline would make the code less readable, even for someone who is used to reading code that follows this style guide.</p>
</li>
<li>
<p>To be consistent with surrounding code that also breaks it (maybe for historic reasons) — although this is also an opportunity to clean up someone else’s mess (in true XP style).</p>
</li>
<li>
<p>Because the code in question predates the introduction of the guideline and there is no other reason to be modifying that code.</p>
</li>
<li>
<p>When the code needs to remain compatible with older versions of Ruby that don’t support the feature recommended by the style guide.</p>
</li>
</ul>
</div>
</div>
<div class="sect2">
<h3 id="translations">Translations</h3>
<div class="paragraph">
<p>Translations of the guide are available in the following languages:</p>
</div>
<div class="ulist">
<ul>
<li>
<p><a href="https://github.com/JuanitoFatas/ruby-style-guide/blob/master/README-zhCN.md">Chinese Simplified</a></p>
</li>
<li>
<p><a href="https://github.com/JuanitoFatas/ruby-style-guide/blob/master/README-zhTW.md">Chinese Traditional</a></p>
</li>
<li>
<p><a href="https://github.com/HassanTC/ruby-style-guide/blob/master/README-EgAr.md">Egyptian Arabic</a></p>
</li>
<li>
<p><a href="https://github.com/gauthier-delacroix/ruby-style-guide/blob/master/README-frFR.md">French</a></p>
</li>
<li>
<p><a href="https://github.com/fortissimo1997/ruby-style-guide/blob/japanese/README.ja.md">Japanese</a></p>
</li>
<li>
<p><a href="https://github.com/dalzony/ruby-style-guide/blob/master/README-koKR.md">Korean</a></p>
</li>
<li>
<p><a href="https://github.com/rubensmabueno/ruby-style-guide/blob/master/README-PT-BR.md">Portuguese (pt-BR)</a></p>
</li>
<li>
<p><a href="https://github.com/arbox/ruby-style-guide/blob/master/README-ruRU.md">Russian</a></p>
</li>
<li>
<p><a href="https://github.com/alemohamad/ruby-style-guide/blob/master/README-esLA.md">Spanish</a></p>
</li>
<li>
<p><a href="https://github.com/CQBinh/ruby-style-guide/blob/master/README-viVN.md">Vietnamese</a></p>
</li>
</ul>
</div>
<div class="admonitionblock note">
<table>
<tr>
<td class="icon">
<div class="title">Note</div>
</td>
<td class="content">
These translations are not maintained by our editor team, so their quality
and level of completeness may vary. The translated versions of the guide often
lag behind the upstream English version.
</td>
</tr>
</table>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="source-code-layout">Source Code Layout</h2>
<div class="sectionbody">
<div class="quoteblock">
<blockquote>
<div class="paragraph">
<p>Nearly everybody is convinced that every style but their own is
ugly and unreadable. Leave out the "but their own" and they’re
probably right…​</p>
</div>
</blockquote>
<div class="attribution">
— Jerry Coffin (on indentation)
</div>
</div>
<div class="sect2">
<h3 id="utf-8">Source Encoding</h3>
<div class="paragraph">
<p>Use <code>UTF-8</code> as the source file encoding.</p>
</div>
<div class="admonitionblock tip">
<table>
<tr>
<td class="icon">
<div class="title">Tip</div>
</td>
<td class="content">
UTF-8 has been the default source file encoding since Ruby 2.0.
</td>
</tr>
</table>
</div>
</div>
<div class="sect2">
<h3 id="tabs-or-spaces">Tabs or Spaces?</h3>
<div class="paragraph">
<p>Use only spaces for indentation. No hard tabs.</p>
</div>
</div>
<div class="sect2">
<h3 id="spaces-indentation">Indentation</h3>
<div class="paragraph">
<p>Use two <strong>spaces</strong> per indentation level (aka soft tabs).</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad - four spaces
</span><span class='kw'>def</span> <span class='id identifier rubyid_some_method'>some_method</span>
<span class='id identifier rubyid_do_something'>do_something</span>
<span class='kw'>end</span>
<span class='comment'># good
</span><span class='kw'>def</span> <span class='id identifier rubyid_some_method'>some_method</span>
<span class='id identifier rubyid_do_something'>do_something</span>
<span class='kw'>end</span></code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="max-line-length">Maximum Line Length</h3>
<div class="paragraph">
<p>Limit lines to 80 characters.</p>
</div>
<div class="admonitionblock tip">
<table>
<tr>
<td class="icon">
<div class="title">Tip</div>
</td>
<td class="content">
Most editors and IDEs have configuration options to help you with that.
They would typically highlight lines that exceed the length limit.
</td>
</tr>
</table>
</div>
<div class="sidebarblock">
<div class="content">
<div class="title">Why Bother with 80 characters in a World of Modern Widescreen Displays?</div>
<div class="paragraph">
<p>A lot of people these days feel that a maximum line length of 80 characters is
just a remnant of the past and makes little sense today. After all - modern
displays can easily fit 200+ characters on a single line. Still, there are some
important benefits to be gained from sticking to shorter lines of code.</p>
</div>
<div class="paragraph">
<p>First, and foremost - numerous studies have shown that humans read much faster
vertically and very long lines of text impede the reading process. As noted
earlier, one of the guiding principles of this style guide is to optimize the
code we write for human consumption.</p>
</div>
<div class="paragraph">
<p>Additionally, limiting the required editor window width makes it possible to
have several files open side-by-side, and works well when using code review
tools that present the two versions in adjacent columns.</p>
</div>
<div class="paragraph">
<p>The default wrapping in most tools disrupts the visual structure of the code,
making it more difficult to understand. The limits are chosen to avoid wrapping
in editors with the window width set to 80, even if the tool places a marker
glyph in the final column when wrapping lines. Some web based tools may not
offer dynamic line wrapping at all.</p>
</div>
<div class="paragraph">
<p>Some teams strongly prefer a longer line length. For code maintained exclusively
or primarily by a team that can reach agreement on this issue, it is okay to
increase the line length limit up to 100 characters, or all the way up
to 120 characters. Please, restrain the urge to go beyond 120 characters.</p>
</div>
</div>
</div>
</div>
<div class="sect2">
<h3 id="no-trailing-whitespace">No Trailing Whitespace</h3>
<div class="paragraph">
<p>Avoid trailing whitespace.</p>
</div>
<div class="admonitionblock tip">
<table>
<tr>
<td class="icon">
<div class="title">Tip</div>
</td>
<td class="content">
Most editors and IDEs have configuration options to visualize trailing whitespace and
to remove it automatically on save.
</td>
</tr>
</table>
</div>
</div>
<div class="sect2">
<h3 id="crlf">Line Endings</h3>
<div class="paragraph">
<p>Use Unix-style line endings.<sup class="footnote">[<a id="_footnoteref_2" class="footnote" href="#_footnotedef_2" title="View footnote.">2</a>]</sup></p>
</div>
<div class="admonitionblock tip">
<table>
<tr>
<td class="icon">
<div class="title">Tip</div>
</td>
<td class="content">
<div class="paragraph">
<p>If you’re using Git you might want to add the following configuration setting to protect your project from Windows line endings creeping in:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="highlight"><code class="language-bash" data-lang="bash">$ git config --global core.autocrlf true</code></pre>
</div>
</div>
</td>
</tr>
</table>
</div>
</div>
<div class="sect2">
<h3 id="newline-eof">Should I Terminate Files with a Newline?</h3>
<div class="paragraph">
<p>End each file with a newline.</p>
</div>
<div class="admonitionblock tip">
<table>
<tr>
<td class="icon">
<div class="title">Tip</div>
</td>
<td class="content">
This should be done via editor configuration, not manually.
</td>
</tr>
</table>
</div>
</div>
<div class="sect2">
<h3 id="no-semicolon">Should I Terminate Expressions with <code>;</code>?</h3>
<div class="paragraph">
<p>Don’t use <code>;</code> to terminate statements and expressions.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='id identifier rubyid_puts'>puts</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>foobar</span><span class='tstring_end'>'</span></span><span class='semicolon'>;</span> <span class='comment'># superfluous semicolon
</span>
<span class='comment'># good
</span><span class='id identifier rubyid_puts'>puts</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>foobar</span><span class='tstring_end'>'</span></span></code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="one-expression-per-line">One Expression Per Line</h3>
<div class="paragraph">
<p>Use one expression per line.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='id identifier rubyid_puts'>puts</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>foo</span><span class='tstring_end'>'</span></span><span class='semicolon'>;</span> <span class='id identifier rubyid_puts'>puts</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>bar</span><span class='tstring_end'>'</span></span> <span class='comment'># two expressions on the same line
</span>
<span class='comment'># good
</span><span class='id identifier rubyid_puts'>puts</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>foo</span><span class='tstring_end'>'</span></span>
<span class='id identifier rubyid_puts'>puts</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>bar</span><span class='tstring_end'>'</span></span>
<span class='id identifier rubyid_puts'>puts</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>foo</span><span class='tstring_end'>'</span></span><span class='comma'>,</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>bar</span><span class='tstring_end'>'</span></span> <span class='comment'># this applies to puts in particular</span></code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="spaces-operators">Spaces and Operators</h3>
<div class="paragraph">
<p>Use spaces around operators, after commas, colons and semicolons.
Whitespace might be (mostly) irrelevant to the Ruby interpreter, but its proper use is the key to writing easily readable code.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='id identifier rubyid_sum'>sum</span><span class='op'>=</span><span class='int'>1</span><span class='op'>+</span><span class='int'>2</span>
<span class='id identifier rubyid_a'>a</span><span class='comma'>,</span><span class='id identifier rubyid_b'>b</span><span class='op'>=</span><span class='int'>1</span><span class='comma'>,</span><span class='int'>2</span>
<span class='kw'>class</span> <span class='const'>FooError</span><span class='op'><</span><span class='const'>StandardError</span><span class='semicolon'>;</span><span class='kw'>end</span>
<span class='comment'># good
</span><span class='id identifier rubyid_sum'>sum</span> <span class='op'>=</span> <span class='int'>1</span> <span class='op'>+</span> <span class='int'>2</span>
<span class='id identifier rubyid_a'>a</span><span class='comma'>,</span> <span class='id identifier rubyid_b'>b</span> <span class='op'>=</span> <span class='int'>1</span><span class='comma'>,</span> <span class='int'>2</span>
<span class='kw'>class</span> <span class='const'>FooError</span> <span class='op'><</span> <span class='const'>StandardError</span><span class='semicolon'>;</span> <span class='kw'>end</span></code></pre>
</div>
</div>
<div class="paragraph">
<p>There are a few exceptions:</p>
</div>
<div class="ulist">
<ul>
<li>
<p>Exponent operator:</p>
</li>
</ul>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='id identifier rubyid_e'>e</span> <span class='op'>=</span> <span class='const'>M</span> <span class='op'>*</span> <span class='id identifier rubyid_c'>c</span> <span class='op'>**</span> <span class='int'>2</span>
<span class='comment'># good
</span><span class='id identifier rubyid_e'>e</span> <span class='op'>=</span> <span class='const'>M</span> <span class='op'>*</span> <span class='id identifier rubyid_c'>c</span><span class='op'>**</span><span class='int'>2</span></code></pre>
</div>
</div>
<div class="ulist">
<ul>
<li>
<p>Slash in rational literals:</p>
</li>
</ul>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='id identifier rubyid_o_scale'>o_scale</span> <span class='op'>=</span> <span class='int'>1</span> <span class='op'>/</span> <span class='rational'>48r</span>
<span class='comment'># good
</span><span class='id identifier rubyid_o_scale'>o_scale</span> <span class='op'>=</span> <span class='int'>1</span><span class='op'>/</span><span class='rational'>48r</span></code></pre>
</div>
</div>
<div class="ulist">
<ul>
<li>
<p>Safe navigation operator:</p>
</li>
</ul>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='id identifier rubyid_foo'>foo</span> <span class='op'>&.</span> <span class='id identifier rubyid_bar'>bar</span>
<span class='id identifier rubyid_foo'>foo</span> <span class='op'>&.</span><span class='id identifier rubyid_bar'>bar</span>
<span class='id identifier rubyid_foo'>foo</span><span class='op'>&.</span> <span class='id identifier rubyid_bar'>bar</span>
<span class='comment'># good
</span><span class='id identifier rubyid_foo'>foo</span><span class='op'>&.</span><span class='id identifier rubyid_bar'>bar</span></code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="spaces-braces">Spaces and Braces</h3>
<div class="paragraph">
<p>No spaces after <code>(</code>, <code>[</code> or before <code>]</code>, <code>)</code>.
Use spaces around <code>{</code> and before <code>}</code>.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='id identifier rubyid_some'>some</span>( <span class='id identifier rubyid_arg'>arg</span> ).<span class='id identifier rubyid_other'>other</span>
[ <span class='int'>1</span><span class='comma'>,</span> <span class='int'>2</span><span class='comma'>,</span> <span class='int'>3</span> ].<span class='id identifier rubyid_each'>each</span>{<span class='op'>|</span><span class='id identifier rubyid_e'>e</span><span class='op'>|</span> <span class='id identifier rubyid_puts'>puts</span> <span class='id identifier rubyid_e'>e</span>}
<span class='comment'># good
</span><span class='id identifier rubyid_some'>some</span>(<span class='id identifier rubyid_arg'>arg</span>).<span class='id identifier rubyid_other'>other</span>
[<span class='int'>1</span><span class='comma'>,</span> <span class='int'>2</span><span class='comma'>,</span> <span class='int'>3</span>].<span class='id identifier rubyid_each'>each</span> { <span class='op'>|</span><span class='id identifier rubyid_e'>e</span><span class='op'>|</span> <span class='id identifier rubyid_puts'>puts</span> <span class='id identifier rubyid_e'>e</span> }</code></pre>
</div>
</div>
<div class="paragraph">
<p><code>{</code> and <code>}</code> deserve a bit of clarification, since they are used for block and hash literals, as well as string interpolation.</p>
</div>
<div class="paragraph">
<p>For hash literals two styles are considered acceptable.
The first variant is slightly more readable (and arguably more popular in the Ruby community in general).
The second variant has the advantage of adding visual difference between block and hash literals.
Whichever one you pick - apply it consistently.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># good - space after { and before }
</span>{ <span class='label'>one:</span> <span class='int'>1</span><span class='comma'>,</span> <span class='label'>two:</span> <span class='int'>2</span> }
<span class='comment'># good - no space after { and before }
</span>{<span class='label'>one:</span> <span class='int'>1</span><span class='comma'>,</span> <span class='label'>two:</span> <span class='int'>2</span>}</code></pre>
</div>
</div>
<div class="paragraph">
<p>With interpolated expressions, there should be no padded-spacing inside the braces.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='tstring'><span class='tstring_beg'>"</span><span class='tstring_content'>From: </span><span class='embexpr_beg'>#{</span> <span class='id identifier rubyid_user'>user</span>.<span class='id identifier rubyid_first_name'>first_name</span> <span class='embexpr_end'>}</span><span class='tstring_content'>, </span><span class='embexpr_beg'>#{</span> <span class='id identifier rubyid_user'>user</span>.<span class='id identifier rubyid_last_name'>last_name</span> <span class='embexpr_end'>}</span><span class='tstring_end'>"</span></span>
<span class='comment'># good
</span><span class='tstring'><span class='tstring_beg'>"</span><span class='tstring_content'>From: </span><span class='embexpr_beg'>#{</span><span class='id identifier rubyid_user'>user</span>.<span class='id identifier rubyid_first_name'>first_name</span><span class='embexpr_end'>}</span><span class='tstring_content'>, </span><span class='embexpr_beg'>#{</span><span class='id identifier rubyid_user'>user</span>.<span class='id identifier rubyid_last_name'>last_name</span><span class='embexpr_end'>}</span><span class='tstring_end'>"</span></span></code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="no-space-bang">No Space after Bang</h3>
<div class="paragraph">
<p>No space after <code>!</code>.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='op'>!</span> <span class='id identifier rubyid_something'>something</span>
<span class='comment'># good
</span><span class='op'>!</span><span class='id identifier rubyid_something'>something</span></code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="no-space-inside-range-literals">No Space inside Range Literals</h3>
<div class="paragraph">
<p>No space inside range literals.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='int'>1</span> <span class='op'>..</span> <span class='int'>3</span>
<span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>a</span><span class='tstring_end'>'</span></span> <span class='op'>...</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>z</span><span class='tstring_end'>'</span></span>
<span class='comment'># good
</span><span class='int'>1</span><span class='op'>..</span><span class='int'>3</span>
<span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>a</span><span class='tstring_end'>'</span></span><span class='op'>...</span><span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>z</span><span class='tstring_end'>'</span></span></code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="indent-when-to-case">Indent <code>when</code> to <code>case</code></h3>
<div class="paragraph">
<p>Indent <code>when</code> as deep as <code>case</code>.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='kw'>case</span>
<span class='kw'>when</span> <span class='id identifier rubyid_song'>song</span>.<span class='id identifier rubyid_name'>name</span> <span class='op'>==</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Misty</span><span class='tstring_end'>'</span></span>
<span class='id identifier rubyid_puts'>puts</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Not again!</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='id identifier rubyid_song'>song</span>.<span class='id identifier rubyid_duration'>duration</span> <span class='op'>></span> <span class='int'>120</span>
<span class='id identifier rubyid_puts'>puts</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Too long!</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='const'>Time</span>.<span class='id identifier rubyid_now'>now</span>.<span class='id identifier rubyid_hour'>hour</span> <span class='op'>></span> <span class='int'>21</span>
<span class='id identifier rubyid_puts'>puts</span> <span class='tstring'><span class='tstring_beg'>"</span><span class='tstring_content'>It's too late</span><span class='tstring_end'>"</span></span>
<span class='kw'>else</span>
<span class='id identifier rubyid_song'>song</span>.<span class='id identifier rubyid_play'>play</span>
<span class='kw'>end</span>
<span class='comment'># good
</span><span class='kw'>case</span>
<span class='kw'>when</span> <span class='id identifier rubyid_song'>song</span>.<span class='id identifier rubyid_name'>name</span> <span class='op'>==</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Misty</span><span class='tstring_end'>'</span></span>
<span class='id identifier rubyid_puts'>puts</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Not again!</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='id identifier rubyid_song'>song</span>.<span class='id identifier rubyid_duration'>duration</span> <span class='op'>></span> <span class='int'>120</span>
<span class='id identifier rubyid_puts'>puts</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Too long!</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='const'>Time</span>.<span class='id identifier rubyid_now'>now</span>.<span class='id identifier rubyid_hour'>hour</span> <span class='op'>></span> <span class='int'>21</span>
<span class='id identifier rubyid_puts'>puts</span> <span class='tstring'><span class='tstring_beg'>"</span><span class='tstring_content'>It's too late</span><span class='tstring_end'>"</span></span>
<span class='kw'>else</span>
<span class='id identifier rubyid_song'>song</span>.<span class='id identifier rubyid_play'>play</span>
<span class='kw'>end</span></code></pre>
</div>
</div>
<div class="sidebarblock">
<div class="content">
<div class="title">A Bit of History</div>
<div class="paragraph">
<p>This is the style established in both "The Ruby Programming Language" and "Programming Ruby".
Historically it is derived from the fact that <code>case</code> and <code>switch</code> statements are not blocks, hence should not be indented, and the <code>when</code> and <code>else</code> keywords are labels (compiled in the C language, they are literally labels for <code>JMP</code> calls).</p>
</div>
</div>
</div>
</div>
<div class="sect2">
<h3 id="indent-conditional-assignment">Indent Conditional Assignment</h3>
<div class="paragraph">
<p>When assigning the result of a conditional expression to a variable, preserve the usual alignment of its branches.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad - pretty convoluted
</span><span class='id identifier rubyid_kind'>kind</span> <span class='op'>=</span> <span class='kw'>case</span> <span class='id identifier rubyid_year'>year</span>
<span class='kw'>when</span> <span class='int'>1850</span><span class='op'>..</span><span class='int'>1889</span> <span class='kw'>then</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Blues</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='int'>1890</span><span class='op'>..</span><span class='int'>1909</span> <span class='kw'>then</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Ragtime</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='int'>1910</span><span class='op'>..</span><span class='int'>1929</span> <span class='kw'>then</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>New Orleans Jazz</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='int'>1930</span><span class='op'>..</span><span class='int'>1939</span> <span class='kw'>then</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Swing</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='int'>1940</span><span class='op'>..</span><span class='int'>1950</span> <span class='kw'>then</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Bebop</span><span class='tstring_end'>'</span></span>
<span class='kw'>else</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Jazz</span><span class='tstring_end'>'</span></span>
<span class='kw'>end</span>
<span class='id identifier rubyid_result'>result</span> <span class='op'>=</span> <span class='kw'>if</span> <span class='id identifier rubyid_some_cond'>some_cond</span>
<span class='id identifier rubyid_calc_something'>calc_something</span>
<span class='kw'>else</span>
<span class='id identifier rubyid_calc_something_else'>calc_something_else</span>
<span class='kw'>end</span>
<span class='comment'># good - it's apparent what's going on
</span><span class='id identifier rubyid_kind'>kind</span> <span class='op'>=</span> <span class='kw'>case</span> <span class='id identifier rubyid_year'>year</span>
<span class='kw'>when</span> <span class='int'>1850</span><span class='op'>..</span><span class='int'>1889</span> <span class='kw'>then</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Blues</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='int'>1890</span><span class='op'>..</span><span class='int'>1909</span> <span class='kw'>then</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Ragtime</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='int'>1910</span><span class='op'>..</span><span class='int'>1929</span> <span class='kw'>then</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>New Orleans Jazz</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='int'>1930</span><span class='op'>..</span><span class='int'>1939</span> <span class='kw'>then</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Swing</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='int'>1940</span><span class='op'>..</span><span class='int'>1950</span> <span class='kw'>then</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Bebop</span><span class='tstring_end'>'</span></span>
<span class='kw'>else</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Jazz</span><span class='tstring_end'>'</span></span>
<span class='kw'>end</span>
<span class='id identifier rubyid_result'>result</span> <span class='op'>=</span> <span class='kw'>if</span> <span class='id identifier rubyid_some_cond'>some_cond</span>
<span class='id identifier rubyid_calc_something'>calc_something</span>
<span class='kw'>else</span>
<span class='id identifier rubyid_calc_something_else'>calc_something_else</span>
<span class='kw'>end</span>
<span class='comment'># good (and a bit more width efficient)
</span><span class='id identifier rubyid_kind'>kind</span> <span class='op'>=</span>
<span class='kw'>case</span> <span class='id identifier rubyid_year'>year</span>
<span class='kw'>when</span> <span class='int'>1850</span><span class='op'>..</span><span class='int'>1889</span> <span class='kw'>then</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Blues</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='int'>1890</span><span class='op'>..</span><span class='int'>1909</span> <span class='kw'>then</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Ragtime</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='int'>1910</span><span class='op'>..</span><span class='int'>1929</span> <span class='kw'>then</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>New Orleans Jazz</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='int'>1930</span><span class='op'>..</span><span class='int'>1939</span> <span class='kw'>then</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Swing</span><span class='tstring_end'>'</span></span>
<span class='kw'>when</span> <span class='int'>1940</span><span class='op'>..</span><span class='int'>1950</span> <span class='kw'>then</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Bebop</span><span class='tstring_end'>'</span></span>
<span class='kw'>else</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>Jazz</span><span class='tstring_end'>'</span></span>
<span class='kw'>end</span>
<span class='id identifier rubyid_result'>result</span> <span class='op'>=</span>
<span class='kw'>if</span> <span class='id identifier rubyid_some_cond'>some_cond</span>
<span class='id identifier rubyid_calc_something'>calc_something</span>
<span class='kw'>else</span>
<span class='id identifier rubyid_calc_something_else'>calc_something_else</span>
<span class='kw'>end</span></code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="empty-lines-between-methods">Empty Lines between Methods</h3>
<div class="paragraph">
<p>Use empty lines between method definitions and also to break up methods into logical paragraphs internally.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='kw'>def</span> <span class='id identifier rubyid_some_method'>some_method</span>
<span class='id identifier rubyid_data'>data</span> <span class='op'>=</span> <span class='id identifier rubyid_initialize'>initialize</span>(<span class='id identifier rubyid_options'>options</span>)
<span class='id identifier rubyid_data'>data</span>.<span class='id identifier rubyid_manipulate!'>manipulate!</span>
<span class='id identifier rubyid_data'>data</span>.<span class='id identifier rubyid_result'>result</span>
<span class='kw'>end</span>
<span class='kw'>def</span> <span class='id identifier rubyid_some_other_method'>some_other_method</span>
<span class='id identifier rubyid_result'>result</span>
<span class='kw'>end</span>
<span class='comment'># good
</span><span class='kw'>def</span> <span class='id identifier rubyid_some_method'>some_method</span>
<span class='id identifier rubyid_data'>data</span> <span class='op'>=</span> <span class='id identifier rubyid_initialize'>initialize</span>(<span class='id identifier rubyid_options'>options</span>)
<span class='id identifier rubyid_data'>data</span>.<span class='id identifier rubyid_manipulate!'>manipulate!</span>
<span class='id identifier rubyid_data'>data</span>.<span class='id identifier rubyid_result'>result</span>
<span class='kw'>end</span>
<span class='kw'>def</span> <span class='id identifier rubyid_some_other_method'>some_other_method</span>
<span class='id identifier rubyid_result'>result</span>
<span class='kw'>end</span></code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="two-or-more-empty-lines">Two or More Empty Lines</h3>
<div class="paragraph">
<p>Don’t use several empty lines in a row.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad - It has two empty lines.
</span><span class='id identifier rubyid_some_method'>some_method</span>
<span class='id identifier rubyid_some_method'>some_method</span>
<span class='comment'># good
</span><span class='id identifier rubyid_some_method'>some_method</span>
<span class='id identifier rubyid_some_method'>some_method</span></code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="empty-lines-around-attribute-accessor">Empty Lines around Attribute Accessor</h3>
<div class="paragraph">
<p>Use empty lines around attribute accessor.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='kw'>class</span> <span class='const'>Foo</span>
<span class='id identifier rubyid_attr_reader'>attr_reader</span> <span class='symbeg'>:</span><span class='id identifier rubyid_foo'>foo</span>
<span class='kw'>def</span> <span class='id identifier rubyid_foo'>foo</span>
<span class='comment'># do something...
</span> <span class='kw'>end</span>
<span class='kw'>end</span>
<span class='comment'># good
</span><span class='kw'>class</span> <span class='const'>Foo</span>
<span class='id identifier rubyid_attr_reader'>attr_reader</span> <span class='symbeg'>:</span><span class='id identifier rubyid_foo'>foo</span>
<span class='kw'>def</span> <span class='id identifier rubyid_foo'>foo</span>
<span class='comment'># do something...
</span> <span class='kw'>end</span>
<span class='kw'>end</span></code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="empty-lines-around-access-modifier">Empty Lines around Access Modifier</h3>
<div class="paragraph">
<p>Use empty lines around access modifier.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='kw'>class</span> <span class='const'>Foo</span>
<span class='kw'>def</span> <span class='id identifier rubyid_bar'>bar</span><span class='semicolon'>;</span> <span class='kw'>end</span>
<span class='id identifier rubyid_private'>private</span>
<span class='kw'>def</span> <span class='id identifier rubyid_baz'>baz</span><span class='semicolon'>;</span> <span class='kw'>end</span>
<span class='kw'>end</span>
<span class='comment'># good
</span><span class='kw'>class</span> <span class='const'>Foo</span>
<span class='kw'>def</span> <span class='id identifier rubyid_bar'>bar</span><span class='semicolon'>;</span> <span class='kw'>end</span>
<span class='id identifier rubyid_private'>private</span>
<span class='kw'>def</span> <span class='id identifier rubyid_baz'>baz</span><span class='semicolon'>;</span> <span class='kw'>end</span>
<span class='kw'>end</span></code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="empty-lines-around-bodies">Empty Lines around Bodies</h3>
<div class="paragraph">
<p>Don’t use empty lines around method, class, module, block bodies.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='kw'>class</span> <span class='const'>Foo</span>
<span class='kw'>def</span> <span class='id identifier rubyid_foo'>foo</span>
<span class='kw'>begin</span>
<span class='id identifier rubyid_do_something'>do_something</span> <span class='kw'>do</span>
<span class='id identifier rubyid_something'>something</span>
<span class='kw'>end</span>
<span class='kw'>rescue</span>
<span class='id identifier rubyid_something'>something</span>
<span class='kw'>end</span>
<span class='kw'>true</span>
<span class='kw'>end</span>
<span class='kw'>end</span>
<span class='comment'># good
</span><span class='kw'>class</span> <span class='const'>Foo</span>
<span class='kw'>def</span> <span class='id identifier rubyid_foo'>foo</span>
<span class='kw'>begin</span>
<span class='id identifier rubyid_do_something'>do_something</span> <span class='kw'>do</span>
<span class='id identifier rubyid_something'>something</span>
<span class='kw'>end</span>
<span class='kw'>rescue</span>
<span class='id identifier rubyid_something'>something</span>
<span class='kw'>end</span>
<span class='kw'>end</span>
<span class='kw'>end</span></code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="no-trailing-params-comma">Trailing Comma in Method Arguments</h3>
<div class="paragraph">
<p>Avoid comma after the last parameter in a method call, especially when the parameters are not on separate lines.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad - easier to move/add/remove parameters, but still not preferred
</span><span class='id identifier rubyid_some_method'>some_method</span>(
<span class='id identifier rubyid_size'>size</span><span class='comma'>,</span>
<span class='id identifier rubyid_count'>count</span><span class='comma'>,</span>
<span class='id identifier rubyid_color'>color</span><span class='comma'>,</span>
)
<span class='comment'># bad
</span><span class='id identifier rubyid_some_method'>some_method</span>(<span class='id identifier rubyid_size'>size</span><span class='comma'>,</span> <span class='id identifier rubyid_count'>count</span><span class='comma'>,</span> <span class='id identifier rubyid_color'>color</span><span class='comma'>,</span> )
<span class='comment'># good
</span><span class='id identifier rubyid_some_method'>some_method</span>(<span class='id identifier rubyid_size'>size</span><span class='comma'>,</span> <span class='id identifier rubyid_count'>count</span><span class='comma'>,</span> <span class='id identifier rubyid_color'>color</span>)</code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="spaces-around-equals">Spaces around Equals</h3>
<div class="paragraph">
<p>Use spaces around the <code>=</code> operator when assigning default values to method parameters:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad
</span><span class='kw'>def</span> <span class='id identifier rubyid_some_method'>some_method</span>(<span class='id identifier rubyid_arg1'>arg1</span><span class='op'>=</span><span class='symbeg'>:</span><span class='id identifier rubyid_default'>default</span><span class='comma'>,</span> <span class='id identifier rubyid_arg2'>arg2</span><span class='op'>=</span><span class='kw'>nil</span><span class='comma'>,</span> <span class='id identifier rubyid_arg3'>arg3</span><span class='op'>=</span>[])
<span class='comment'># do something...
</span><span class='kw'>end</span>
<span class='comment'># good
</span><span class='kw'>def</span> <span class='id identifier rubyid_some_method'>some_method</span>(<span class='id identifier rubyid_arg1'>arg1</span> <span class='op'>=</span> <span class='symbeg'>:</span><span class='id identifier rubyid_default'>default</span><span class='comma'>,</span> <span class='id identifier rubyid_arg2'>arg2</span> <span class='op'>=</span> <span class='kw'>nil</span><span class='comma'>,</span> <span class='id identifier rubyid_arg3'>arg3</span> <span class='op'>=</span> [])
<span class='comment'># do something...
</span><span class='kw'>end</span></code></pre>
</div>
</div>
<div class="paragraph">
<p>While several Ruby books suggest the first style, the second is much more
prominent in practice (and arguably a bit more readable).</p>
</div>
</div>
<div class="sect2">
<h3 id="no-trailing-backslash">Line Continuation in Expressions</h3>
<div class="paragraph">
<p>Avoid line continuation with <code>\</code> where not required.
In practice, avoid using line continuations for anything but string concatenation.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad (\ is not needed here)
</span><span class='id identifier rubyid_result'>result</span> <span class='op'>=</span> <span class='int'>1</span> <span class='op'>-</span> \
<span class='int'>2</span>
<span class='comment'># bad (\ is required, but still ugly as hell)
</span><span class='id identifier rubyid_result'>result</span> <span class='op'>=</span> <span class='int'>1</span> \
<span class='op'>-</span> <span class='int'>2</span>
<span class='comment'># good
</span><span class='id identifier rubyid_result'>result</span> <span class='op'>=</span> <span class='int'>1</span> <span class='op'>-</span>
<span class='int'>2</span>
<span class='id identifier rubyid_long_string'>long_string</span> <span class='op'>=</span> <span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'>First part of the long string</span><span class='tstring_end'>'</span></span> \
<span class='tstring'><span class='tstring_beg'>'</span><span class='tstring_content'> and second part of the long string</span><span class='tstring_end'>'</span></span></code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="consistent-multi-line-chains">Multi-line Method Chains</h3>
<div class="paragraph">
<p>Adopt a consistent multi-line method chaining style.
There are two popular styles in the Ruby community, both of which are considered good - leading <code>.</code> and trailing <code>.</code>.</p>
</div>
<div class="sect3">
<h4 id="leading-dot-in-multi-line-chains">Leading <code>.</code></h4>
<div class="paragraph">
<p>When continuing a chained method call on another line, keep the <code>.</code> on the second line.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad - need to consult first line to understand second line
</span><span class='id identifier rubyid_one'>one</span>.<span class='id identifier rubyid_two'>two</span>.<span class='id identifier rubyid_three'>three</span>.
<span class='id identifier rubyid_four'>four</span>
<span class='comment'># good - it's immediately clear what's going on the second line
</span><span class='id identifier rubyid_one'>one</span>.<span class='id identifier rubyid_two'>two</span>.<span class='id identifier rubyid_three'>three</span>
.<span class='id identifier rubyid_four'>four</span></code></pre>
</div>
</div>
</div>
<div class="sect3">
<h4 id="trailing-dot-in-multi-line-chains">Trailing <code>.</code></h4>
<div class="paragraph">
<p>When continuing a chained method call on another line, include the <code>.</code> on the first line to indicate that the expression continues.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="code ruby"><code class="ruby"><span class='comment'># bad - need to read ahead to the second line to know that the chain continues
</span><span class='id identifier rubyid_one'>one</span>.<span class='id identifier rubyid_two'>two</span>.<span class='id identifier rubyid_three'>three</span>
.<span class='id identifier rubyid_four'>four</span>