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See <code>vignette("rd-other")</code> for documenting other types of objects and <code>vignette("reuse")</code> for reusing documentation across topics.</p> <div id="basics" class="section level2"> <h2>Basics</h2> <p>A roxygen <strong>block</strong> is a sequence of lines starting with <code>#'</code> (optionally preceded by white space).</p> <p>The first lines of the block is called the <strong>introduction</strong> and forms the title, description, and details, as described below. The introduction continues until the first <strong>tag</strong>.</p> <p>Tags start with <code>@</code>, like <code>@details</code> or <code>@param</code>. Tags must appear at the beginning of a line and their content extends to the start of the next tag or the end of the block. Text within the description or tags can be formatted using Markdown or <code>Rd</code> commands; see <code>vignette("rd-formatting")</code> for details.</p> <p>A block ends when it hits R code, usually a function or object assignment. Blocks ignore empty lines, including lines made up of non-roxygen comments. If you need to separate two blocks, use <code>NULL</code>.</p> <p>If you want to use roxygen2 documentation tags without generating an <code>.Rd</code> file, you can use <code>@noRd</code> to suppress file generation for a given topic. This is useful if you want to use roxygen2 conventions for documenting an internal function; only people reading the source doc will be able to read the docs.</p> </div> <div id="the-introduction" class="section level2"> <h2>The introduction</h2> <p>Each documentation block starts with some text which defines the title, the description, and the details. Here’s an example showing what the documentation for <code>sum()</code> might look like if it had been written with roxygen:</p> <div class="sourceCode" id="cb1"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb1-1"><a href="#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="co">#' Sum of vector elements</span></span> <span id="cb1-2"><a href="#cb1-2" aria-hidden="true" tabindex="-1"></a><span class="co">#'</span></span> <span id="cb1-3"><a href="#cb1-3" aria-hidden="true" tabindex="-1"></a><span class="co">#' `sum` returns the sum of all the values present in its arguments.</span></span> <span id="cb1-4"><a href="#cb1-4" aria-hidden="true" tabindex="-1"></a><span class="co">#'</span></span> <span id="cb1-5"><a href="#cb1-5" aria-hidden="true" tabindex="-1"></a><span class="co">#' This is a generic function: methods can be defined for it directly</span></span> <span id="cb1-6"><a href="#cb1-6" aria-hidden="true" tabindex="-1"></a><span class="co">#' or via the [Summary()] group generic. For this to work properly,</span></span> <span id="cb1-7"><a href="#cb1-7" aria-hidden="true" tabindex="-1"></a><span class="co">#' the arguments `...` should be unnamed, and dispatch is on the</span></span> <span id="cb1-8"><a href="#cb1-8" aria-hidden="true" tabindex="-1"></a><span class="co">#' first argument.</span></span> <span id="cb1-9"><a href="#cb1-9" aria-hidden="true" tabindex="-1"></a>sum <span class="ot"><-</span> <span class="cf">function</span>(..., <span class="at">na.rm =</span> <span class="cn">TRUE</span>) {}</span></code></pre></div> <p>This introductory block is broken up as follows:</p> <ul> <li><p>The first sentence is the <strong>title</strong>: that’s what you see when you look at <code>help(package = mypackage)</code> and is shown at the top of each help file. It should generally fit on one line, be written in sentence case, and not end in a full stop.</p></li> <li><p>The second paragraph is the <strong>description</strong>: this comes first in the documentation and should briefly describe what the function does.</p></li> <li><p>The third and subsequent paragraphs go into the <strong>details</strong>: this is a (often long) section that comes after the argument description and should provide any other important details of how the function operates. The details are optional.</p></li> </ul> <p>You can also use explicit <code>@title</code>, <code>@description</code>, and <code>@details</code> tags. This is unnecessary unless you want to have a multi-paragraph description, bulleted list, or other more exotic structure.</p> <div class="sourceCode" id="cb2"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb2-1"><a href="#cb2-1" aria-hidden="true" tabindex="-1"></a><span class="co">#' Sum of vector elements</span></span> <span id="cb2-2"><a href="#cb2-2" aria-hidden="true" tabindex="-1"></a><span class="co">#' </span></span> <span id="cb2-3"><a href="#cb2-3" aria-hidden="true" tabindex="-1"></a><span class="co">#' @description</span></span> <span id="cb2-4"><a href="#cb2-4" aria-hidden="true" tabindex="-1"></a><span class="co">#' `sum` returns the sum of all the values present in its arguments.</span></span> <span id="cb2-5"><a href="#cb2-5" aria-hidden="true" tabindex="-1"></a><span class="co">#'</span></span> <span id="cb2-6"><a href="#cb2-6" aria-hidden="true" tabindex="-1"></a><span class="co">#' @details</span></span> <span id="cb2-7"><a href="#cb2-7" aria-hidden="true" tabindex="-1"></a><span class="co">#' This is a generic function: methods can be defined for it directly</span></span> <span id="cb2-8"><a href="#cb2-8" aria-hidden="true" tabindex="-1"></a><span class="co">#' or via the [Summary()] group generic. For this to work properly,</span></span> <span id="cb2-9"><a href="#cb2-9" aria-hidden="true" tabindex="-1"></a><span class="co">#' the arguments `...` should be unnamed, and dispatch is on the</span></span> <span id="cb2-10"><a href="#cb2-10" aria-hidden="true" tabindex="-1"></a><span class="co">#' first argument.</span></span></code></pre></div> </div> <div id="functions" class="section level2"> <h2>Functions</h2> <p>Functions are the mostly commonly documented objects. Functions require three tags: <code>@param</code>, <code>@returns</code>, and <code>@examples</code>.</p> <div id="inputs" class="section level3"> <h3>Inputs</h3> <p>Use <code>@param name description</code> to describe each input to the function. The description should provide a succinct summary of parameter type (e.g. a string, a numeric vector), and if not obvious from the name, what the parameter does. The description is a sentence so should start with a capital letter and end with a full stop. It can span multiple lines (or even paragraphs) if necessary. All parameters must be documented.</p> <p>If two or more arguments are tightly coupled, you can document them in one place by separating the names with commas (no spaces). For example, to document both <code>x</code> and <code>y</code>, you can say <code>@param x,y Numeric vectors</code>.</p> </div> <div id="outputs" class="section level3"> <h3>Outputs</h3> <p><code>@returns description</code> describes the output from the function. Briefly describe the type/shape of the output, not the details.</p> <p>All functions must have a documented return value for initial CRAN submission.</p> </div> <div id="examples" class="section level3"> <h3>Examples</h3> <p><code>@examples</code> provides executable R code showing how to use the function in practice. This is a very important part of the documentation because many people look at the examples before reading anything. Example code must work without errors as it is run automatically as part of <code>R CMD check</code>.</p> <p>For the purpose of illustration, it’s often useful to include code that causes an error. You can do this by wrapping the code in <code>try()</code> or using <code>\dontrun{}</code> to exclude from the executed example code.</p> <p>For finer control, you can use <code>@examplesIf</code>:</p> <div class="sourceCode" id="cb3"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb3-1"><a href="#cb3-1" aria-hidden="true" tabindex="-1"></a><span class="co">#' @examplesIf interactive()</span></span> <span id="cb3-2"><a href="#cb3-2" aria-hidden="true" tabindex="-1"></a><span class="co">#' browseURL("https://roxygen2.r-lib.org")</span></span></code></pre></div> <p>This generates</p> <pre><code>\examples{ \dontshow{if (interactive() (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf} gh_organizations(since = 42) \dontshow{\}) # examplesIf} }</code></pre> <p>This way, the code evaluating whether the example can be run is not shown to users reading the help, but it still prevents R CMD check failures.</p> <p>Instead of including examples directly in the documentation, you can put them in separate files and use <code>@example path/relative/to/package/root</code> to insert them into the documentation.</p> <p>All functions must have a documented return value for initial CRAN submission.</p> </div> <div id="usage" class="section level3"> <h3>Usage</h3> <p>In most case, the function usage (which appears beneath the description in the generates docs) will be automatically derived from the function specification. For the cases where it is not, please <a href="https://github.com/r-lib/roxygen2/issues">file an issue</a> and use <code>@usage</code> to override the default with you want. If you want to suppress the usage altogether (which is sometimes useful for internal or deprecated functions), you can use <code>@usage NULL</code>.</p> </div> </div> <!-- code folding --> <!-- dynamically load mathjax for compatibility with self-contained --> <script> (function () { var script = document.createElement("script"); script.type = "text/javascript"; script.src = "https://mathjax.rstudio.com/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML"; document.getElementsByTagName("head")[0].appendChild(script); })(); </script> </body> </html>