In a previous post we learned how to include parts of a document in the generated output. The included parts are defined using tags. The start of a tag is defined in a comment with the format tag::_tagName_[] and the end has the format end::_tagName_[]. Next we must use the tags attribute for the include macro followed by the tagName. If we don’t want to include a tag we must prefix it with an exclamation mark (!).

Document attributes in Asciidoctor are very powerful. We can assign values to a document attributes and reference the attribute name in our document enclosed between curly braces. Asciidoctor will fill in the value when the document is transformed. Instead of a plain value we can also use styling markup in the document attribute definition. We must use the passthrough macro and allow for quote substitution.

In the following example document we define three document attributes: cl-added, cl-updated and cl-changed. We use the passthrough macro, quotes substation to assign CSS classes:

Spring REST Docs is a project to document a RESTful API using tests. The tests are used to invoke real REST calls on the application and to generate Asciidoctor markup snippets. We can use the generated snippets in an Asciidoctor document with documentation about our API. We can use Spring REST Docs to document a REST API we create using Micronaut.

First we must change our build file and include the Asciidoctor plugin and add dependencies to Spring REST Docs. The following example Gradle build file adds the Gradle Asciidoctor plugin, Spring REST Docs dependencies and configures the test and asciidoctor tasks. Spring REST Docs supports three different web clients to invoke the REST API of our application: Spring MockMVC, Spring Webflux WebTestClient and REST Assured. We use REST Assured 3, because it has little dependencies on other frameworks (like Spring).

With the Asciidoctor diagram extension we can include diagrams that are written in plain text. For example PlantUML or Ditaa diagrams. The extension offers a block processor where we include the diagram definitions in our Asciidoctor document. But there is also a block macro processor. With the block macro processor we can refer to an external file. The file is processed and the resulting image is in our output document.

In the following example we see how to use the block macro for a Ditaa diagram:

Normally if we type an URL in Asciidoctor that starts with a scheme Asciidoctor knows about, the URL is turned into a hyperlink. The following schemes are recognized by Asciidoctor:

With Asciidoctor markup we can position images in our document. We can even float images, so text can next to an image, inside only below or about the image. We can also define multiple images to float, so the images are displayed on the same line next to each other. Any text that follows these images is also displayed next to the images. If we want only to have floating images, but the text starting under the images we can place the images inside an open block and assign the block the role float-group.

In the next example we first define three images that all have roles to float left. In the second part we group these images using the role float-group, so the text will not be displayed next to the images, but under the images:

In a previous post we learned how to use data in CSV and DSV format. Recently we can also include tab separated values (TSV) in a Asciidoctor table. We must set the table attribute format to the value tsv. The data can be inside the document, but also defined in an external file which we add with the include macro.

In the following example markup we have a table with inline tab separated values. A second table includes an external file with tab delimited values:

When we write a list in Asciidoctor we can simply create a list item by starting the line with a dot (.). To create a another list item we simply start a new line with a dot (.). But what if we want to add a list item with multiple paragraphs, or text and a source code block element. We can use the list item continuation (+) to indicate to Asciidoctor we want to keep these together for a single list item.

In the following example we have a list in Asciidoctor markup. The second list item has multiple paragraphs , the third item has an extra admonition block and the fourth item contains a source code block:

Defining tables in Asciidoctor is very easy. The start and end of the table are defined by |===. But if we want to add a new table to a table cell we cannot use the same syntax. To define a nested table we must replace the | separator with !. So instead of |=== to indicate the table boundaries we use !===. Also the cell separators are now ! instead of |. Finally we must make sure the table cell or column supports Asciidoc markup, so the table is properly created. We must configure the cell or column with a so the nested table is created.

In the following example Asciidoctor markup we have a simple table with a nested table in the second column and row. Notice we can still apply all table configuration to the nested table as well:

Adding a block title in Asciidoctor is easily done by adding a line at the top of the block that starts with a dot (.). The text following the dot is then used as the title of the block. But if the text of the title itself starts with a dot (.) Asciidoctor get’s confused. For example if we want to use a filename that starts with a dot (.filename) we must use different syntax to set the block title with the filename.

In the next Ascciidoc markup sample we use different ways to set the block title for a code block with a filename that starts with a dot. First we use the title attribute for the block. Another solution is to use the Unicode value for the dot. Next we enclose the filename in back ticks ( ` ) which also formats the filename with a monotype font. And finally we can define the filename via a document attribute and reference the document attribute in the block title: