79. Load and Convert Strings

To parse an AsciiDoc-formatted string into a document object model, use:

doc = Asciidoctor.load '*This* is Asciidoctor.'

To convert the AsciiDoc-formatted string instead, use:

puts Asciidoctor.convert '*This* is Asciidoctor.'

When converting a string, Asciidoctor does not output a standalone document by default. Instead, it generates embeddable output. Let’s learn why that is and how to control it.

79.1. Embeddable output

When you pass a string to Asciidoctor.convert to convert it to a backend format, such as HTML, this method only returns the converted content for those blocks. It does not include the shell around that content (i.e., the header and footer) that is needed to make a standalone document. Instead, it makes an embeddable document. This default was chosen to make Asciidoctor consistent with other lightweight markup processors like Markdown.

Here’s what’s included in an embeddable document:

  • The document title, but only if the showtitle attribute is set (no attribution and revision information)

  • The table of contents if the toc attribute is enabled (and not macro or preamble)

  • The converted document body

  • The footnotes unless the nofootnotes attribute is set

You can still generate a standalone document when converting a string. To go from an AsciiDoc string to a standalone output document, you need to explicitly set the :header_footer option to true.

puts Asciidoctor.convert '*This* is Asciidoctor.', header_footer: true

Now you’ll get back a full HTML 5 file.

You can get the same behavior when converting a file by setting the :header_footer option to false. However, most of the time you’ll want to generate a standalone document when converting a file (which is the default).

Another way to implicitly enable the shell is to output the result to a file. In this case, the default output behavior changes from embeddable to standalone.

puts Asciidoctor.convert '*This* is Asciidoctor.', to_file: 'out.html'

When converting a string, the TOC is only included by default when using the :header_footer option as shown above. However, you can force it to be included without the header and footer by setting the toc attribute with a value of macro and using the toc::[] macro in the string itself.

79.2. Convert inline markup only

If you only want the inline markup to be returned, set the :doctype option to 'inline':

puts Asciidoctor.convert '*This* is Asciidoctor.', :doctype => 'inline'

In this mode, Asciidoctor will only process the first block (e.g., paragraph) in the document and ignore the rest.

79.3. Convert to DocBook

You can produce DocBook 5.0 by setting the backend option to 'docbook'. Since embeddable DocBook isn’t that useful, we also enable the shell (i.e., header and footer) by setting the :header_footer option to true.

puts Asciidoctor.convert '*This* is Asciidoctor.', :header_footer => true,
  :backend => 'docbook'

Let’s say you don’t like some (or all) of the output that Asciidoctor produces. That’s no problem. You can change it. And yes, any of it! Let’s find out how to customize the output Asciidoctor spits out in the next chapter.