Block Processor Extension Example

Purpose: Register a custom block style named shout that uppercases all the words and converts periods to exclamation points.

sample-with-shout-block.adoc

[shout]
The time is now. Get a move on.

ShoutBlock

class ShoutBlock < Asciidoctor::Extensions::BlockProcessor
  PeriodRx = /\.(?= |$)/

  use_dsl

  named :shout
  on_context :paragraph
  name_positional_attributes 'vol'
  parse_content_as :simple

  def process parent, reader, attrs
    volume = ((attrs.delete 'vol') || 1).to_i
    create_paragraph parent, (reader.lines.map {|l| l.upcase.gsub PeriodRx, '!' * volume }), attrs
  end
end

Usage

Asciidoctor::Extensions.register do
  block ShoutBlock
end

Asciidoctor.convert_file 'sample-with-shout-block.adoc', safe: :safe