old_contents: var _ = require('lodash');
  
  module.exports = {
      // Return non-parsed html
      // since blocks are by default non-parsable, a simple identity method works fine
      html: _.identity,
  
      // Highlight a code block
      // This block can be replaced by plugins
      code: function(blk) {
          return {
              html: false,
              body: blk.body
          };
      }
  };
  
new_contents: var _ = require('lodash');
  
  module.exports = {
      // Return non-parsed html
      // since blocks are by default non-parsable, a simple identity method works fine
      html: _.identity,
  
      // Highlight a code block
      // This block can be replaced by plugins
      code: function(blk) {
          return {
              html: false,
              body: blk.body
          };
      },
  
      // Render some markdown to HTML
      markdown: function(blk) {
          return this.book.renderInline('markdown', blk.body)
          .then(function(out) {
              return { body: out };
          });
      },
      asciidoc: function(blk) {
          return this.book.renderInline('asciidoc', blk.body)
          .then(function(out) {
              return { body: out };
          });
      },
      markup: function(blk) {
          return this.book.renderInline(this.ctx.file.type, blk.body)
          .then(function(out) {
              return { body: out };
          });
      }
  };
  
subject: Add block "markdown", "asciidoc" and "markup"