Module: Nanoc3::Helpers::Capturing

Included in:
Filtering, Rendering
Defined in:
lib/nanoc3/helpers/capturing.rb

Overview

Provides functionality for “capturing” content in one place and reusing this content elsewhere.

For example, suppose you want the sidebar of your site to contain a short summary of the item. You could put the summary in the meta file, but that’s not possible when the summary contains eRuby. You could also put the sidebar inside the actual item, but that’s not very pretty. Instead, you write the summary on the item itself, but capture it, and print it in the sidebar layout.

Examples:

Capturing content into a content_for_summary attribute

<% content_for :summary do %>
  <p>On this item, nanoc is introduced, blah blah.</p>
<% end %>

Showing captured content in a sidebar

<div id="sidebar">
  <h3>Summary</h3>
  <%= @item[:content_for_summary] || '(no summary)' %>
</div>

Instance Method Summary (collapse)

Instance Method Details

- (String) capture(&block)

Evaluates the given block and returns the result. The contents of the block is not outputted.

This function has been tested with ERB and Haml. Other filters may not work correctly.

Returns:

  • (String) —

    The captured result



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# File 'lib/nanoc3/helpers/capturing.rb', line 48

def capture(&block)
  # Get erbout so far
  erbout = eval('_erbout', block.binding)
  erbout_length = erbout.length

  # Execute block
  block.call

  # Get new piece of erbout
  erbout_addition = erbout[erbout_length..-1]

  # Remove addition
  erbout[erbout_length..-1] = ''

  # Done
  erbout_addition
end

- (void) content_for(name, &block)

This method returns an undefined value.

Captures the content inside the block and stores it in an item attribute named content_for_ followed by the given name. The content of the block itself will not be outputted.

content should be stored

Parameters:

  • The (Symbol, String) —

    base name of the attribute into which the



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# File 'lib/nanoc3/helpers/capturing.rb', line 37

def content_for(name, &block)
  eval("@item[:content_for_#{name.to_s}] = capture(&block)")
end