Merge pull request #333 from Mogztter/yield-duplication

Use content_for and yield_content to remove code duplication
asciidoctor · Feb 11, 2020 · b0b9f4f · b0b9f4f
2 parents ad91f8e + 81d4bb7
commit b0b9f4f
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Showing 2 changed files with 92 additions and 44 deletions.
diff --git a/templates/helpers.rb b/templates/helpers.rb
@@ -144,8 +144,69 @@ def revealjs_dependencies(document, node, revealjsdir)
   def resolve_content
     @content_model == :simple ? %(<p>#{content}</p>) : content
   end
-  #--
 
+  # Capture nested template content and register it with the specified key, to
+  # be executed at a later time.
+  #
+  # This method must be invoked using the control code directive (i.e., -). By
+  # using a control code directive, the block is set up to append the result
+  # directly to the output buffer. (Integrations often hide the distinction
+  # between a control code directive and an output directive in this context).
+  #
+  # key   - The Symbol under which to save the template block.
+  # opts  - A Hash of options to control processing (default: {}):
+  #         * :append  - A Boolean that indicates whether to append this block
+  #                      to others registered with this key (default: false).
+  #         * :content - String content to be used if template content is not
+  #                      provided (optional).
+  # block - The template content (in Slim template syntax).
+  #
+  # Examples
+  #
+  #   - content_for :body
+  #     p content
+  #   - content_for :body, append: true
+  #     p more content
+  #
+  # Returns nothing.
+  def content_for key, opts = {}, &block
+    @content = {} unless defined? @content
+    (opts[:append] ? (@content[key] ||= []) : (@content[key] = [])) << (block_given? ? block : lambda { opts[:content] })
+    nil
+  end
+
+  # Checks whether deferred template content has been registered for the specified key.
+  #
+  # key - The Symbol under which to look for saved template blocks.
+  #
+  # Returns a Boolean indicating whether content has been registered for this key.
+  def content_for? key
+    (defined? @content) && (@content.key? key)
+  end
+
+  # Evaluates the deferred template content registered with the specified key.
+  #
+  # When the corresponding content_for method is invoked using a control code
+  # directive, the block is set up to append the result to the output buffer
+  # directly.
+  #
+  # key  - The Symbol under which to look for template blocks to yield.
+  # opts - A Hash of options to control processing (default: {}):
+  #        * :drain - A Boolean indicating whether to drain the key of blocks
+  #                   after calling them (default: true).
+  #
+  # Examples
+  #
+  #   - yield_content :body
+  #
+  # Returns nothing (assuming the content has been captured in the context of control code).
+  def yield_content key, opts = {}
+    if (defined? @content) && (blks = (opts.fetch :drain, true) ? (@content.delete key) : @content[key])
+      blks.map {|b| b.call }.join
+    end
+    nil
+  end
+  #--
 end
 
 # More custom functions can be added in another namespace if required

diff --git a/templates/section.html.slim b/templates/section.html.slim
@@ -33,32 +33,38 @@
 - if attr? 'background-color'
   - data_background_color = attr 'background-color'
 
-/ RENDERING
-/ render parent section of vertical slides set
-- if @level == 1 && !vertical_slides.empty?
-  section
-    / TODO: try to get rid of duplication w/ standalone slide section
-    section(id=(titleless ? nil : id)
-      class=roles
-      data-transition=(attr 'transition')
-      data-transition-speed=(attr 'transition-speed')
-      data-background-color=data_background_color
-      data-background-image=data_background_image
-      data-background-size=(data_background_size || attr('background-size'))
-      data-background-repeat=(data_background_repeat || attr('background-repeat'))
-      data-background-transition=(data_background_transition || attr('background-transition'))
-      data-background-position=(data_background_position || attr('background-position'))
-      data-background-iframe=(attr "background-iframe")
-      data-background-video=(attr "background-video")
-      data-background-video-loop=((attr? 'background-video-loop') || (option? 'loop'))
-      data-background-video-muted=((attr? 'background-video-muted') || (option? 'muted'))
-      data-background-opacity=(attr "background-opacity")
-      data-state=(attr 'state'))
+- parent_section_with_vertical_slides = @level == 1 && !vertical_slides.empty?
 
-      - unless hide_title
-        h2=section_title
+- content_for :section
+  section(id=(titleless ? nil : id)
+    class=roles
+    data-transition=(attr 'transition')
+    data-transition-speed=(attr 'transition-speed')
+    data-background-color=data_background_color
+    data-background-image=data_background_image
+    data-background-size=(data_background_size || attr('background-size'))
+    data-background-repeat=(data_background_repeat || attr('background-repeat'))
+    data-background-transition=(data_background_transition || attr('background-transition'))
+    data-background-position=(data_background_position || attr('background-position'))
+    data-background-iframe=(attr "background-iframe")
+    data-background-video=(attr "background-video")
+    data-background-video-loop=((attr? 'background-video-loop') || (option? 'loop'))
+    data-background-video-muted=((attr? 'background-video-muted') || (option? 'muted'))
+    data-background-opacity=(attr "background-opacity")
+    data-state=(attr 'state'))
+    - unless hide_title
+      h2=section_title
+    - if parent_section_with_vertical_slides
       - (blocks - vertical_slides).each do |block|
         =block.convert
+    - else
+      =content.chomp
+
+/ RENDERING
+/ render parent section of vertical slides set
+- if parent_section_with_vertical_slides
+  section
+    - yield_content :section
     - vertical_slides.each do |subsection|
       =subsection.convert
 
@@ -69,23 +75,4 @@
     h level=(@level) =title
     =content.chomp
   - else
-    section(id=(titleless ? nil : id)
-      class=roles
-      data-transition=(attr 'transition')
-      data-transition-speed=(attr 'transition-speed')
-      data-background-color=data_background_color
-      data-background-image=data_background_image
-      data-background-size=(data_background_size || attr('background-size'))
-      data-background-repeat=(data_background_repeat || attr('background-repeat'))
-      data-background-transition=(data_background_transition || attr('background-transition'))
-      data-background-position=(data_background_position || attr('background-position'))
-      data-background-iframe=(attr "background-iframe")
-      data-background-video=(attr "background-video")
-      data-background-video-loop=((attr? 'background-video-loop') || (option? 'loop'))
-      data-background-video-muted=((attr? 'background-video-muted') || (option? 'muted'))
-      data-background-opacity=(attr "background-opacity")
-      data-state=(attr 'state'))
-
-      - unless hide_title
-        h2=section_title
-      =content.chomp
+    - yield_content :section