Merge pull request #9 from Alwinator/feature/8_hide-if-empty-list-sample

Fix #8

.github/workflows/test.yml

@@ -23,6 +23,9 @@ jobs:
       - name: Build enhanced-rendering as PDF
         run: asciidoctor-pdf -a allow-uri-read -r asciidoctor-lists samples/enhanced-rendering.adoc
 
+      - name: Build hide-if-empty-list-sample as PDF
+        run: asciidoctor-pdf -a allow-uri-read -r asciidoctor-lists samples/hide-if-empty-list-sample.adoc
+
       - name: Archive production artifacts
         uses: actions/upload-artifact@v2
         with:

README.adoc

@@ -50,6 +50,11 @@ Allows rendering links in the caption
 
 Sample: link:samples/enhanced-rendering.adoc[]
 
+=== hide_empty_section
+Removes the section when no elements are found
+
+Sample: link:samples/hide-if-empty-list-sample.adoc
+
 == Docker
 [source,bash]
 ----

lib/asciidoctor-lists/extensions.rb

@@ -12,12 +12,14 @@ class ListMacro < ::Asciidoctor::Extensions::BlockMacroProcessor
     use_dsl
     named :"list-of"
     name_positional_attributes 'enhanced_rendering'
+    name_positional_attributes 'hide_empty_section'
 
     def process(parent, target, attrs)
       uuid = SecureRandom.uuid
       ListMacroAttributes[uuid] = {
         element: target,
-        enhanced_rendering: attrs['enhanced_rendering']
+        enhanced_rendering: attrs['enhanced_rendering'],
+        hide_empty_section: attrs['hide_empty_section']
       }
       create_paragraph parent, uuid, {}
     end
@@ -36,28 +38,34 @@ def process(document)
 
          params = ListMacroAttributes[block.lines[0]]
          enhanced_rendering = params[:enhanced_rendering]
+         hide_empty_section = params[:hide_empty_section]
 
-         document.find_by(context: params[:element].to_sym).each do |element|
+         elements = document.find_by(context: params[:element].to_sym)
+         if elements.length > 0
+           elements.each do |element|
 
-           if element.caption or element.title
-             unless element.id
-               element.id = SecureRandom.uuid
-             end
+             if element.caption or element.title
+               unless element.id
+                 element.id = SecureRandom.uuid
+               end
 
-             if enhanced_rendering
-                 if element.caption
-                   references_asciidoc << %(xref:#{element.id}[#{element.caption}]#{element.instance_variable_get(:@title)} +)
-                 else element.caption
-                   references_asciidoc << %(xref:#{element.id}[#{element.instance_variable_get(:@title)}] +)
+               if enhanced_rendering
+                   if element.caption
+                     references_asciidoc << %(xref:#{element.id}[#{element.caption}]#{element.instance_variable_get(:@title)} +)
+                   else element.caption
+                     references_asciidoc << %(xref:#{element.id}[#{element.instance_variable_get(:@title)}] +)
+                   end
+                 else
+                   if element.caption
+                    references_asciidoc << %(xref:#{element.id}[#{element.caption}]#{element.title} +)
+                   else element.caption
+                    references_asciidoc << %(xref:#{element.id}[#{element.title}] +)
                  end
-               else
-                 if element.caption
-                  references_asciidoc << %(xref:#{element.id}[#{element.caption}]#{element.title} +)
-                 else element.caption
-                  references_asciidoc << %(xref:#{element.id}[#{element.title}] +)
                end
              end
            end
+         elsif hide_empty_section
+           block.parent.parent.blocks.delete block.parent
          end
 
          block_index = block.parent.blocks.index do |b|

samples/hide-if-empty-list-sample.adoc

@@ -0,0 +1,14 @@
+== Test the List Macro for empty lists
+:listing-caption: Code
+
+.Another wikipedia SVG image
+image::https://upload.wikimedia.org/wikipedia/commons/thumb/4/4f/SVG_Logo.svg/400px-SVG_Logo.svg.png[SVG,100,100]
+
+=== List of figures
+list-of::image[hide_empty_section=true]
+
+=== List of tables
+list-of::table[hide_empty_section=true]
+
+=== List of code snippets
+list-of::listing[]