resolves #30 automatically generate stylesheet for Pygments (PR #116)

- automatically generate stylesheet for Pygments
- add pygments.rb as a development dependency
- add test to verify integration with Pygments
- document integration with Pygments
- disable feature when using JRuby

README.adoc

@@ -641,6 +641,40 @@ You need to augment the layout to include resources typically present in a stand
 <link rel="stylesheet" href="{{ "/css/asciidoc.css" | prepend: site.baseurl }}">
 ----
 
+=== Stylesheet for Code Highlighting
+
+Asciidoctor integrates with Pygments to provide code highlighting of source blocks in AsciiDoc content.
+This integration is separate from the Pygments integration in Jekyll.
+As part of this integration, Asciidoctor generates a custom stylesheet tailored specially to work with the HTML that Asciidocotor produces.
+Since this stylesheet is backed by the Pygments API, it provides access to all the themes in Pygments
+
+This plugin will automatically generate a stylesheet for Pygments into the source directory if the AsciiDoc attributes in your site's {path-config} are configured as follows:
+
+* `source-highlighter` has the value `pygments`
+* `pygments-css` has the value `class` or is not set
+* `pygments-stylesheet` is not unset (if set, it can have any value)
+
+By default, the stylesheet is written to `stylesdir` + `pygments-stylesheet`.
+If the `pygments-stylesheet` attribute is not specified, the value defaults to `asciidoc-pygments.css`.
+You can customize this value to your liking.
+
+The Pygments theme is selected by the value of the `pygments-style` attribute.
+If this attribute is not set, it defaults to `vs`.
+
+The stylesheet file will be created if it does not yet exist or the theme has been changed.
+Jekyll will handle copying the file to the output directory.
+
+You'll need to add a line to your template to link to this stylesheet, such as:
+
+[source,html]
+----
+<link rel="stylesheet" href="{{ "/css/asciidoc-pygments.css" | prepend: site.baseurl }}">
+----
+
+To disable this feature, either set the `pygments-css` to `style` (to enable inline styles) or unset the `pygments-stylesheet` attribute in your site's {path-config}.
+
+NOTE: It may still be necessary to make some tweaks to your site's stylesheet to accomodate this integration.
+
 === Font-based Admonition and Inline Icons
 
 To enable font-based admonition and inline icons, you first need to add Font Awesome to [path]_{empty}_includes/head.html_ file under the asciidoc.css declaration:

jekyll-asciidoc.gemspec

@@ -24,4 +24,5 @@ Gem::Specification.new do |s|
 
   s.add_development_dependency 'rake'
   s.add_development_dependency 'rspec', '~> 3.0'
+  s.add_development_dependency 'pygments.rb', '~> 0.6.3' unless RUBY_ENGINE == 'jruby'
 end

lib/jekyll-asciidoc/integrator.rb

@@ -42,6 +42,12 @@ def generate site
             (converter.matches doc.extname) ? (integrate doc, name) : true
           end
         end
+
+        if (attrs = site.config['asciidoctor'][:attributes]) &&
+            ((attrs['source-highlighter'] || '').chomp '@') == 'pygments' &&
+            ((attrs['pygments-css'] || '').chomp '@') != 'style' && attrs.fetch('pygments-stylesheet', '')
+          generate_pygments_stylesheet site, attrs
+        end
       end
 
       # Integrate the page-related attributes from the AsciiDoc document header
@@ -86,6 +92,28 @@ def integrate document, collection_name = nil
         document.extend NoLiquid unless document.data['liquid']
         document.data.fetch 'published', true
       end
+
+      def generate_pygments_stylesheet site, attrs
+        css_base = site.source
+        unless (css_dir = (attrs['stylesdir'] || '').chomp '@').empty? || (css_dir.start_with? '/')
+          css_dir = %(/#{css_dir})
+        end
+        if (css_name = attrs['pygments-stylesheet']).nil_or_empty?
+          css_name = 'asciidoc-pygments.css'
+        end
+        css_file = ::File.join css_base, css_dir, css_name
+        css_style = (attrs['pygments-style'] || 'vs').chomp '@'
+        css = ::Asciidoctor::Stylesheets.instance.pygments_stylesheet_data css_style
+        # NOTE apply stronger CSS rule for general text color
+        css = css.sub('.listingblock .pygments  {', '.listingblock .pygments, .listingblock .pygments code {')
+        if site.static_files.any? {|f| f.path == css_file }
+          ::IO.write css_file, css unless css == (::IO.read css_file)
+        else
+          ::Asciidoctor::Helpers.mkdir_p(::File.dirname css_file)
+          ::IO.write css_file, css
+          site.static_files << (::Jekyll::StaticFile.new site, css_base, css_dir, css_name)
+        end
+      end
     end
   end
 end

spec/fixtures/pygments_code_highlighting/_config.yml

@@ -0,0 +1,6 @@
+gems:
+  - jekyll-asciidoc
+asciidoctor:
+  attributes:
+    - stylesdir=/css
+    - source-highlighter=pygments@

spec/fixtures/pygments_code_highlighting/_layouts/page.html

@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>{{ page.title }}</title>
+<link rel="stylesheet" href="{{ "/css/asciidoc-pygments.css" | prepend: site.baseurl }}">
+</head>
+<body>
+<div class="page-content">
+{{ content }}
+</div>
+</body>
+</html>

spec/fixtures/pygments_code_highlighting/page-with-code.adoc

@@ -0,0 +1,16 @@
+= Code
+
+```ruby
+class NilClass
+  alias :nil_or_empty? :nil?
+end
+
+class String
+  def nil_or_empty?
+    alias :nil_or_empty? :empty? 
+  end
+end
+
+v = nil
+puts v.nil_or_empty?
+```

spec/jekyll-asciidoc_spec.rb

@@ -765,6 +765,55 @@
     end if ::Jekyll::MIN_VERSION_3
   end
 
+  describe 'pygments code highlighting' do
+    let :name do
+      'pygments_code_highlighting'
+    end
+
+    before :each do
+      site.process
+    end
+
+    it 'should write the pygments stylesheet to the stylesdir' do
+      src_file = source_file 'css/asciidoc-pygments.css'
+      out_file = output_file 'css/asciidoc-pygments.css'
+      begin
+        expect(::File).to exist(src_file)
+        expect(::File).to exist(out_file)
+        src_content = ::File.read src_file
+        out_content = ::File.read out_file
+        expect(src_content).to eql(out_content)
+      ensure
+        if ::File.exist? src_file
+          ::File.delete src_file
+          ::Dir.rmdir(::File.dirname src_file)
+        end
+      end
+    end
+
+    it 'should overwrite pygments stylesheet if style has changed' do
+      src_file = source_file 'css/asciidoc-pygments.css'
+      out_file = output_file 'css/asciidoc-pygments.css'
+      begin
+        src_content = ::File.read src_file
+        out_content = ::File.read src_file
+        attrs = site.config['asciidoctor'][:attributes]
+        attrs['pygments-style'] = 'monokai'
+        integrator = site.generators.find {|g| ::Jekyll::AsciiDoc::Integrator === g }
+        integrator.generate_pygments_stylesheet site, attrs 
+        expect(::File.read src_file).not_to eql(src_content)
+        ::Jekyll::StaticFile.reset_cache
+        site.process
+        expect(::File.read out_file).not_to eql(out_content)
+      ensure
+        if ::File.exist? src_file
+          ::File.delete src_file
+          ::Dir.rmdir(::File.dirname src_file)
+        end
+      end
+    end
+  end unless RUBY_ENGINE == 'jruby'
+
   describe 'xhtml syntax' do
     let :name do
       'xhtml_syntax'