Add highlighting through rouge.

lib/org-ruby/highlighter.rb

@@ -0,0 +1,61 @@
+module Orgmode
+  # Highlight code
+  module Highlighter
+    def self.highlight(code, lang)
+      highlighter = guess_highlighter
+      highlighter.highlight(code, lang)
+    end
+
+    def self.guess_highlighter
+      return RougeHighliter if gem_present?('rouge')
+      return PygmentsHighliter if gem_present?('pygments.rb')
+      return CodeRayHighliter if gem_present?('coderay')
+
+      DefaultHighliter
+    end
+
+    def self.gem_present?(gem)
+      Gem::Specification.find_all_by_name(gem).any?
+    end
+
+    # Default highliter does nothing to code
+    class DefaultHighliter
+      def self.highlight(buffer, _lang)
+        buffer
+      end
+    end
+
+    # Pygments wrapper
+    class PygmentsHighliter
+      def self.highlight(buffer, lang)
+        require 'pygments'
+        if Pygments::Lexer.find_by_alias(lang)
+          Pygments.highlight(buffer, lexer: lang)
+        else
+          Pygments.highlight(buffer, lexer: 'text')
+        end
+      end
+    end
+
+    # CodeRay wrapper
+    class CodeRayHighliter
+      def self.highlight(buffer, lang)
+        require 'coderay'
+        CodeRay.scan(buffer, lang).html(wrap: nil, css: :style)
+      rescue ArgumentError => _e
+        CodeRay.scan(buffer, 'text').html(wrap: nil, css: :style)
+      end
+    end
+
+    # Rouge wrapper
+    class RougeHighliter
+      def self.highlight(buffer, lang)
+        require 'rouge'
+        formatter = Rouge::Formatters::HTMLLegacy.new
+        lexer = Rouge::Lexer.find_fancy(lang, buffer) ||
+                Rouge::Lexers::PlainText
+        formatter.format(lexer.lex(buffer.strip))
+      end
+    end
+  end
+end

lib/org-ruby/html_output_buffer.rb

@@ -1,7 +1,7 @@
 module Orgmode
 
   class HtmlOutputBuffer < OutputBuffer
-
+    require_relative './highlighter.rb'
     HtmlBlockTag = {
       :paragraph        => "p",
       :ordered_list     => "ol",
@@ -37,20 +37,6 @@ def initialize(output, opts = {})
       @unclosed_tags = []
       @logger.debug "HTML export options: #{@options.inspect}"
       @custom_blocktags = {} if @options[:markup_file]
-
-      unless @options[:skip_syntax_highlight]
-        begin
-          require 'pygments'
-        rescue LoadError
-          # Pygments is not supported so we try instead with CodeRay
-          begin
-            require 'coderay'
-          rescue LoadError
-            # No code syntax highlighting
-          end
-        end
-      end
-
       if @options[:markup_file]
         do_custom_markup
       end
@@ -64,7 +50,7 @@ def push_mode(mode, indent, properties={})
       super(mode, indent, properties)
       if HtmlBlockTag[mode]
         unless ((mode_is_table?(mode) and skip_tables?) or
-                (mode == :src and !@options[:skip_syntax_highlight] and defined? Pygments))
+                (mode == :src and !@options[:skip_syntax_highlight]))
           css_class = case
                       when (mode == :src and @block_lang.empty?)
                         " class=\"src\""
@@ -100,7 +86,7 @@ def pop_mode(mode = nil)
       m = super(mode)
       if HtmlBlockTag[m]
         unless ((mode_is_table?(m) and skip_tables?) or
-                (m == :src and !@options[:skip_syntax_highlight] and defined? Pygments))
+                (m == :src and !@options[:skip_syntax_highlight]))
           add_paragraph if @new_paragraph
           @new_paragraph = true
           @logger.debug "</#{HtmlBlockTag[m]}>"
@@ -110,6 +96,10 @@ def pop_mode(mode = nil)
       @list_indent_stack.pop
     end
 
+    def highlight(code, lang)
+      Highlighter.highlight code, lang
+    end
+
     def flush!
       return false if @buffer.empty?
       case
@@ -121,29 +111,9 @@ def flush!
         case
         when (current_mode == :src and @options[:skip_syntax_highlight])
           @buffer = escapeHTML @buffer
-        when (current_mode == :src and defined? Pygments)
+        when (current_mode == :src)
           lang = normalize_lang @block_lang
-          @output << "\n" unless @new_paragraph == :start
-          @new_paragraph = true
-
-          begin
-            @buffer = Pygments.highlight(@buffer, :lexer => lang)
-          rescue
-            # Not supported lexer from Pygments, we fallback on using the text lexer
-            @buffer = Pygments.highlight(@buffer, :lexer => 'text')
-          end
-        when (current_mode == :src and defined? CodeRay)
-          lang = normalize_lang @block_lang
-
-          # CodeRay might throw a warning when unsupported lang is set,
-          # then fallback to using the text lexer
-          silence_warnings do
-            begin
-              @buffer = CodeRay.scan(@buffer, lang).html(:wrap => nil, :css => :style)
-            rescue ArgumentError
-              @buffer = CodeRay.scan(@buffer, 'text').html(:wrap => nil, :css => :style)
-            end
-          end
+          @buffer = highlight @buffer, lang
         when (current_mode == :html or current_mode == :raw_text)
           @buffer.gsub!(/\A\n/, "") if @new_paragraph == :start
           @new_paragraph = true