PlantUML support for Markdown

Allow rendering of PlantUML diagrams in Markdown documents using fenced blocks:

    ```plantuml
    Bob -> Sara : Hello
    Sara -> Bob : Go away
    ```

Closes: #4048

1 files changed, 21 insertions, 0 deletions

diff --git a/lib/rouge/lexers/plantuml.rb b/lib/rouge/lexers/plantuml.rb
new file mode 100644
index 00000000000..7d5700b7f6d
--- /dev/null
+++ b/lib/rouge/lexers/plantuml.rb
@@ -0,0 +1,21 @@
+module Rouge
+  module Lexers
+    class Plantuml < Lexer
+      title "A passthrough lexer used for PlantUML input"
+      desc "A boring lexer that doesn't highlight anything"
+
+      tag 'plantuml'
+      mimetypes 'text/plain'
+
+      default_options token: 'Text'
+
+      def token
+        @token ||= Token[option :token]
+      end
+
+      def stream_tokens(string, &b)
+        yield self.token, string
+      end
+    end
+  end
+end