diff --git a/src/Semantic.hs b/src/Semantic.hs
index cac03c51c..e23c50703 100644
--- a/src/Semantic.hs
+++ b/src/Semantic.hs
@@ -74,6 +74,7 @@ diffBlobPair :: DiffRenderer output -> Both Blob -> Task output
 diffBlobPair renderer blobs = case (renderer, effectiveLanguage) of
   (OldToCDiffRenderer, Just Language.Markdown) -> run (\ blob -> parse markdownParser blob >>= decorate (markupSectionAlgebra blob)) diffTerms (renderToCDiff blobs)
   (OldToCDiffRenderer, Just Language.Python) -> run (\ blob -> parse pythonParser blob >>= decorate (declarationAlgebra blob)) diffTerms (renderToCDiff blobs)
+  (OldToCDiffRenderer, Just Language.Ruby) -> run (\ blob -> parse rubyParser blob >>= decorate (declarationAlgebra blob)) diffTerms (renderToCDiff blobs)
   (OldToCDiffRenderer, _) | Just syntaxParser <- syntaxParser -> run (\ blob -> parse syntaxParser blob >>= decorate (syntaxDeclarationAlgebra blob)) diffSyntaxTerms (renderToCDiff blobs)
 
   (ToCDiffRenderer, Just Language.Markdown) -> run (\ blob -> parse markdownParser blob >>= decorate (markupSectionAlgebra blob)) diffTerms (renderToCDiff blobs)