gnu: Add r-dendextend.

* gnu/packages/cran.scm (r-dendextend): New variable.

gnu/packages/cran.scm

@@ -309,3 +309,32 @@ (define-public r-compare
 instructed to explore various modifications of the objects (e.g., sorting
 rows, dropping names) to see if the modified versions are identical.")
     (license license:gpl2+)))
+
+(define-public r-dendextend
+  (package
+    (name "r-dendextend")
+    (version "1.5.2")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (cran-uri "dendextend" version))
+       (sha256
+        (base32
+         "04jz58apibfrkjcrdmw2hmsav6qpb5cs6qdai81k1v1iznfcya42"))))
+    (build-system r-build-system)
+    (propagated-inputs
+     `(("r-fpc" ,r-fpc)
+       ("r-ggplot2" ,r-ggplot2)
+       ("r-magrittr" ,r-magrittr)
+       ("r-viridis" ,r-viridis)
+       ("r-whisker" ,r-whisker)))
+    (home-page "https://cran.r-project.org/web/packages/dendextend")
+    (synopsis "Extending 'dendrogram' functionality in R")
+    (description
+     "This package offers a set of functions for extending @code{dendrogram}
+objects in R, letting you visualize and compare trees of hierarchical
+clusterings.  You can adjust a tree's graphical parameters (the color, size,
+type, etc of its branches, nodes and labels) and visually and statistically
+compare different dendrograms to one another.")
+    ;; Any of these versions
+    (license (list license:gpl2 license:gpl3))))