diff --git a/default.nix b/default.nix
index 59a59136..a4b135e2 100644
--- a/default.nix
+++ b/default.nix
@@ -77,7 +77,6 @@ let
 
       in
         {
-          xo-flatstring     = self.callPackage pkgs/xo-flatstring.nix     { buildDocs = true; };
           xo-ratio          = self.callPackage pkgs/xo-ratio.nix          { buildDocs = true; };
           xo-unit           = self.callPackage pkgs/xo-unit.nix           { buildDocs = true; };
 #
@@ -104,6 +103,7 @@ let
             xo-subsys         = self.callPackage pkgs/xo-subsys.nix         {};
             xo-randomgen      = self.callPackage pkgs/xo-randomgen.nix      {                   buildExamples = true; };
             xo-ordinaltree    = self.callPackage pkgs/xo-ordinaltree.nix    {};
+            xo-flatstring     = self.callPackage pkgs/xo-flatstring.nix     { buildDocs = true; buildExamples = true; };
             xo-pyutil         = self.callPackage pkgs/xo-pyutil.nix         {};
             xo-reflectutil    = self.callPackage pkgs/xo-reflectutil.nix    {};
             xo-reflect        = self.callPackage pkgs/xo-reflect.nix        {};
diff --git a/pkgs/xo-flatstring.nix b/pkgs/xo-flatstring.nix
index 2c141450..d73ecf0b 100644
--- a/pkgs/xo-flatstring.nix
+++ b/pkgs/xo-flatstring.nix
@@ -9,6 +9,7 @@
   xo-cmake, xo-indentlog,
 
   buildDocs ? false,
+  buildExamples ? false,
 } :
 
 stdenv.mkDerivation (finalattrs:
@@ -29,9 +30,13 @@ stdenv.mkDerivation (finalattrs:
     # guessing may need this for doxygen etc
     # env.LC_ALL = "en_US.UTF-8";
 
-    cmakeFlags = ["-DCMAKE_MODULE_PATH=${xo-cmake}/share/cmake"];
+    cmakeFlags = ["-DCMAKE_MODULE_PATH=${xo-cmake}/share/cmake"]
+                 ++ lib.optionals buildDocs ["-DXO_ENABLE_DOCS=on"]
+                 ++ lib.optionals buildExamples ["-DXO_ENABLE_EXAMPLES=on"];
 
     inherit buildDocs;
+    inherit buildExamples;
+
     doCheck = true;
 
     postBuild = lib.optionalString buildDocs ''
@@ -54,7 +59,8 @@ stdenv.mkDerivation (finalattrs:
       graphviz
       python3Packages.sphinx-rtd-theme
       python3Packages.breathe
-    ]
-    ;
+      python3Packages.sphinxcontrib-ditaa
+      python3Packages.sphinxcontrib-plantuml
+    ];
 
   })