diff --git a/include/xo/indentlog/print/ppdetail_atomic.hpp b/include/xo/indentlog/print/ppdetail_atomic.hpp
index 3f2a3c3f..cc50770a 100644
--- a/include/xo/indentlog/print/ppdetail_atomic.hpp
+++ b/include/xo/indentlog/print/ppdetail_atomic.hpp
@@ -1,17 +1,17 @@
-/* ppdetail_atomic.hpp
+/** @file ppdetail_atomic.hpp
  *
- * author: Roland Conybeare, Jul 2025
- */
+ *  @author Roland Conybeare, Jul 2025
+ **/
 
 #pragma once
 
+#include "ppindentinfo.hpp"
 #include <string>
 #include <cstdint>
 
 namespace xo {
     namespace print {
         struct ppstate; // see pretty.hpp
-        struct ppindentinfo;
 
         // Defining this means ppdetail_atomic -> ppdetail.
         // For debugging suppress the #define; causes specialization of ppdetail_atomic to be required for every T
@@ -22,28 +22,6 @@ namespace xo {
         //
 #define ppdetail_atomic ppdetail
 
-        struct ppindentinfo {
-            ppindentinfo(ppstate * pps, std::uint32_t ci0, std::uint32_t indent_width, bool upto)
-                : pps_{pps}, ci0_{ci0}, ci1_{ci0 + indent_width}, upto_{upto} {}
-
-            ppstate * pps() const { return pps_; }
-            std::uint32_t ci0_unused() const { return ci0_; }
-            std::uint32_t ci1() const { return ci1_; }
-            bool upto() const { return upto_; }
-
-        private:
-            ppstate * pps_ = nullptr;
-            /** current indent **/
-            std::uint32_t ci0_ = 0;
-            /** ci0 +1 indent level **/
-            std::uint32_t ci1_ = 0;
-            /**
-             *  true  -> print on remainder of current line, unless past right margin
-             *  false -> pretty across across multiple lines
-             **/
-            bool upto_;
-        };
-
         /** @class ppdetail
          *  @brief template for opt-in to pretty-printer
          *
diff --git a/include/xo/indentlog/print/ppindentinfo.hpp b/include/xo/indentlog/print/ppindentinfo.hpp
new file mode 100644
index 00000000..6137e6f9
--- /dev/null
+++ b/include/xo/indentlog/print/ppindentinfo.hpp
@@ -0,0 +1,43 @@
+/** @file ppindentinfo.hpp
+ *
+ *  @author Roland Conybeare, Jul 2025
+ **/
+
+#pragma once
+
+#include <cstdint>
+
+namespace xo {
+    namespace print {
+        struct ppstate;
+
+        /** @class ppindentinfo
+         *  @brief pretty-printing state passed down the stack while traversing object graph
+         **/
+        struct ppindentinfo {
+            ppindentinfo(ppstate * pps, std::uint32_t ci0, std::uint32_t indent_width, bool upto)
+                : pps_{pps}, ci0_{ci0}, ci1_{ci0 + indent_width}, upto_{upto} {}
+
+            ppstate * pps() const { return pps_; }
+            std::uint32_t ci0_unused() const { return ci0_; }
+            std::uint32_t ci1() const { return ci1_; }
+            bool upto() const { return upto_; }
+
+        private:
+            /** pretty-printing state. flyweight. See [xo/indentlog/print/pretty.hpp] **/
+            ppstate * pps_ = nullptr;
+            /** current indent **/
+            std::uint32_t ci0_ = 0;
+            /** ci0 +1 indent level **/
+            std::uint32_t ci1_ = 0;
+            /**
+             *  true  -> print on remainder of current line, unless past right margin
+             *  false -> pretty across across multiple lines
+             **/
+            bool upto_;
+        };
+
+    }
+}
+
+/* end ppindentinfo.hpp */