diff --git a/xo-reader/CMakeLists.txt b/xo-reader/CMakeLists.txt
index 0fb90c0c..8c88ff68 100644
--- a/xo-reader/CMakeLists.txt
+++ b/xo-reader/CMakeLists.txt
@@ -12,7 +12,7 @@ xo_cxx_toplevel_options3()
 # ----------------------------------------------------------------
 # c++ settings
 
-set(PROJECT_CXX_FLAGS "")
+set(PROJECT_CXX_FLAGS "-ftemplate-backtrace-limit=0")
 #set(PROJECT_CXX_FLAGS "-fconcepts-diagnostics-depth=2")
 add_definitions(${PROJECT_CXX_FLAGS})
 
@@ -28,3 +28,5 @@ xo_export_cmake_config(${PROJECT_NAME} ${PROJECT_VERSION} ${PROJECT_NAME}Targets
 # must come after them
 #
 add_subdirectory(docs)
+
+# end CMakeLists.txt
diff --git a/xo-reader/docs/README b/xo-reader/docs/README
index ea8a9a25..6aff5d41 100644
--- a/xo-reader/docs/README
+++ b/xo-reader/docs/README
@@ -10,22 +10,22 @@ standalone build
            +------------------------------------------------->| .build/docs/Doxyfile |
            |                                                  +----------------------+
            |                                                     ^
-           |                                 (cmake              |
+           |                                 (cmake)             |
            |                                        /------------/
            |                                        |
-           |     +---------------------------------------+    +-----------------+
-           +---->| doxygen                               |--->| .build/docs/dox |
-           |     |   $PREFIX/share/xo-macros/Doxyfile.in |    |   +- html/      |
-           |     +---------------------------------------+    |   +- xml/       |
-           |                                                  +-----------------+
-           |                                                     |
-           |                                        /------------/
-           |                                        |
-           |                                        v
-           |     +---------------------------------------+    +--------------------+
-           \---->| sphinx                                |--->| .build/docs/sphinx |
-                 |   +- conf.py                          |    |   +- html/         |
-                 |   +- _static/                         |    +--------------------+
+           |     +---------------------------------------+          +-----------------+
+           +---->| doxygen                               |--------->| .build/docs/dox |
+           |     |   $PREFIX/share/xo-macros/Doxyfile.in | (doxygen)|   +- html/      |
+           |     +---------------------------------------+          |   +- xml/       |
+           |                                                        +-----------------+
+           |                                                             |
+           |                                                             |(sphinx)
+           |                                                             |
+           |                                                             v
+           |     +---------------------------------------+        +--------------------+
+           \---->| sphinx                                |------->| .build/docs/sphinx |
+                 |   +- conf.py                          |        |   +- html/         |
+                 |   +- _static/                         |        +--------------------+
                  |   +- *.rst                            |
                  +---------------------------------------+
 
diff --git a/xo-reader/docs/install.rst b/xo-reader/docs/install.rst
index b751ab10..0860150f 100644
--- a/xo-reader/docs/install.rst
+++ b/xo-reader/docs/install.rst
@@ -49,8 +49,8 @@ Minimal Dependencies
 .. _xo-subsys source: https://github.com/rconybea/subsys
 .. _xo-cmake source: https://github.com/rconybea/xo-cmake
 
-Installing from source
-----------------------
+Building from source
+--------------------
 
 Install scripts for XO libraries depend on helper scripts installed from `xo-cmake`.
 
@@ -135,12 +135,11 @@ CMake Support
 
 To use built-in cmake support, when using ``xo-reader`` from another project:
 
-Make sure ``PREFIX/lib/cmake`` is searched by cmake (if necessary, include it in ``CMAKE_PREFIX_PATH``)
+Make sure ``PREFIX/lib/cmake`` is searched by cmake (for example include it in ``CMAKE_PREFIX_PATH``)
 
 Add to your ``CMakeLists.txt``:
 
 .. code-block:: cmake
 
     FindPackage(xo_reader CONFIG REQUIRED)
-
     target_link_libraries(mytarget INTERFACE xo_reader)
diff --git a/xo-reader/examples/exprreplxx/exprreplxx.cpp b/xo-reader/examples/exprreplxx/exprreplxx.cpp
index b9770594..4b3660e4 100644
--- a/xo-reader/examples/exprreplxx/exprreplxx.cpp
+++ b/xo-reader/examples/exprreplxx/exprreplxx.cpp
@@ -61,6 +61,10 @@ int
 main() {
     using namespace replxx;
     using namespace xo::scm;
+    using xo::ast::Expression;
+    using xo::print::ppconfig;
+    using xo::print::ppstate_standalone;
+    using xo::rp;
     using namespace std;
 
     using span_type = xo::scm::span<const char>;
@@ -92,7 +96,10 @@ main() {
             auto [expr, consumed, psz] = rdr.read_expr(input, eof);
 
             if (expr) {
-                cout << expr << endl;
+                ppconfig ppc;
+                ppstate_standalone pps(&cout, 0, &ppc);
+
+                pps.prettyn(expr);
             }
 
             input = input.after_prefix(consumed);
@@ -103,7 +110,10 @@ main() {
     auto [expr, _1, _2] = rdr.read_expr(input, true /*eof*/);
 
     if (expr) {
-        cout << expr << endl;
+        ppconfig ppc;
+        ppstate_standalone pps(&cout, 0, &ppc);
+
+        pps.prettyn<rp<Expression>>(rp<Expression>(expr));
     }
 
     rx.history_save("repl_history.txt");
diff --git a/xo-reader/include/xo/reader/define_xs.hpp b/xo-reader/include/xo/reader/define_xs.hpp
index 0c6d46c8..a2c2616a 100644
--- a/xo-reader/include/xo/reader/define_xs.hpp
+++ b/xo-reader/include/xo/reader/define_xs.hpp
@@ -8,6 +8,7 @@
 #include "xo/expression/DefineExpr.hpp"
 #include "xo/expression/ConvertExpr.hpp"
 #include "exprstate.hpp"
+#include "xo/indentlog/print/ppdetail_atomic.hpp"
 //#include <cstdint>
 
 namespace xo {
@@ -117,6 +118,12 @@ namespace xo {
             rp<ConvertExprAccess> cvt_expr_;
         };
     } /*namespace scm*/
+
+#ifndef ppdetail_atomic
+    namespace print {
+        PPDETAIL_ATOMIC(xo::scm::defexprstatetype);
+    }
+#endif
 } /*namespace xo*/
 
 
diff --git a/xo-reader/include/xo/reader/exprstate.hpp b/xo-reader/include/xo/reader/exprstate.hpp
index f6d592db..83b459c8 100644
--- a/xo-reader/include/xo/reader/exprstate.hpp
+++ b/xo-reader/include/xo/reader/exprstate.hpp
@@ -214,6 +214,13 @@ namespace xo {
             return os;
         };
     } /*namespace scm*/
+
+#ifndef ppdetail_atomic
+    namespace print {
+        PPDETAIL_ATOMIC(xo::scm::exprstatetype);
+        PPDETAIL_ATOMIC(xo::scm::exprstate);
+    } /*namespace print*/
+#endif
 } /*namespace xo*/
 
 /** end exprstate.hpp **/
diff --git a/xo-reader/include/xo/reader/exprstatestack.hpp b/xo-reader/include/xo/reader/exprstatestack.hpp
index b4e57449..ce7bdc1d 100644
--- a/xo-reader/include/xo/reader/exprstatestack.hpp
+++ b/xo-reader/include/xo/reader/exprstatestack.hpp
@@ -7,6 +7,7 @@
 
 #include "exprstate.hpp"
 #include "xo/indentlog/print/vector.hpp"
+#include "xo/indentlog/print/pretty.hpp"
 
 namespace xo {
     namespace scm {
@@ -64,6 +65,21 @@ namespace xo {
             return os;
         }
     } /*namespace scm*/
+
+#ifndef ppdetail_atomic
+    namespace print {
+        template <>
+        struct ppdetail<xo::scm::exprstatestack *> {
+            static bool print_upto(ppstate * pps, const xo::scm::exprstatestack * x) {
+                return ppdetail_atomic<const xo::scm::exprstatestack *>::print_upto(pps, x);
+            }
+            static void print_pretty(ppstate * pps, const xo::scm::exprstatestack * x) {
+                ppdetail_atomic<const xo::scm::exprstatestack *>::print_pretty(pps, x);
+            }
+        };
+    }
+#endif
+
 } /*namespace xo*/
 
 
diff --git a/xo-reader/include/xo/reader/parserstatemachine.hpp b/xo-reader/include/xo/reader/parserstatemachine.hpp
index 7b6d485b..decc1e6c 100644
--- a/xo-reader/include/xo/reader/parserstatemachine.hpp
+++ b/xo-reader/include/xo/reader/parserstatemachine.hpp
@@ -87,6 +87,12 @@ namespace xo {
             return os;
         }
     } /*namespace scm*/
+
+#ifndef ppdetail_atomic
+    namespace print {
+        PPDETAIL_ATOMIC(xo::scm::parserstatemachine);
+    }
+#endif
 } /*namespace xo*/
 
 
diff --git a/xo-reader/include/xo/reader/progress_xs.hpp b/xo-reader/include/xo/reader/progress_xs.hpp
index b162d3ef..47d4c89a 100644
--- a/xo-reader/include/xo/reader/progress_xs.hpp
+++ b/xo-reader/include/xo/reader/progress_xs.hpp
@@ -132,6 +132,12 @@ namespace xo {
             rp<Expression> rhs_;
         };
     } /*namespace scm*/
+
+#ifndef ppdetail_atomic
+    namespace print {
+        PPDETAIL_ATOMIC(xo::scm::optype);
+    }
+#endif
 } /*namespace xo*/
 
 
diff --git a/xo-reader/include/xo/reader/reader.hpp b/xo-reader/include/xo/reader/reader.hpp
index b155f4db..841c3a4d 100644
--- a/xo-reader/include/xo/reader/reader.hpp
+++ b/xo-reader/include/xo/reader/reader.hpp
@@ -7,6 +7,7 @@
 
 #include "parser.hpp"
 #include "xo/expression/Expression.hpp"
+#include "xo/expression/pretty_expression.hpp"
 #include "xo/tokenizer/tokenizer.hpp"
 
 namespace xo {
diff --git a/xo-reader/src/reader/define_xs.cpp b/xo-reader/src/reader/define_xs.cpp
index 85614a5b..6a8f4c7c 100644
--- a/xo-reader/src/reader/define_xs.cpp
+++ b/xo-reader/src/reader/define_xs.cpp
@@ -6,6 +6,7 @@
 #include "expect_symbol_xs.hpp"
 #include "expect_expr_xs.hpp"
 #include "expect_type_xs.hpp"
+#include "pretty_expression.hpp"
 
 namespace xo {
     namespace scm {
diff --git a/xo-reader/src/reader/expect_expr_xs.cpp b/xo-reader/src/reader/expect_expr_xs.cpp
index ed7aea54..b318966e 100644
--- a/xo-reader/src/reader/expect_expr_xs.cpp
+++ b/xo-reader/src/reader/expect_expr_xs.cpp
@@ -13,6 +13,7 @@
 #include "progress_xs.hpp"
 #include "xo/expression/Lambda.hpp"
 #include "xo/expression/Constant.hpp"
+#include "xo/expression/pretty_expression.hpp"
 
 namespace xo {
     using xo::ast::Constant;
diff --git a/xo-reader/src/reader/exprstate.cpp b/xo-reader/src/reader/exprstate.cpp
index af3fc9ff..bf30134d 100644
--- a/xo-reader/src/reader/exprstate.cpp
+++ b/xo-reader/src/reader/exprstate.cpp
@@ -3,9 +3,11 @@
 #include "exprstate.hpp"
 #include "exprstatestack.hpp"
 #include "parserstatemachine.hpp"
+#include "pretty_expression.hpp"
 //#include "formal_arg.hpp"
 #include "xo/expression/Variable.hpp"
 #include "xo/indentlog/print/vector.hpp"
+#include "xo/indentlog/print/pretty_vector.hpp"
 #include <stdexcept>
 //#include "define_xs.hpp"
 //#include "progress_xs.hpp"
diff --git a/xo-reader/src/reader/paren_xs.cpp b/xo-reader/src/reader/paren_xs.cpp
index 8ac163ea..950a1547 100644
--- a/xo-reader/src/reader/paren_xs.cpp
+++ b/xo-reader/src/reader/paren_xs.cpp
@@ -5,6 +5,7 @@
 #include "exprstatestack.hpp"
 #include "progress_xs.hpp"
 #include "expect_expr_xs.hpp"
+#include "xo/expression/pretty_expression.hpp"
 
 namespace xo {
     namespace scm {
diff --git a/xo-reader/src/reader/parser.cpp b/xo-reader/src/reader/parser.cpp
index 45519df3..dfa34658 100644
--- a/xo-reader/src/reader/parser.cpp
+++ b/xo-reader/src/reader/parser.cpp
@@ -7,6 +7,7 @@
 #include "parserstatemachine.hpp"
 #include "define_xs.hpp"
 #include "exprseq_xs.hpp"
+#include "pretty_expression.hpp"
 #include "xo/expression/DefineExpr.hpp"
 #include "xo/expression/Constant.hpp"
 #include "xo/expression/ConvertExpr.hpp"
diff --git a/xo-reader/src/reader/parserstatemachine.cpp b/xo-reader/src/reader/parserstatemachine.cpp
index 005c1af7..34c7cbbe 100644
--- a/xo-reader/src/reader/parserstatemachine.cpp
+++ b/xo-reader/src/reader/parserstatemachine.cpp
@@ -5,6 +5,7 @@
 
 #include "parserstatemachine.hpp"
 #include "exprstatestack.hpp"
+#include "xo/expression/pretty_expression.hpp"
 
 namespace xo {
     using xo::ast::LocalEnv;
diff --git a/xo-reader/src/reader/progress_xs.cpp b/xo-reader/src/reader/progress_xs.cpp
index 5c98ed30..fea536a7 100644
--- a/xo-reader/src/reader/progress_xs.cpp
+++ b/xo-reader/src/reader/progress_xs.cpp
@@ -6,6 +6,7 @@
 #include "parserstatemachine.hpp"
 #include "xo/expression/AssignExpr.hpp"
 #include "xo/expression/Apply.hpp"
+#include "xo/expression/pretty_expression.hpp"
 
 namespace xo {
     using xo::ast::Expression;
diff --git a/xo-reader/src/reader/sequence_xs.cpp b/xo-reader/src/reader/sequence_xs.cpp
index 39e38365..365b9747 100644
--- a/xo-reader/src/reader/sequence_xs.cpp
+++ b/xo-reader/src/reader/sequence_xs.cpp
@@ -6,6 +6,7 @@
 #include "let1_xs.hpp"
 #include "xo/expression/DefineExpr.hpp"
 #include "xo/expression/Sequence.hpp"
+#include "xo/expression/pretty_expression.hpp"
 
 namespace xo {
     using xo::ast::DefineExpr;