diff --git a/src/include/base/types.h b/src/include/base/types.h
index 674f58b..511bd90 100644
--- a/src/include/base/types.h
+++ b/src/include/base/types.h
@@ -81,42 +81,42 @@ namespace CNORXZ
     template <typename T>
     class Allocator;
 
-    // definition: ranges/xfor/pos_type.h
+    // definition: ranges/xpr/pos_type.h
     template <class PosT>
     class CPosInterface;
 
-    // definition: ranges/xfor/vpos_type.h
+    // definition: ranges/xpr/vpos_type.h
     class VPosBase;
 
-    // definition: ranges/xfor/vpos_type.h
+    // definition: ranges/xpr/vpos_type.h
     template <class PosT>
     class VPos;
 
-    // definition: ranges/xfor/vpos_type.h
+    // definition: ranges/xpr/vpos_type.h
     template <class PosT>
     class VPosRef;
 
-    // definition: ranges/xfor/pos_type.h
+    // definition: ranges/xpr/pos_type.h
     class UPos;
 
-    // definition: ranges/xfor/pos_type.h
+    // definition: ranges/xpr/pos_type.h
     template <SizeT N>
     class SPos;
 
-    // definition: ranges/xfor/pos_type.h
+    // definition: ranges/xpr/pos_type.h
     class FPos;
 
-    // definition: ranges/xfor/pos_type.h
+    // definition: ranges/xpr/pos_type.h
     template <SizeT N, SizeT... Ms>
     class SFPos;
 
-    // definition: ranges/xfor/pos_type.h
+    // definition: ranges/xpr/pos_type.h
     class DPos;
 
-    // definition: ranges/xfor/pos_type.h
+    // definition: ranges/xpr/pos_type.h
     class DPosRef;
 
-    // definition: ranges/xfor/pos_type.h
+    // definition: ranges/xpr/pos_type.h
     template <class PosT1, class PosT2>
     class MPos;
 
diff --git a/src/include/operation/cxz_operation.cc.h b/src/include/operation/cxz_operation.cc.h
index 52b2fa6..6252602 100644
--- a/src/include/operation/cxz_operation.cc.h
+++ b/src/include/operation/cxz_operation.cc.h
@@ -1,6 +1,6 @@
 
 #include "cxz_operation.h"
-#include "xfor/exttype.h"
+#include "xpr/pos_type.h"
 #include "ranges/range_helper.h"
 
 
diff --git a/src/include/ranges/crange.h b/src/include/ranges/crange.h
index be29515..3883692 100644
--- a/src/include/ranges/crange.h
+++ b/src/include/ranges/crange.h
@@ -5,7 +5,6 @@
 #include "base/base.h"
 #include "ranges/index_base.h"
 #include "ranges/range_base.h"
-//#include "xfor/for_type.h"
 
 namespace CNORXZ
 {
diff --git a/src/include/ranges/prange.h b/src/include/ranges/prange.h
index c1b128c..c6a8e1c 100644
--- a/src/include/ranges/prange.h
+++ b/src/include/ranges/prange.h
@@ -13,7 +13,7 @@
 #include "ranges/x_to_string.h"
 #include "ranges/type_map.h"
 
-#include "xfor/for_type.h"
+#include "xpr/for_type.h"
 
 namespace CNORXZ
 {
diff --git a/src/include/ranges/urange.h b/src/include/ranges/urange.h
index 0773621..912317a 100644
--- a/src/include/ranges/urange.h
+++ b/src/include/ranges/urange.h
@@ -6,7 +6,7 @@
 #include "base/base.h"
 #include "ranges/index_base.h"
 #include "ranges/range_base.h"
-#include "xfor/for_type.h"
+#include "xpr/for_type.h"
 
 namespace CNORXZ
 {
diff --git a/src/include/ranges/xfor/for_type.h b/src/include/ranges/xpr/for_type.h
similarity index 100%
rename from src/include/ranges/xfor/for_type.h
rename to src/include/ranges/xpr/for_type.h
diff --git a/src/include/ranges/xfor/for_utils.h b/src/include/ranges/xpr/for_utils.h
similarity index 100%
rename from src/include/ranges/xfor/for_utils.h
rename to src/include/ranges/xpr/for_utils.h
diff --git a/src/include/ranges/xfor/iloop.h b/src/include/ranges/xpr/iloop.h
similarity index 100%
rename from src/include/ranges/xfor/iloop.h
rename to src/include/ranges/xpr/iloop.h
diff --git a/src/include/ranges/xfor/pos_type.cc.h b/src/include/ranges/xpr/pos_type.cc.h
similarity index 100%
rename from src/include/ranges/xfor/pos_type.cc.h
rename to src/include/ranges/xpr/pos_type.cc.h
diff --git a/src/include/ranges/xfor/pos_type.h b/src/include/ranges/xpr/pos_type.h
similarity index 100%
rename from src/include/ranges/xfor/pos_type.h
rename to src/include/ranges/xpr/pos_type.h
diff --git a/src/include/ranges/xfor/vpos_type.cc.h b/src/include/ranges/xpr/vpos_type.cc.h
similarity index 100%
rename from src/include/ranges/xfor/vpos_type.cc.h
rename to src/include/ranges/xpr/vpos_type.cc.h
diff --git a/src/include/ranges/xfor/vpos_type.h b/src/include/ranges/xpr/vpos_type.h
similarity index 100%
rename from src/include/ranges/xfor/vpos_type.h
rename to src/include/ranges/xpr/vpos_type.h
diff --git a/src/include/ranges/xfor/xf.h b/src/include/ranges/xpr/xfor.h
similarity index 100%
rename from src/include/ranges/xfor/xf.h
rename to src/include/ranges/xpr/xfor.h
diff --git a/src/include/ranges/xfor/xfor.cc.h b/src/include/ranges/xpr/xpr.cc.h
similarity index 100%
rename from src/include/ranges/xfor/xfor.cc.h
rename to src/include/ranges/xpr/xpr.cc.h
diff --git a/src/include/ranges/xfor/xfor.h b/src/include/ranges/xpr/xpr.h
similarity index 69%
rename from src/include/ranges/xfor/xfor.h
rename to src/include/ranges/xpr/xpr.h
index 5fef8ae..591b196 100644
--- a/src/include/ranges/xfor/xfor.h
+++ b/src/include/ranges/xpr/xpr.h
@@ -2,4 +2,4 @@
 #include "vpos_type.h"
 #include "pos_type.h"
 
-#include "xfor.cc.h"
+#include "xpr.cc.h"
diff --git a/src/include/utils/helper_tools.h b/src/include/utils/helper_tools.h
index dc1aab1..403ef70 100644
--- a/src/include/utils/helper_tools.h
+++ b/src/include/utils/helper_tools.h
@@ -7,7 +7,7 @@
 #include <ostream>
 #include "map_range.h"
 #include <functional>
-#include "xfor/iloop.h"
+#include "xpr/iloop.h"
 
 namespace CNORXZ
 {
diff --git a/src/tests/CMakeLists.txt b/src/tests/CMakeLists.txt
index 941f1c2..00439dc 100644
--- a/src/tests/CMakeLists.txt
+++ b/src/tests/CMakeLists.txt
@@ -12,10 +12,10 @@ add_library(test_lib STATIC ${test_SOURCES})
 #target_link_libraries(iutest ${GTEST_BOTH_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT} cnorxz)
 #add_test(NAME iutest COMMAND iutest)
 
-add_executable(xfutest xfor_unit_test.cc)
-add_dependencies(xfutest cnorxz)
-target_link_libraries(xfutest ${GTEST_BOTH_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT} cnorxz test_lib)
-add_test(NAME xfutest COMMAND xfutest)
+add_executable(xprutest xpr_unit_test.cc)
+add_dependencies(xprutest cnorxz)
+target_link_libraries(xprutest ${GTEST_BOTH_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT} cnorxz test_lib)
+add_test(NAME xprutest COMMAND xprutest)
 
 add_executable(rutest range_unit_test.cc)
 add_dependencies(rutest cnorxz)
diff --git a/src/tests/xfor_unit_test.cc b/src/tests/xpr_unit_test.cc
similarity index 99%
rename from src/tests/xfor_unit_test.cc
rename to src/tests/xpr_unit_test.cc
index 6095c8a..1eabe73 100644
--- a/src/tests/xfor_unit_test.cc
+++ b/src/tests/xpr_unit_test.cc
@@ -1,7 +1,7 @@
 
 #include "gtest/gtest.h"
 
-#include "ranges/xfor/xfor.h"
+#include "ranges/xpr/xpr.h"
 
 namespace
 {