added single-header variant

CMakeLists.txt

 # cmake compatibility issues
-CMAKE_MINIMUM_REQUIRED(VERSION 3.1)
+CMAKE_MINIMUM_REQUIRED(VERSION 3.8)
 
 # project name
 PROJECT(compass CXX)
@@ -25,7 +25,12 @@ SET (COMPASS_ID "${COMPASS_VENDOR_ID}.${PROJECT_NAME}")
 
 option(WITH_CXX11_ABI       "enable _GLIBCXX_USE_CXX11_ABI in GCC 5.0+" ON)
 option(WITH_TESTS           "enable unit tests" ON)
-option(WITH_SINGLE_HEADER   "produce single header file from include/" OFF)
+option(WITH_SINGLE_HEADER   "use single header file from single-header/" OFF)
+option(GENERATE_SINGLE_HEADER   "run pcpp on include/ and produce single-header" OFF)
+
+if(GENERATE_SINGLE_HEADER)
+  set(WITH_SINGLE_HEADER ON CACHED)
+endif()
 
 check_cxx_compiler_flag(-Wl,-Bsymbolic HAS_BSYMBOLIC_COMPILERFLAG)
 check_cxx_compiler_flag("-Xclang -march=native" HAS_XCLANG_COMPILERFLAG)
@@ -48,11 +53,12 @@ set(COMPASS_CMAKE_VERSION_CONFIG_FILE "${COMPASS_CMAKE_CONFIG_DIR}/${PROJECT_NAM
 set(COMPASS_CMAKE_PROJECT_CONFIG_FILE "${COMPASS_CMAKE_CONFIG_DIR}/${PROJECT_NAME}Config.cmake")
 set(COMPASS_CMAKE_PROJECT_TARGETS_FILE "${COMPASS_CMAKE_CONFIG_DIR}/${PROJECT_NAME}Targets.cmake")
 
+
 if (NOT WITH_SINGLE_HEADER)
-    set(COMPASS_INCLUDE_BUILD_DIR "${PROJECT_SOURCE_DIR}/include/")
+    set(COMPASS_INCLUDE_BUILD_DIR "${PROJECT_SOURCE_DIR}/include")
     message(STATUS "Using the multi-header code from ${COMPASS_INCLUDE_BUILD_DIR}")
 else()
-    set(COMPASS_INCLUDE_BUILD_DIR "${PROJECT_SOURCE_DIR}/single_include/")
+    set(COMPASS_INCLUDE_BUILD_DIR "${PROJECT_SOURCE_DIR}/single_include")
     message(STATUS "Using the single-header code from ${COMPASS_INCLUDE_BUILD_DIR}")
 endif()
 
@@ -69,6 +75,30 @@ target_compile_definitions(${COMPASS_TARGET_NAME}
   INTERFACE cxx_std_11
     )
 
+## ============== generate single-header ================
+ if (${GENERATE_SINGLE_HEADER})
+  find_program(PCPP NAMES pcpp PATH ${PCPP_PATH} PATH_SUFFIXES bin NO_DEFAULT_PATH)
+  find_program(PCPP NAMES pcpp)
+  if(EXISTS ${PCPP})
+    message(STATUS "pcpp found at ${PCPP}")
+    if(NOT EXISTS ${COMPASS_INCLUDE_BUILD_DIR})
+      file(MAKE_DIRECTORY ${COMPASS_INCLUDE_BUILD_DIR})
+      message("created ${COMPASS_INCLUDE_BUILD_DIR}")
+    endif()
+
+    execute_process(COMMAND ${PCPP} -o ${COMPASS_INCLUDE_BUILD_DIR}/compass.hpp --line-directive --passthru-defines --passthru-unfound-includes --passthru-unknown-exprs ${PROJECT_SOURCE_DIR}/include/compass.hpp
+      WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
+      RESULT_VARIABLE PCPP_RESULT)
+    if(${PCPP_RESULT} EQUAL 0)
+      message(STATUS "Preprocessed ${PROJECT_SOURCE_DIR}/include/compass.hpp into ${COMPASS_INCLUDE_BUILD_DIR}/compass.hpp")
+    else()
+      message(FATAL_ERROR "Preprocessing ${PROJECT_SOURCE_DIR}/include/compass.hpp into ${COMPASS_INCLUDE_BUILD_DIR}/compass.hpp failed")
+    endif()
+  else()
+    message(FATAL_ERROR "pcpp not found (${PCPP_PATH} ${PCPP_FOUND}), unable to continue in single-header configuration")
+  endif()
+endif()
+
 #target_sources(compass INTERFACE include/compass.hpp)
 
 
@@ -116,7 +146,7 @@ install(
   NAMESPACE ${PROJECT_NAME}::
   DESTINATION ${COMPASS_CONFIG_INSTALL_DIR}
   )
-install(DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/include/"
+install(DIRECTORY "${COMPASS_INCLUDE_BUILD_DIR}"
   DESTINATION include
   FILES_MATCHING
   PATTERN "*.hpp"

tests/CMakeLists.txt

@@ -13,15 +13,23 @@ ExternalProject_Add(
     )
 ExternalProject_Get_Property(catch2 DOWNLOAD_DIR)
 set(CATCH2_HEADER_PATH ${DOWNLOAD_DIR})
-
 message(STATUS "catch2 header file download to ${CATCH2_HEADER_PATH}")
 
 add_library(catcho OBJECT catch.cpp)
 target_include_directories(catcho PUBLIC ${CATCH2_HEADER_PATH})
-
 add_dependencies(catcho catch2)
 
-# prepping tests
+add_executable(test_compass_impl test_compass_impl.cpp $<TARGET_OBJECTS:catcho>)
+target_include_directories(test_compass_impl PRIVATE ${CATCH2_HEADER_PATH} ${COMPASS_INCLUDE_BUILD_DIR})
+
+add_executable(test_bitview test_bitview.cpp $<TARGET_OBJECTS:catcho>)
+target_include_directories(test_bitview PRIVATE ${PROJECT_SOURCE_DIR}/include ${CATCH2_HEADER_PATH})
+
+
+#idea for generating test fixture at cmake-invocation
+#Windows 7: use `wmic cpu GET Name` to obtain clearname of CPU model
+#Linux    : use `lscpu` or `/proc/cpuinfo` to obtain more data about
+#macOS    : not sure yet what to use
 
 cmake_host_system_information(RESULT CURRENT_HOSTNAME QUERY HOSTNAME)
 
@@ -35,33 +43,23 @@ if(${CURRENT_HOSTNAME} MATCHES ".*(falcon2|talisker|schorle|scicomp-pc-3|recover
 
 endif()
 
-#idea for generating test fixture at cmake-invocation
-#Windows 7: use `wmic cpu GET Name` to obtain clearname of CPU model
-#Linux    : use `lscpu` or `/proc/cpuinfo` to obtain more data about
-#macOS    : not sure yet what to use
-add_executable(test_compass_impl test_compass_impl.cpp $<TARGET_OBJECTS:catcho>)
-target_include_directories(test_compass_impl PRIVATE ${CATCH2_HEADER_PATH} ${COMPASS_INCLUDE_BUILD_DIR})
-
-add_executable(test_bitview test_bitview.cpp $<TARGET_OBJECTS:catcho>)
-target_include_directories(test_bitview PRIVATE ${PROJECT_SOURCE_DIR}/include ${CATCH2_HEADER_PATH})
-
 ### test single header
 
-if(WITH_SINGLE_HEADER)
-  find_program(PCPP NAME pcpp HINT ${PCPP_PATH})
-  if(PCPP_FOUND OR EXISTS ${PCPP_PATH})
-    add_custom_target(sh
-      COMMAND pcpp -o ${PROJECT_BINARY_DIR}/tests/compass-sh.hpp --line-directive --passthru-defines --passthru-unfound-includes --passthru-unknown-exprs ${PROJECT_SOURCE_DIR}/include/compass.hpp
-      BYPRODUCTS ${CMAKE_CURRENT_BINARY_DIR}/compass-sh.hpp
-      COMMENT "Preprocessing ${PROJECT_SOURCE_DIR}/include/compass.hpp into ${CMAKE_CURRENT_BINARY_DIR}/tests/compass-sh.hpp ..."
-      USES_TERMINAL)
+# if(WITH_SINGLE_HEADER)
+#   find_program(PCPP NAME pcpp HINT ${PCPP_PATH})
+#   if(PCPP_FOUND OR EXISTS ${PCPP_PATH})
+#     add_custom_target(sh
+#       COMMAND pcpp -o ${PROJECT_BINARY_DIR}/tests/compass-sh.hpp --line-directive --passthru-defines --passthru-unfound-includes --passthru-unknown-exprs ${PROJECT_SOURCE_DIR}/include/compass.hpp
+#       BYPRODUCTS ${CMAKE_CURRENT_BINARY_DIR}/compass-sh.hpp
+#       COMMENT "Preprocessing ${PROJECT_SOURCE_DIR}/include/compass.hpp into ${CMAKE_CURRENT_BINARY_DIR}/tests/compass-sh.hpp ..."
+#       USES_TERMINAL)
 
-    add_executable(test_single_header test_single_header.cpp $<TARGET_OBJECTS:catcho> ${CMAKE_CURRENT_BINARY_DIR}/compass-sh.hpp)
-    add_dependencies(test_single_header sh)
-    target_include_directories(test_single_header PRIVATE ${PROJECT_BINARY_DIR}/tests ${CATCH2_HEADER_PATH})
+#     add_executable(test_single_header test_single_header.cpp $<TARGET_OBJECTS:catcho> ${CMAKE_CURRENT_BINARY_DIR}/compass-sh.hpp)
+#     add_dependencies(test_single_header sh)
+#     target_include_directories(test_single_header PRIVATE ${PROJECT_BINARY_DIR}/tests ${CATCH2_HEADER_PATH})
 
-  else()
-    message(WARNING "pcpp not found ${PCPP_PATH}")
-  endif()
+#   else()
+#     message(WARNING "pcpp not found ${PCPP_PATH}")
+#   endif()
 
-endif()
+# endif()