Add custom CMake feature summary

CMakeLists.txt

@@ -58,26 +58,8 @@ set(NLOHMANN_JSON_PKGCONFIG_INSTALL_DIR     "${CMAKE_INSTALL_DATADIR}/pkgconfig"
 
 if (JSON_MultipleHeaders)
     set(NLOHMANN_JSON_INCLUDE_BUILD_DIR "${PROJECT_SOURCE_DIR}/include/")
-    message(STATUS "Using the multi-header code from ${NLOHMANN_JSON_INCLUDE_BUILD_DIR}")
 else()
     set(NLOHMANN_JSON_INCLUDE_BUILD_DIR "${PROJECT_SOURCE_DIR}/single_include/")
-    message(STATUS "Using the single-header code from ${NLOHMANN_JSON_INCLUDE_BUILD_DIR}")
-endif()
-
-if (NOT JSON_ImplicitConversions)
-    message(STATUS "Implicit conversions are disabled")
-endif()
-
-if (JSON_DisableEnumSerialization)
-    message(STATUS "Enum integer serialization is disabled")
-endif()
-
-if (JSON_LegacyDiscardedValueComparison)
-    message(STATUS "Legacy discarded value comparison enabled")
-endif()
-
-if (JSON_Diagnostics)
-    message(STATUS "Diagnostics enabled")
 endif()
 
 if (JSON_SystemInclude)
@@ -195,3 +177,5 @@ if(JSON_Install)
         DESTINATION ${NLOHMANN_JSON_PKGCONFIG_INSTALL_DIR}
     )
 endif()
+
+include(json_summary)

cmake/json_summary.cmake

@@ -0,0 +1,147 @@
+#############################################################################
+# json_feature_summary_begin()
+#
+# Initialize the feature summary buffer.
+#############################################################################
+
+function(json_feature_summary_begin)
+    set(_JSON_FEATURE_SUMMARY_TEXT "" PARENT_SCOPE)
+endfunction()
+
+#############################################################################
+# json_feature_summary_end()
+#
+# Print the feature summary buffer.
+#############################################################################
+
+function(json_feature_summary_end)
+    if(NOT "${_JSON_FEATURE_SUMMARY_TEXT}" STREQUAL "")
+        message(STATUS "${_JSON_FEATURE_SUMMARY_TEXT}")
+    endif()
+
+    unset(_JSON_FEATURE_SUMMARY_TEXT PARENT_SCOPE)
+endfunction()
+
+#############################################################################
+# json_feature(
+#     <var> <text>
+#     [VALUES <value>...]
+#     [NEGATE])
+#
+# Append feature info using <text> and the boolean value of <var> converted
+# to YES/NO.
+#
+# If additional values are given and <var> matches any of them, <var> is not
+# converted to YES/NO.
+#
+# If NEGATE is specified, the boolean value of <var> is negated.
+#
+# ---
+#
+# json_feature(NEWLINE)
+#
+# Append a new line.
+#
+# ---
+#
+# json_feature(RAW <text>)
+#
+# Append raw text <text> to feature summary.
+#############################################################################
+
+function(json_feature)
+    if(NOT DEFINED _JSON_FEATURE_SUMMARY_TEXT)
+        message(FATAL_ERROR "json_feature() called before json_feature_summary_begin()")
+    endif()
+
+    set(var "")
+    set(text "")
+    if(${ARGC} EQUAL 1 OR ${ARGC} GREATER 1)
+        list(GET ARGN 0 var)
+    endif()
+    if(${ARGC} EQUAL 2 OR ${ARGC} GREATER 2)
+        list(GET ARGN 1 text)
+    endif()
+
+    # json_feature(RAW <text>)
+    if("${var}" STREQUAL RAW AND NOT "${text}" STREQUAL "")
+        set(text "   ${text}")
+    # json_feature(NEWLINE)
+    elseif("${var}" STREQUAL NEWLINE AND "${text}" STREQUAL "")
+        # noop
+    # json_feature(<var> <text> ...)
+    elseif(NOT "${var}" STREQUAL "" AND NOT "${text}" STREQUAL "")
+        cmake_parse_arguments(args "NEGATE" "" "VALUES" ${ARGN})
+
+        set(state NO)
+        if(args_VALUES)
+            foreach(value ${args_VALUES})
+                if(${var} STREQUAL value)
+                    set(state ${value})
+                    break()
+                endif()
+            endforeach()
+        elseif(${args_NEGATE} AND NOT ${var} OR ${var})
+            set(state YES)
+        endif()
+        set(text "   ${text} ${state}")
+    else()
+        message(FATAL_ERROR "json_feature() called with incorrect arguments")
+    endif()
+
+    # add preamble if buffer is empty
+    if("${_JSON_FEATURE_SUMMARY_TEXT}" STREQUAL "")
+        set(_JSON_FEATURE_SUMMARY_TEXT "[nohmann_json]: Feature summary:\n")
+    else()
+        set(_JSON_FEATURE_SUMMARY_TEXT "${_JSON_FEATURE_SUMMARY_TEXT}\n")
+    endif()
+
+    # append to buffer
+    set(_JSON_FEATURE_SUMMARY_TEXT "${_JSON_FEATURE_SUMMARY_TEXT}${text}" PARENT_SCOPE)
+endfunction()
+
+#############################################################################
+# print feature summary
+#############################################################################
+
+json_feature_summary_begin()
+
+json_feature(JSON_BuildTests "Build tests?")
+if(JSON_BuildTests)
+    json_feature(JSON_32bitTest "Build the 32bit unit test?" VALUES AUTO ONLY)
+    json_feature(JSON_FastTests "Skip expensive/slow tests?")
+
+    if(JSON_TestDataDirectory)
+        json_feature(RAW "Test data directory: ${JSON_TestDataDirectory}")
+    else()
+        json_feature(RAW "Test data source: ${JSON_TEST_DATA_URL} (v${JSON_TEST_DATA_VERSION})")
+    endif()
+
+    json_feature(JSON_Valgrind "Execute test suite with Valgrind?")
+    if(JSON_Valgrind)
+        string (REPLACE ";" " " memcheck_command "${CMAKE_MEMORYCHECK_COMMAND};${CMAKE_MEMORYCHECK_COMMAND_OPTIONS}")
+        json_feature(RAW "Valgrind command: ${memcheck_command}")
+    endif()
+
+    list(JOIN JSON_TEST_CXX_STANDARDS_FEATURE_INFO " " test_cxx_standards)
+    if(JSON_TEST_CXX_STANDARDS_FORCED)
+        set(test_cxx_standards "${test_cxx_standards} (forced)")
+    endif()
+    json_feature(RAW "Test C++ standards: ${test_cxx_standards}")
+endif()
+
+json_feature(NEWLINE)
+
+json_feature(JSON_Diagnostics "Diagnostics enabled?")
+json_feature(JSON_DisableEnumSerialization "Default integer enum serialization enabled?" NEGATE)
+json_feature(JSON_GlobalUDLs "Define user-defined string literals globally?")
+json_feature(JSON_ImplicitConversions "Implicit conversions enabled?")
+json_feature(JSON_LegacyDiscardedValueComparison "Legacy discarded value comparison enabled?")
+
+json_feature(NEWLINE)
+
+json_feature(JSON_MultipleHeaders "Use the multi-header code?")
+json_feature(RAW "Include directory: ${NLOHMANN_JSON_INCLUDE_BUILD_DIR}")
+json_feature(JSON_SystemInclude "Include as system headers?")
+
+json_feature_summary_end()

tests/CMakeLists.txt

@@ -95,27 +95,23 @@ json_test_set_test_options(test-unicode4 TEST_PROPERTIES TIMEOUT 3000)
 
 if("${JSON_TestStandards}" STREQUAL "")
     set(test_cxx_standards 11 14 17 20 23)
-    unset(test_force)
+    set(test_force "")
 else()
     set(test_cxx_standards ${JSON_TestStandards})
     set(test_force FORCE)
 endif()
 
-# Print selected standards marking unavailable ones with brackets
-set(msg_standards "")
+# create list of selected C++ standards for feature summary
+set(info "")
 foreach(cxx_standard ${test_cxx_standards})
     if(compiler_supports_cpp_${cxx_standard})
-        list(APPEND msg_standards ${cxx_standard})
+        list(APPEND info ${cxx_standard})
     else()
-        list(APPEND msg_standards [${cxx_standard}])
+        list(APPEND info [${cxx_standard}])
     endif()
 endforeach()
-string(JOIN " " msg_standards ${msg_standards})
-set(msg "Testing standards: ${msg_standards}")
-if(test_force)
-    string(APPEND msg " (forced)")
-endif()
-message(STATUS "${msg}")
+set(JSON_TEST_CXX_STANDARDS_FEATURE_INFO "${info}" PARENT_SCOPE)
+set(JSON_TEST_CXX_STANDARDS_FORCED ${test_force} PARENT_SCOPE)
 
 # *DO* use json_test_set_test_options() above this line