Add version macro FMT_VERSION (#411)

CMakeLists.txt

@@ -9,12 +9,22 @@ if (CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
   set(MASTER_PROJECT ON)
 endif ()
 
+# Joins arguments and places the results in ${result_var}.
+function(join result_var)
+  set(result )
+  foreach (arg ${ARGN})
+    set(result "${result}${arg}")
+  endforeach ()
+  set(${result_var} "${result}" PARENT_SCOPE)
+endfunction()
+
 # Set the default CMAKE_BUILD_TYPE to Release.
 # This should be done before the project command since the latter can set
 # CMAKE_BUILD_TYPE itself (it does so for nmake).
 if (NOT CMAKE_BUILD_TYPE)
-  set(CMAKE_BUILD_TYPE Release CACHE STRING
-    "Choose the type of build, options are: None(CMAKE_CXX_FLAGS or CMAKE_C_FLAGS used) Debug Release RelWithDebInfo MinSizeRel.")
+  join(doc "Choose the type of build, options are: None(CMAKE_CXX_FLAGS or "
+           "CMAKE_C_FLAGS used) Debug Release RelWithDebInfo MinSizeRel.")
+  set(CMAKE_BUILD_TYPE Release CACHE STRING ${doc})
 endif ()
 
 option(FMT_PEDANTIC "Enable extra warnings and expensive tests." OFF)
@@ -27,14 +37,18 @@ option(FMT_USE_CPP14 "Enable the addition of C++14 compiler flags." ON)
 
 project(FMT)
 
-# Starting with cmake 3.0 VERSION is part of the project command.
-set(FMT_VERSION 3.1.0)
-if (NOT FMT_VERSION MATCHES "^([0-9]+).([0-9]+).([0-9]+)$")
-  message(FATAL_ERROR "Invalid version format ${FMT_VERSION}.")
+# Get version from core.h
+file(READ include/fmt/core.h core_h)
+if (NOT core_h MATCHES "FMT_VERSION ([0-9]+)([0-9][0-9])([0-9][0-9])")
+  message(FATAL_ERROR "Cannot get FMT_VERSION from core.h.")
 endif ()
-set(CPACK_PACKAGE_VERSION_MAJOR ${CMAKE_MATCH_1})
-set(CPACK_PACKAGE_VERSION_MINOR ${CMAKE_MATCH_2})
-set(CPACK_PACKAGE_VERSION_PATCH ${CMAKE_MATCH_3})
+# Use math to skip leading zeros if any.
+math(EXPR CPACK_PACKAGE_VERSION_MAJOR ${CMAKE_MATCH_1})
+math(EXPR CPACK_PACKAGE_VERSION_MINOR ${CMAKE_MATCH_2})
+math(EXPR CPACK_PACKAGE_VERSION_PATCH ${CMAKE_MATCH_3})
+join(FMT_VERSION ${CPACK_PACKAGE_VERSION_MAJOR}.${CPACK_PACKAGE_VERSION_MINOR}.
+                 ${CPACK_PACKAGE_VERSION_PATCH})
+message(STATUS "Version: ${FMT_VERSION}")
 
 message(STATUS "Build type: ${CMAKE_BUILD_TYPE}")
 

include/fmt/core.h

@@ -15,6 +15,9 @@
 #include <string>
 #include <type_traits>
 
+// The fmt library version in the form major * 10000 + minor * 100 + patch.
+#define FMT_VERSION 50000
+
 #ifdef __has_feature
 # define FMT_HAS_FEATURE(x) __has_feature(x)
 #else