Incorporate release date with ensmallen version

HISTORY.md

@@ -1,6 +1,8 @@
 ### ensmallen ?.??.?: "???"
 ###### ????-??-??
 
+ * Add release date to version information. ([#226](https://github.com/mlpack/ensmallen/pull/226))
+
 ### ensmallen 2.14.2: "No Direction Home"
 ###### 2020-08-31
  * Fix implementation of fonesca fleming problem function f1 and f2 

include/ensmallen_bits/ens_version.hpp

@@ -21,7 +21,11 @@
 // (i.e. the version name will be "RC1", "RC2", etc.).  Otherwise the version
 // name will typically be a seemingly arbitrary set of words that does not
 // contain the capitalized string "RC".
-#define ENS_VERSION_NAME "No Direction Home"
+#define ENS_VERSION_NAME  "No Direction Home"
+// Incorporate the date the version was released.
+#define ENS_VERSION_YEAR  "2020"
+#define ENS_VERSION_MONTH "09"
+#define ENS_VERSION_DAY   "05"
 
 namespace ens {
 
@@ -41,6 +45,14 @@ struct version
 
     return ss.str();
   }
+
+  static inline std::string date()
+  {
+    std::stringstream ss;
+    ss << ENS_VERSION_YEAR << '-' << ENS_VERSION_MONTH << '-' << ENS_VERSION_DAY;
+
+    return ss.str();
+  }
 };
 
 } // namespace ens

scripts/ensmallen-release.sh

@@ -124,6 +124,14 @@ new_line="ensmallen $MAJOR.$MINOR.$PATCH: \"$version_name\"";
 sed -i "s/### ensmallen ?.??.?: \"???\"/### $new_line/" HISTORY.md;
 sed -i "s/###### ????-??-??/###### $year-$month-$day/" HISTORY.md;
 
+# Update date in ens_version.hpp
+sed -i 's/ENS_VERSION_YEAR[ ]*\".*\"$/ENS_VERSION_YEAR \"'"$year"'\"/' \
+    include/ensmallen_bits/ens_version.hpp;
+sed -i 's/ENS_VERSION_MONTH[ ]*\".*\"$/ENS_VERSION_MONTH \"'"$month"'\"/' \
+    include/ensmallen_bits/ens_version.hpp;
+sed -i 's/ENS_VERSION_DAY[ ]*\".*\"$/ENS_VERSION_DAY \"'"$day"'\"/' \
+    include/ensmallen_bits/ens_version.hpp;
+
 # Now, we'll do all this on a new release branch.
 git checkout -b release-$MAJOR.$MINOR.$PATCH;