Re-apply "Use if constexpr to make things a lot more readable"c++17

This reverts commit d0e3c71b91f1a1c1780158789fd42b8ac7209495.

1 files changed, 9 insertions, 12 deletions

diff --git a/src/database/index.hpp b/src/database/index.hpp
index 30766ab..094a36a 100644
--- a/src/database/index.hpp
+++ b/src/database/index.hpp
@@ -8,19 +8,16 @@
 namespace
 {
 template <std::size_t N=0, typename... T>
-typename std::enable_if<N == sizeof...(T), void>::type
-add_column_name(std::string&)
-{ }
-
-template <std::size_t N=0, typename... T>
-typename std::enable_if<N < sizeof...(T), void>::type
-add_column_name(std::string& out)
+void add_column_name(std::string& out)
 {
-  using ColumnType = typename std::remove_reference<decltype(std::get<N>(std::declval<std::tuple<T...>>()))>::type;
-  out += ColumnType::name;
-  if (N != sizeof...(T) - 1)
-    out += ",";
-  add_column_name<N+1, T...>(out);
+  if constexpr(N < sizeof...(T))
+    {
+      using ColumnType = typename std::remove_reference<decltype(std::get<N>(std::declval<std::tuple<T...>>()))>::type;
+      out += ColumnType::name;
+      if (N != sizeof...(T) - 1)
+        out += ",";
+      add_column_name<N + 1, T...>(out);
+    }
 }
 }