From d62ca9f87906be6f046fe9d07afb8bfb69c166e3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?louiz=E2=80=99?= <louiz@louiz.org>
Date: Fri, 16 Mar 2018 01:11:47 +0100
Subject: Use if constexpr to make things a lot more readable

---
 src/database/table.hpp | 44 ++++++++++++++++++++------------------------
 1 file changed, 20 insertions(+), 24 deletions(-)

(limited to 'src/database/table.hpp')

diff --git a/src/database/table.hpp b/src/database/table.hpp
index 680e7cc..eb68418 100644
--- a/src/database/table.hpp
+++ b/src/database/table.hpp
@@ -93,36 +93,32 @@ class Table
  private:
 
   template <std::size_t N=0>
-  typename std::enable_if<N < sizeof...(T), void>::type
-  add_column_if_not_exists(DatabaseEngine& db, const std::set<std::string>& existing_columns)
+  void add_column_if_not_exists(DatabaseEngine& db, const std::set<std::string>& existing_columns)
   {
-    using ColumnType = typename std::remove_reference<decltype(std::get<N>(std::declval<ColumnTypes>()))>::type;
-    if (existing_columns.count(ColumnType::name) == 0)
-      add_column_to_table<ColumnType>(db, this->name);
-    add_column_if_not_exists<N+1>(db, existing_columns);
+    if constexpr(N < sizeof...(T))
+      {
+        using ColumnType = typename std::remove_reference<decltype(std::get<N>(std::declval<ColumnTypes>()))>::type;
+        if (existing_columns.count(ColumnType::name) == 0)
+          add_column_to_table<ColumnType>(db, this->name);
+        add_column_if_not_exists<N + 1>(db, existing_columns);
+      }
   }
-  template <std::size_t N=0>
-  typename std::enable_if<N == sizeof...(T), void>::type
-  add_column_if_not_exists(DatabaseEngine&, const std::set<std::string>&)
-  {}
 
   template <std::size_t N=0>
-  typename std::enable_if<N < sizeof...(T), void>::type
-  add_column_create(DatabaseEngine& db, std::string& str)
+  void add_column_create(DatabaseEngine& db, std::string& str)
   {
-    using ColumnType = typename std::remove_reference<decltype(std::get<N>(std::declval<ColumnTypes>()))>::type;
-    str += ColumnType::name;
-    str += " ";
-    str += ToSQLType<ColumnType>(db);
-    if (N != sizeof...(T) - 1)
-      str += ",";
-
-    add_column_create<N+1>(db, str);
+    if constexpr(N < sizeof...(T))
+      {
+        using ColumnType = typename std::remove_reference<decltype(std::get<N>(std::declval<ColumnTypes>()))>::type;
+        str += ColumnType::name;
+        str += " ";
+        str += ToSQLType<ColumnType>(db);
+        if (N != sizeof...(T) - 1)
+          str += ",";
+
+        add_column_create<N + 1>(db, str);
+      }
   }
-  template <std::size_t N=0>
-  typename std::enable_if<N == sizeof...(T), void>::type
-  add_column_create(DatabaseEngine&, std::string&)
-  { }
 
   const std::string name;
 };
-- 
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