From ff785188f943c0b0ab6a39aec4cf3ca4c54a2d95 Mon Sep 17 00:00:00 2001
From: Tycho <work.tycho+git@gmail.com>
Date: Tue, 10 Mar 2015 22:19:03 +0000
Subject: Fixed Sequence Generator for IntGen

---
 src/Generating/BioGen.cpp |  6 +++---
 src/Generating/IntGen.h   | 30 +++++++++++++++++++++---------
 2 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/src/Generating/BioGen.cpp b/src/Generating/BioGen.cpp
index a830f6a43..c9561cc09 100644
--- a/src/Generating/BioGen.cpp
+++ b/src/Generating/BioGen.cpp
@@ -1000,9 +1000,9 @@ public:
 			std::make_shared<cIntGenReplaceRandomly<6>> (a_Seed + 101, bgIce, bgTemperate, 150,
 			std::make_shared<cIntGenAddIslands     <6>> (a_Seed + 2000, 200,
 			std::make_shared<cIntGenSetRandomly    <6>> (a_Seed + 9, 50, bgOcean,
-			std::make_shared<cIntGenZoom           <6>> (a_Seed + 10,
-			std::make_shared<cIntGenLandOcean      <5>> (a_Seed + 100, 30
-		)))))))))))))))))))))))))))))));
+			std::make_shared<cIntGenLandOcean      <5>> (a_Seed + 100, 30)
+			>> MakeIntGen<cIntGenZoom           <6>> (a_Seed + 10)
+		)))))))))))))))))))))))))))));
 
 		m_Gen =
 			std::make_shared<cIntGenSmooth   <16>>(a_Seed,
diff --git a/src/Generating/IntGen.h b/src/Generating/IntGen.h
index 4fce3ba08..1ffc15c6b 100644
--- a/src/Generating/IntGen.h
+++ b/src/Generating/IntGen.h
@@ -70,15 +70,20 @@ public:
 	
 };
 
-template<size_t size, class... Args>
-struct PackToInt
-{
-	enum
-	{
-		value = size - sizeof...(Args),
-	};
+// Code adapted from http://stackoverflow.com/questions/7858817/unpacking-a-tuple-to-call-a-matching-function-pointer
+
+template<int ...>
+struct seq { };
+
+template<int N, int ...S>
+struct gens : gens<N-1, N-1, S...> { };
+
+template<int ...S>
+struct gens<0, S...> {
+  typedef seq<S...> type;
 };
 
+
 template<class Gen, class... Args>
 class cIntGenFactory
 {
@@ -91,16 +96,23 @@ public:
 		m_args(std::make_tuple<Args...>(std::forward<Args>(a_args)...))
 	{
 	}
-
+	
 	template <class LhsGen>
 	std::shared_ptr<Gen> construct(LhsGen&& lhs)
 	{
-		return std::make_shared<Gen>(std::get<PackToInt<sizeof...(Args), Args>::value>(m_args)..., std::forward<LhsGen>(lhs));
+		return construct_impl<LhsGen>(std::forward<LhsGen>(lhs), typename gens<sizeof...(Args)>::type());
 	}
 
+
 private:
 	std::tuple<Args...> m_args;
 	
+	template <class LhsGen, int... S>
+	std::shared_ptr<Gen> construct_impl(LhsGen&& lhs, seq<S...>)
+	{
+		return std::make_shared<Gen>(std::get<S>(m_args)..., std::forward<LhsGen>(lhs));
+	}
+	
 };
 
 template<class T, class RhsGen, class... Args>
-- 
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