Move implementation to library

dune/solvers/CMakeLists.txt

 dune_add_library("dunesolvers"
+    iterationsteps/blockgssteps.cc
     solvers/criterion.cc)
 
 dune_register_package_flags(LIBRARIES dunesolvers)

dune/solvers/iterationsteps/blockgssteps.cc

+#include <algorithm>
+
+#include "blockgssteps.hh"
+
+namespace Dune {
+namespace Solvers {
+  namespace BlockGS {
+    std::istream& operator>>(std::istream& lhs, Direction& t) {
+      std::string s;
+      lhs >> s;
+      std::transform(s.begin(), s.end(), s.begin(), ::tolower);
+
+      if (s == "forward")
+        t = Direction::FORWARD;
+      else if (s == "backward")
+        t = Direction::BACKWARD;
+      else if (s == "symmetric")
+        t = Direction::SYMMETRIC;
+      else
+        lhs.setstate(std::ios_base::failbit);
+      return lhs;
+    }
+
+    std::istream& operator>>(std::istream& lhs, BlockGSType& t) {
+      std::string s;
+      lhs >> s;
+      std::transform(s.begin(), s.end(), s.begin(), ::tolower);
+
+      if (s == "direct")
+        t = BlockGSType::Direct;
+      else if (s == "ldlt")
+        t = BlockGSType::LDLt;
+      else if (s == "cg")
+        t = BlockGSType::CG;
+      else
+        lhs.setstate(std::ios_base::failbit);
+      return lhs;
+    }
+  }
+}
+}

dune/solvers/iterationsteps/blockgssteps.hh

 #ifndef DUNE_SOLVERS_ITERATIONSTEPS_BLOCKGSSTEPS_HH
 #define DUNE_SOLVERS_ITERATIONSTEPS_BLOCKGSSTEPS_HH
 
-#include <algorithm>
 #include <functional>
 
 #include <dune/common/parametertree.hh>
@@ -20,21 +19,7 @@ enum class Direction { FORWARD, BACKWARD, SYMMETRIC };
 /**
  * @brief Provides support to parse the @Direction enum.
  */
-std::istream& operator>>(std::istream& lhs, Direction& t) {
-  std::string s;
-  lhs >> s;
-  std::transform(s.begin(), s.end(), s.begin(), ::tolower);
-
-  if (s == "forward")
-    t = Direction::FORWARD;
-  else if (s == "backward")
-    t = Direction::BACKWARD;
-  else if (s == "symmetric")
-    t = Direction::SYMMETRIC;
-  else
-    lhs.setstate(std::ios_base::failbit);
-  return lhs;
-}
+std::istream& operator>>(std::istream& lhs, Direction& t);
 
 /**
  * \brief Iterates over all rows i and updates the i-th component by solving
@@ -293,21 +278,7 @@ enum class BlockGSType { Direct, LDLt, CG };
 /**
  * @brief Provides support to parse the @BlockGSType enum.
  */
-std::istream& operator>>(std::istream& lhs, BlockGSType& t) {
-  std::string s;
-  lhs >> s;
-  std::transform(s.begin(), s.end(), s.begin(), ::tolower);
-
-  if (s == "direct")
-    t = BlockGSType::Direct;
-  else if (s == "ldlt")
-    t = BlockGSType::LDLt;
-  else if (s == "cg")
-    t = BlockGSType::CG;
-  else
-    lhs.setstate(std::ios_base::failbit);
-  return lhs;
-}
+std::istream& operator>>(std::istream& lhs, BlockGSType& t);
 
 /**
  * @brief The BlockGSStepFactory struct allows to conveniently construct various