2 files changed, 37 insertions, 0 deletions
diff --git a/src/generic/problemresolver/tier_operation.cc b/src/generic/problemresolver/tier_operation.cc
index 4b619ccf..786c2a9a 100644
--- a/src/generic/problemresolver/tier_operation.cc
+++ b/src/generic/problemresolver/tier_operation.cc
@@ -20,6 +20,8 @@
 
 #include "tier_operation.h"
 
+#include <ostream>
+
 tier tier_operation::levelwise_maximum(const tier &t1, const tier &t2)
 {
   const int out_structural_level =
@@ -123,3 +125,30 @@ tier tier_operation::apply(const tier &t) const
   const tier increased = levelwise_maximum(t, increase_levels);
   return levelwise_add(t, add_levels);
 }
+
+void tier_operation::dump(std::ostream &out) const
+{
+  out << "(";
+
+  bool first = true;
+
+  if(increase_levels != tier())
+    {
+      out << "increase: " << increase_levels;
+      first = false;
+    }
+
+  if(add_levels != tier(0))
+    {
+      if(first)
+        out << ", ";
+      out << "add: " << add_levels;
+    }
+}
+
+std::ostream &operator<<(std::ostream &out, const tier_operation &t)
+{
+  t.dump(out);
+
+  return out;
+}
diff --git a/src/generic/problemresolver/tier_operation.h b/src/generic/problemresolver/tier_operation.h
index 57be296c..8ad5dc67 100644
--- a/src/generic/problemresolver/tier_operation.h
+++ b/src/generic/problemresolver/tier_operation.h
@@ -23,6 +23,8 @@
 #include "exceptions.h"
 #include "tier.h"
 
+#include <iosfwd>
+
 /** \brief A tier operation describes how any solution's tier will
  * change as a result of adding a choice.
  *
@@ -149,6 +151,12 @@ public:
    *  \param t  The tier that this operation should modify.
    */
   tier apply(const tier &t) const;
+
+  /** \brief Write a description of a tier operation to an ostream.
+   */
+  void dump(std::ostream &out) const;
 };
 
+std::ostream &operator<<(std::ostream &out, const tier_operation &t);
+
 #endif // TIER_OPERATION_H