Started work on refactoring precedence handling. Need to try and preserver the tree shape it forms, rather than a simple case of monotonically increasing precen

I mean decreasing precedence.

include/XSLT/impl/xslt_precedence.hpp

@@ -0,0 +1,50 @@
+#ifndef ARABICA_XSLT_PRECEDENCE_HPP
+#define ARABICA_XSLT_PRECEDENCE_HPP
+
+class Precedence
+{
+public:
+  Precedence() : 
+    precedence_()
+  { 
+  } // Precedence
+
+  Precedence(const Precedence& rhs) : 
+    precedence_(rhs.precedence_)
+  { 
+  } // Precedence
+
+private:
+  Precedence(const std::vector<int> precedence) : 
+    precedence_(precedence)
+  {
+  } // Precedence
+
+public:
+  ~Precedence() { }
+
+  bool operator==(const Precedence& rhs) const 
+  { 
+    return precedence_ == rhs.precedence_;
+  } // operator==
+
+  Precedence& operator=(const Precedence& rhs) 
+  { 
+    std::vector<int> other(rhs.precedence_);
+
+    precedence_.swap(other);
+    return *this;
+  } // operator=
+
+  Precedence nextGeneration(int p) const
+  {
+    Precedence next(precedence_);
+    next.precedence_.push_back(p);
+    return next;
+  } // nextGeneration
+
+private:
+  std::vector<int> precedence_;  
+}; // class Precedence
+
+#endif

include/XSLT/impl/xslt_template.hpp

@@ -2,6 +2,7 @@
 #define ARABICA_XSLT_TEMPLATE_HPP
 
 #include "xslt_item.hpp"
+#include "xslt_precedence.hpp"
 
 namespace Arabica
 {
@@ -12,8 +13,8 @@ class Template : public ItemContainer
 {
 public:
   Template(const std::pair<std::string, std::string>& name,
-	         const std::pair<std::string, std::string>& mode,
+	   const std::pair<std::string, std::string>& mode,
-	         const std::string& priority) :
+	   const std::string& priority) :
     matches_(),
     name_(name),
     mode_(mode)