Add and use a unification_order method

Author: glebm

src/ast.cpp

@@ -505,27 +505,14 @@ namespace Sass {
     return false;
   }
 
-  namespace {
-
-  int SelectorOrder(Simple_Selector_Ptr sel) {
-    if (Cast<Element_Selector>(sel)) return 1;
-    if (Cast<Id_Selector>(sel) || Cast<Class_Selector>(sel)) return 2;
-    if (Cast<Attribute_Selector>(sel)) return 3;
-    if (Cast<Pseudo_Selector>(sel)) return Cast<Pseudo_Selector>(sel)->is_pseudo_element() ? 6 : 4;
-    if (Cast<Wrapped_Selector>(sel)) return 5;
-    return 7;
-  }
-
-  }  // namespace
-
   Compound_Selector_Ptr Simple_Selector::unify_with(Compound_Selector_Ptr rhs)
   {
     const size_t rsize = rhs->length();
     for (size_t i = 0; i < rsize; ++i)
     { if (to_string() == rhs->at(i)->to_string()) return rhs; }
-    const int lhs_order = SelectorOrder(this);
+    const int lhs_order = this->unification_order();
     size_t i = rsize;
-    while (i > 0 && lhs_order < SelectorOrder(rhs->at(i - 1))) --i;
+    while (i > 0 && lhs_order < rhs->at(i - 1)->unification_order()) --i;
     rhs->elements().insert(rhs->elements().begin() + i, this);
     return rhs;
   }

src/ast.hpp

@@ -2215,6 +2215,7 @@ namespace Sass {
     virtual ~Selector() = 0;
     virtual size_t hash() = 0;
     virtual unsigned long specificity() const = 0;
+    virtual int unification_order() const = 0;
     virtual void set_media_block(Media_Block_Ptr mb) {
       media_block(mb);
     }
@@ -2394,6 +2395,10 @@ namespace Sass {
     {
       return 0;
     }
+    int unification_order() const
+    {
+      throw std::runtime_error("unification_order for Parent_Selector is undefined");
+    }
     std::string type() const { return "selector"; }
     static std::string type_name() { return "selector"; }
     ATTACH_AST_OPERATIONS(Parent_Selector)
@@ -2433,6 +2438,10 @@ namespace Sass {
     {
       return Constants::Specificity_Base;
     }
+    int unification_order() const
+    {
+      return Constants::UnificationOrder_Placeholder;
+    }
     virtual bool has_placeholder() {
       return true;
     }
@@ -2457,6 +2466,10 @@ namespace Sass {
       if (name() == "*") return 0;
       else               return Constants::Specificity_Element;
     }
+    int unification_order() const
+    {
+      return Constants::UnificationOrder_Element;
+    }
     virtual Simple_Selector_Ptr unify_with(Simple_Selector_Ptr);
     virtual Compound_Selector_Ptr unify_with(Compound_Selector_Ptr);
     virtual bool operator==(const Simple_Selector& rhs) const;
@@ -2482,6 +2495,10 @@ namespace Sass {
     {
       return Constants::Specificity_Class;
     }
+    int unification_order() const
+    {
+      return Constants::UnificationOrder_Class;
+    }
     virtual Compound_Selector_Ptr unify_with(Compound_Selector_Ptr);
     ATTACH_AST_OPERATIONS(Class_Selector)
     ATTACH_CRTP_PERFORM_METHODS()
@@ -2502,6 +2519,10 @@ namespace Sass {
     {
       return Constants::Specificity_ID;
     }
+    int unification_order() const
+    {
+      return Constants::UnificationOrder_Id;
+    }
     virtual Compound_Selector_Ptr unify_with(Compound_Selector_Ptr);
     ATTACH_AST_OPERATIONS(Id_Selector)
     ATTACH_CRTP_PERFORM_METHODS()
@@ -2538,6 +2559,10 @@ namespace Sass {
     {
       return Constants::Specificity_Attr;
     }
+    int unification_order() const
+    {
+      return Constants::UnificationOrder_Attribute;
+    }
     virtual bool operator==(const Simple_Selector& rhs) const;
     virtual bool operator==(const Attribute_Selector& rhs) const;
     virtual bool operator<(const Simple_Selector& rhs) const;
@@ -2599,6 +2624,12 @@ namespace Sass {
         return Constants::Specificity_Element;
       return Constants::Specificity_Pseudo;
     }
+    int unification_order() const
+    {
+      if (is_pseudo_element())
+        return Constants::UnificationOrder_PseudoElement;
+      return Constants::UnificationOrder_PseudoClass;
+    }
     virtual bool operator==(const Simple_Selector& rhs) const;
     virtual bool operator==(const Pseudo_Selector& rhs) const;
     virtual bool operator<(const Simple_Selector& rhs) const;
@@ -2627,6 +2658,10 @@ namespace Sass {
     virtual bool has_parent_ref() const;
     virtual bool has_real_parent_ref() const;
     virtual unsigned long specificity() const;
+    int unification_order() const
+    {
+      return Constants::UnificationOrder_Wrapped;
+    }
     virtual bool find ( bool (*f)(AST_Node_Obj) );
     virtual bool operator==(const Simple_Selector& rhs) const;
     virtual bool operator==(const Wrapped_Selector& rhs) const;
@@ -2709,6 +2744,10 @@ namespace Sass {
       { sum += (*this)[i]->specificity(); }
       return sum;
     }
+    int unification_order() const
+    {
+      throw std::runtime_error("unification_order for Compound_Selector is undefined");
+    }
 
     virtual bool has_placeholder()
     {
@@ -2837,6 +2876,10 @@ namespace Sass {
       if (tail()) sum += tail()->specificity();
       return sum;
     }
+    int unification_order() const
+    {
+      throw std::runtime_error("unification_order for Complex_Selector is undefined");
+    }
     virtual void set_media_block(Media_Block_Ptr mb) {
       media_block(mb);
       if (tail_) tail_->set_media_block(mb);
@@ -2960,6 +3003,10 @@ namespace Sass {
       }
       return sum;
     }
+    int unification_order() const
+    {
+      throw std::runtime_error("unification_order for Selector_List is undefined");
+    }
     virtual void set_media_block(Media_Block_Ptr mb) {
       media_block(mb);
       for (Complex_Selector_Obj cs : elements()) {

src/constants.cpp

@@ -18,6 +18,15 @@ namespace Sass {
     extern const unsigned long Specificity_Pseudo = 1000;
     extern const unsigned long Specificity_ID = 1000000;
 
+    extern const int UnificationOrder_Element = 1;
+    extern const int UnificationOrder_Id = 2;
+    extern const int UnificationOrder_Class = 2;
+    extern const int UnificationOrder_Attribute = 3;
+    extern const int UnificationOrder_PseudoClass = 4;
+    extern const int UnificationOrder_Wrapped = 5;
+    extern const int UnificationOrder_PseudoElement = 6;
+    extern const int UnificationOrder_Placeholder = 7;
+
     // sass keywords
     extern const char at_root_kwd[]       = "@at-root";
     extern const char import_kwd[]        = "@import";

src/constants.hpp

@@ -18,6 +18,16 @@ namespace Sass {
     extern const unsigned long Specificity_Pseudo;
     extern const unsigned long Specificity_ID;
 
+    // Selector unification order;
+    extern const int UnificationOrder_Element;
+    extern const int UnificationOrder_Id;
+    extern const int UnificationOrder_Class;
+    extern const int UnificationOrder_Attribute;
+    extern const int UnificationOrder_PseudoClass;
+    extern const int UnificationOrder_Wrapped;
+    extern const int UnificationOrder_PseudoElement;
+    extern const int UnificationOrder_Placeholder;
+
     // sass keywords
     extern const char at_root_kwd[];
     extern const char import_kwd[];