Implement is_superselector sass function

Fixes #1091
Fixes #1063
Fixes #823

Author: mgreter

ast.cpp

@@ -242,7 +242,23 @@ namespace Sass {
     if (!lbase) // no lbase; just see if the left-hand qualifiers are a subset of the right-hand selector
     {
       for (size_t i = 0, L = length(); i < L; ++i)
-      { lset.insert((*this)[i]->perform(&to_string)); }
+      {
+        Selector* lhs = (*this)[i];
+        if (Wrapped_Selector* wrapped = dynamic_cast<Wrapped_Selector*>(lhs)) {
+          if (
+            wrapped->name() == ":matches(" ||
+            wrapped->name() == ":-moz-any("
+          ) {
+          lhs = wrapped->selector();
+          if (Selector_List* list = dynamic_cast<Selector_List*>(lhs)) {
+            if (Compound_Selector* comp = dynamic_cast<Compound_Selector*>(rhs)) {
+              if (list->is_superselector_of(comp)) return true;
+            }
+          }
+          }
+        }
+        lset.insert(lhs->perform(&to_string));
+      }
       for (size_t i = 0, L = rhs->length(); i < L; ++i)
       { rset.insert((*rhs)[i]->perform(&to_string)); }
       return includes(rset.begin(), rset.end(), lset.begin(), lset.end());
@@ -326,8 +342,6 @@ namespace Sass {
 
   bool Complex_Selector::is_superselector_of(Compound_Selector* rhs)
   {
-    if (length() != 1)
-    { return false; }
     return base()->is_superselector_of(rhs);
   }
 
@@ -352,6 +366,16 @@ namespace Sass {
     if (l_len == 1)
     { return lhs->head()->is_superselector_of(rhs->base()); }
 
+    // we have to look one tail deeper, since we cary the
+    // combinator around for it (which is important here)
+    if (rhs->tail() && lhs->tail() && combinator() != Complex_Selector::ANCESTOR_OF) {
+      Complex_Selector* lhs_tail = lhs->tail();
+      Complex_Selector* rhs_tail = rhs->tail();
+      if (lhs_tail->combinator() != rhs_tail->combinator()) return false;
+      if (!lhs_tail->head()->is_superselector_of(rhs_tail->head())) return false;
+    }
+
+
     bool found = false;
     Complex_Selector* marker = rhs;
     for (size_t i = 0, L = rhs->length(); i < L; ++i) {
@@ -493,6 +517,50 @@ namespace Sass {
 #endif
   }
 
+  // it's a superselector if every selector of the right side
+  // list is a superselector of the given left side selector
+  bool Complex_Selector::is_superselector_of(Selector_List *sub)
+  {
+    // Check every rhs selector against left hand list
+    for(size_t i = 0, L = sub->length(); i < L; ++i) {
+      if (!is_superselector_of((*sub)[i])) return false;
+    }
+    return true;
+  }
+
+  // it's a superselector if every selector of the right side
+  // list is a superselector of the given left side selector
+  bool Selector_List::is_superselector_of(Selector_List *sub)
+  {
+    // Check every rhs selector against left hand list
+    for(size_t i = 0, L = sub->length(); i < L; ++i) {
+      if (!is_superselector_of((*sub)[i])) return false;
+    }
+    return true;
+  }
+
+  // it's a superselector if every selector on the right side
+  // is a superselector of any one of the left side selectors
+  bool Selector_List::is_superselector_of(Compound_Selector *sub)
+  {
+    // Check every lhs selector against right hand
+    for(size_t i = 0, L = length(); i < L; ++i) {
+      if ((*this)[i]->is_superselector_of(sub)) return true;
+    }
+    return false;
+  }
+
+  // it's a superselector if every selector on the right side
+  // is a superselector of any one of the left side selectors
+  bool Selector_List::is_superselector_of(Complex_Selector *sub)
+  {
+    // Check every lhs selector against right hand
+    for(size_t i = 0, L = length(); i < L; ++i) {
+      if ((*this)[i]->is_superselector_of(sub)) return true;
+    }
+    return false;
+  }
+
   /* not used anymore - remove?
   Selector_Placeholder* Selector_List::find_placeholder()
   {

ast.hpp

@@ -1943,7 +1943,9 @@ namespace Sass {
         return (*this)[0];
       return 0;
     }
-    bool is_superselector_of(Compound_Selector* rhs);
+    bool is_superselector_of(Compound_Selector* sub);
+    // bool is_superselector_of(Complex_Selector* sub);
+    // bool is_superselector_of(Selector_List* sub);
     virtual unsigned long specificity()
     {
       int sum = 0;
@@ -2000,8 +2002,9 @@ namespace Sass {
     Complex_Selector* context(Context&);
     Complex_Selector* innermost();
     size_t length();
-    bool is_superselector_of(Compound_Selector*);
-    bool is_superselector_of(Complex_Selector*);
+    bool is_superselector_of(Compound_Selector* sub);
+    bool is_superselector_of(Complex_Selector* sub);
+    bool is_superselector_of(Selector_List* sub);
     // virtual Selector_Placeholder* find_placeholder();
     Combinator clear_innermost();
     void set_innermost(Complex_Selector*, Combinator);
@@ -2086,6 +2089,9 @@ namespace Sass {
     : Selector(pstate), Vectorized<Complex_Selector*>(s), wspace_(0)
     { }
     // virtual Selector_Placeholder* find_placeholder();
+    bool is_superselector_of(Compound_Selector* sub);
+    bool is_superselector_of(Complex_Selector* sub);
+    bool is_superselector_of(Selector_List* sub);
     virtual unsigned long specificity()
     {
       unsigned long sum = 0;

context.cpp

@@ -539,6 +539,8 @@ namespace Sass {
     // Misc Functions
     register_function(ctx, inspect_sig, inspect, env);
     register_function(ctx, unique_id_sig, unique_id, env);
+    // Selector functions
+    register_function(ctx, is_superselector_sig, is_superselector, env);
   }
 
   void register_c_functions(Context& ctx, Env* env, Sass_Function_List descrs)

functions.cpp

@@ -1564,6 +1564,20 @@ namespace Sass {
       // return v;
     }
 
+    Signature is_superselector_sig = "is-superselector($super, $sub)";
+    BUILT_IN(is_superselector)
+    {
+      To_String to_string(&ctx, false);
+      Expression*  ex_sup = ARG("$super", Expression);
+      Expression*  ex_sub = ARG("$sub", Expression);
+      string sup_src = ex_sup->perform(&to_string) + "{";
+      string sub_src = ex_sub->perform(&to_string) + "{";
+      Selector_List* sel_sup = Parser::parse_selector(sup_src.c_str(), ctx);
+      Selector_List* sel_sub = Parser::parse_selector(sub_src.c_str(), ctx);
+      bool result = sel_sup->is_superselector_of(sel_sub);
+      return new (ctx.mem) Boolean(pstate, result);
+    }
+
     Signature unique_id_sig = "unique-id()";
     BUILT_IN(unique_id)
     {

functions.hpp

@@ -101,6 +101,7 @@ namespace Sass {
     extern Signature keywords_sig;
     extern Signature set_nth_sig;
     extern Signature unique_id_sig;
+    extern Signature is_superselector_sig;
 
     BUILT_IN(rgb);
     BUILT_IN(rgba_4);
@@ -175,6 +176,7 @@ namespace Sass {
     BUILT_IN(keywords);
     BUILT_IN(set_nth);
     BUILT_IN(unique_id);
+    BUILT_IN(is_superselector);
 
   }
 }

parser.cpp

@@ -40,6 +40,14 @@ namespace Sass {
     return p;
   }
 
+  Selector_List* Parser::parse_selector(const char* src, Context& ctx, ParserState pstate)
+  {
+    Parser p = Parser::from_c_str(src, ctx, pstate);
+    // ToDo: ruby sass errors on parent references
+    // ToDo: remap the source-map entries somehow
+    return p.parse_selector_group();
+  }
+
   bool Parser::peek_newline(const char* start)
   {
     return peek_linefeed(start ? start : position);

parser.hpp

@@ -57,6 +57,8 @@ namespace Sass {
     static Parser from_c_str(const char* src, Context& ctx, ParserState pstate = ParserState("[CSTRING]"));
     static Parser from_c_str(const char* beg, const char* end, Context& ctx, ParserState pstate = ParserState("[CSTRING]"));
     static Parser from_token(Token t, Context& ctx, ParserState pstate = ParserState("[TOKEN]"));
+    // special static parsers to convert strings into certain selectors
+    static Selector_List* parse_selector(const char* src, Context& ctx, ParserState pstate = ParserState("[SELECTOR]"));
 
 #ifdef __clang__