Implement is_superselector sass function [RFC] [WIP]

Based on sass#1064
mgreter · May 12, 2015 · 1de0132 · 1de0132
1 parent 28ee088
commit 1de0132
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Showing 7 changed files with 51 additions and 0 deletions.
diff --git a/ast.cpp b/ast.cpp
@@ -493,6 +493,26 @@ namespace Sass {
 #endif
   }
 
+  bool Selector_List::is_superselector_of(Sass::Selector_List *rhs) {
+    // For every selector in RHS, see if it matches /any/ of our selectors
+    for(size_t rhs_i = 0, rhs_L = rhs->length(); rhs_i < rhs_L; ++rhs_i) {
+      Complex_Selector* seq1 = (*rhs)[rhs_i];
+      bool any = false;
+      for (size_t lhs_i = 0, lhs_L = length(); lhs_i < lhs_L; ++lhs_i) {
+        Complex_Selector* seq2 = (*this)[lhs_i];
+        bool is_superselector = seq2->is_superselector_of(seq1);
+        if( is_superselector ) {
+          any = true;
+          break;
+        }
+      }
+      if(!any) {
+        return false;
+      }
+    }
+    return true;
+  }
+
   /* not used anymore - remove?
   Selector_Placeholder* Selector_List::find_placeholder()
   {

diff --git a/ast.hpp b/ast.hpp
@@ -2086,6 +2086,7 @@ namespace Sass {
     : Selector(pstate), Vectorized<Complex_Selector*>(s), wspace_(0)
     { }
     // virtual Selector_Placeholder* find_placeholder();
+    bool is_superselector_of(Selector_List* other);
     virtual unsigned long specificity()
     {
       unsigned long sum = 0;

diff --git a/context.cpp b/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)

diff --git a/functions.cpp b/functions.cpp
@@ -1564,6 +1564,20 @@ namespace Sass {
       // return v;
     }
 
+    Signature is_superselector_sig = "is-superselector($super, $sub)";
+    BUILT_IN(is_superselector)
+    {
+      To_String to_string(&ctx, false);
+      Expression* ex_sub = ARG("$sub", Expression);
+      Expression* ex_sup = ARG("$super", Expression);
+      string sub_src = ex_sub->perform(&to_string) + "{";
+      string sup_src = ex_sup->perform(&to_string) + "{";
+      Complex_Selector* sel_sub = Parser::parse_complex_selector(sub_src.c_str(), ctx);
+      Complex_Selector* sel_sup = Parser::parse_complex_selector(sup_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)
     {

diff --git a/functions.hpp b/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);
 
   }
 }

diff --git a/parser.cpp b/parser.cpp
@@ -40,6 +40,16 @@ namespace Sass {
     return p;
   }
 
+  Complex_Selector* Parser::parse_complex_selector(const char* src, Context& ctx)
+  {
+    Parser p = Parser::from_c_str(src, ctx, ParserState("sel", src, 0));
+    // if(contextualize.parent) {
+    //   p.block_stack.push_back(contextualize.parent->last_block());
+    //   p.last_media_block = contextualize.parent->media_block();
+    // }
+    return p.parse_selector_combination();
+  }
+
   bool Parser::peek_newline(const char* start)
   {
     return peek_linefeed(start ? start : position);

diff --git a/parser.hpp b/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 Complex_Selector* parse_complex_selector(const char* src, Context& ctx);
 
 #ifdef __clang__