From 158a5af1d77ffcf0a5657ee0bcbb55e8a269424b Mon Sep 17 00:00:00 2001
From: Eric Kimn <ekimn@apple.com>
Date: Thu, 5 Feb 2015 05:15:28 -0800
Subject: [PATCH] Support parent selector & in values / and/or interpolations
 #548

---
 ast.hpp      |  7 ++++---
 eval.cpp     |  5 +++++
 eval.hpp     |  1 +
 expand.cpp   | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
 parser.cpp   |  4 ++++
 prelexer.cpp |  3 +++
 prelexer.hpp |  1 +
 7 files changed, 66 insertions(+), 4 deletions(-)

diff --git a/ast.hpp b/ast.hpp
index 7281b384a9..d2ca9af6a4 100644
--- a/ast.hpp
+++ b/ast.hpp
@@ -85,6 +85,7 @@ namespace Sass {
       STRING,
       LIST,
       MAP,
+	  SELECTOR,
       NULL_VAL,
       NUM_TYPES
     };
@@ -1685,13 +1686,13 @@ namespace Sass {
   /////////////////////////////////////////
   // Abstract base class for CSS selectors.
   /////////////////////////////////////////
-  class Selector : public AST_Node {
+  class Selector : public Expression {
     ADD_PROPERTY(bool, has_reference);
     ADD_PROPERTY(bool, has_placeholder);
   public:
     Selector(ParserState pstate, bool r = false, bool h = false)
-    : AST_Node(pstate), has_reference_(r), has_placeholder_(h)
-    { }
+    : Expression(pstate), has_reference_(r), has_placeholder_(h)
+  {  concrete_type(SELECTOR); }
     virtual ~Selector() = 0;
     virtual Selector_Placeholder* find_placeholder();
     virtual int specificity() { return Constants::SPECIFICITY_BASE; }
diff --git a/eval.cpp b/eval.cpp
index cf4979c749..c0e9d97358 100644
--- a/eval.cpp
+++ b/eval.cpp
@@ -809,6 +809,11 @@ namespace Sass {
                                                 e->is_interpolated());
   }
 
+  Expression* Eval::operator()(Selector_Reference* e)
+  {
+	  return e;
+  }
+
   Expression* Eval::operator()(Null* n)
   {
     return n;
diff --git a/eval.hpp b/eval.hpp
index e3a2fed59c..3ea0252543 100644
--- a/eval.hpp
+++ b/eval.hpp
@@ -55,6 +55,7 @@ namespace Sass {
     Expression* operator()(String_Constant*);
     Expression* operator()(Media_Query*);
     Expression* operator()(Media_Query_Expression*);
+    Expression* operator()(Selector_Reference*);
     Expression* operator()(At_Root_Expression*);
     Expression* operator()(Feature_Query*);
     Expression* operator()(Feature_Query_Condition*);
diff --git a/expand.cpp b/expand.cpp
index e9e7d25514..5016ede01e 100644
--- a/expand.cpp
+++ b/expand.cpp
@@ -212,7 +212,54 @@ namespace Sass {
       if (!a->is_guarded() || v->concrete_type() == Expression::NULL_VAL) (*env)[var] = a->value()->perform(eval->with(env, backtrace));
     }
     else {
-      env->current_frame()[var] = a->value()->perform(eval->with(env, backtrace));
+      Selector_Reference* v = static_cast<Selector_Reference*> (a->value ());
+      if (v->concrete_type () == Expression::SELECTOR) {
+	bool old_in_at_root = in_at_root;
+	in_at_root = false;
+	Contextualize* contextual = contextualize->with (
+	    selector_stack.back (), env, backtrace);
+	if (old_in_at_root && !v->has_reference ())
+	  contextual = contextualize->with (at_root_selector_stack.back (),
+					    env, backtrace);
+
+	Selector* sel_ctx = v->perform (contextual);
+
+	Inspect isp (0);
+	sel_ctx->perform (&isp);
+	string str = isp.get_buffer ();
+	str += ";";
+
+	Parser p (ctx, ParserState ("[REPARSE]", 0));
+	p.source = str.c_str ();
+	p.position = str.c_str ();
+	p.end = str.c_str () + strlen (str.c_str ());
+	Selector_List* sel_lst = p.parse_selector_group ();
+	sel_lst->pstate (isp.source_map.remap (sel_lst->pstate ()));
+
+	for (size_t i = 0; i < sel_lst->length (); i++) {
+	  Complex_Selector* pIter = (*sel_lst)[i];
+	  while (pIter) {
+	    Compound_Selector* pHead = pIter->head ();
+	    pIter->pstate (isp.source_map.remap (pIter->pstate ()));
+	    if (pHead) {
+	      pHead->pstate (isp.source_map.remap (pHead->pstate ()));
+	      (*pHead)[0]->pstate (
+		  isp.source_map.remap ((*pHead)[0]->pstate ()));
+	    }
+	    pIter = pIter->tail ();
+	  }
+	}
+	sel_ctx = sel_lst;
+
+	selector_stack.push_back (sel_ctx);
+	selector_stack.pop_back ();
+	in_at_root = old_in_at_root;
+	old_in_at_root = false;
+	env->current_frame ()[var] = sel_ctx;
+      }
+      else {
+	    env->current_frame()[var] = a->value()->perform(eval->with(env, backtrace));
+      }
     }
     return 0;
   }
diff --git a/parser.cpp b/parser.cpp
index c03abc8048..de133130ce 100644
--- a/parser.cpp
+++ b/parser.cpp
@@ -1219,6 +1219,10 @@ namespace Sass {
     if (lex< sequence< exactly<'%'>, optional< percentage > > >())
     { return new (ctx.mem) String_Constant(pstate, lexed); }
 
+    if (lex< ampersand >())
+    {
+      return new (ctx.mem) Selector_Reference(pstate);
+    }
     error("error reading values after " + lexed.to_string(), pstate);
 
     // unreachable statement
diff --git a/prelexer.cpp b/prelexer.cpp
index d63180e256..f385912dd6 100644
--- a/prelexer.cpp
+++ b/prelexer.cpp
@@ -404,6 +404,9 @@ namespace Sass {
     const char* percentage(const char* src) {
       return sequence< number, exactly<'%'> >(src);
     }
+    const char* ampersand(const char* src) {
+      return exactly<'&'>(src);
+    }
 
     const char* em(const char* src) {
       return sequence< number, exactly<em_kwd> >(src);
diff --git a/prelexer.hpp b/prelexer.hpp
index 3c08003ae6..3351bf8348 100644
--- a/prelexer.hpp
+++ b/prelexer.hpp
@@ -408,6 +408,7 @@ namespace Sass {
     const char* coefficient(const char* src);
     const char* binomial(const char* src);
     const char* percentage(const char* src);
+    const char* ampersand(const char* src);
     const char* dimension(const char* src);
     const char* hex(const char* src);
     const char* hexa(const char* src);