Parsing back-references (i.e., the ampersand).

back_references.scss

+/*hey, ho {
+  & > boo, foo &.goo {
+    bloo: bloo;
+  }
+  blah: blah;
+}
+*/
+div {
+  a: a;
+  p {
+    b: b;
+    &* {
+      c: c;
+    }
+  }
+}
\ No newline at end of file

document_parser.cpp

@@ -53,25 +53,59 @@ namespace Sass {
         lex< exactly<'>'> >()) {
       selector << Node(line_number, Node::selector_combinator, lexed);
     }
-    selector << parse_simple_selector_sequence();
+    Node s(parse_simple_selector_sequence());
+    if (s.has_backref) selector.has_backref = true;
+    selector << s;
+    // if (s.terminal_backref) return selector;
     while (lex< exactly<'+'> >() ||
            lex< exactly<'~'> >() ||
            lex< exactly<'>'> >() ||
-           lex< ancestor_of >()) {
+           lex< ancestor_of >() ||
+           s.terminal_backref && lex< no_spaces >()) {
       selector << Node(line_number, Node::selector_combinator, lexed);
-      selector << parse_simple_selector_sequence();
+      s = parse_simple_selector_sequence();
+      if (s.has_backref) selector.has_backref = true;
+      selector << s;
+      // if (s.terminal_backref) break;
     }
+    
+    // while (1) {
+    //   if (lex< exactly<'+'> >() || lex< exactly<'~'> >() ||
+    //       lex< exactly<'>'> >() || lex< ancestor_of >()) {
+    //     selector << Node(line_number, Node::selector_combinator, lexed);
+    //     Node s(parse_simple_selector_sequence());
+    //     if (s.has_backref) selector.has_backref = true;
+    //     selector << s;
+    //   }
+    //   else if (selector.children->back().has_backref &&
+    //            selector.children->back().children->size() == 1 &&
+    //            lex< alternatives < type_selector, universal > >()) {
+    //     Node s(parse_simple_selector_sequence());
+    //     if (s.has_backref) selector.has_backref = true;
+    //     selector << s;
+    //   }
+    //   else break;
+    // }
     return selector;
   }
 
   Node Document::parse_simple_selector_sequence()
   {
-    Node sequence(line_number, Node::simple_selector_sequence, 1);
+    Node seq(line_number, Node::simple_selector_sequence, 1);
     if (lex< alternatives < type_selector, universal > >()) {
-      sequence << Node(line_number, Node::simple_selector, lexed);
+      seq << Node(line_number, Node::simple_selector, lexed);
+    }
+    else if (lex< exactly<'&'> >()) {
+      seq << Node(line_number, Node::backref, lexed);
+      seq.has_backref = true;
+      if (peek< sequence< no_spaces, alternatives< type_selector, universal > > >(position)) {
+        cerr << "Terminal backref!" << endl;
+        seq.terminal_backref = true;
+        return seq;
+      }
     }
     else {
-      sequence << parse_simple_selector();
+      seq << parse_simple_selector();
     }
     while (!peek< spaces >(position) &&
            !(peek < exactly<'+'> >(position) ||
@@ -79,9 +113,9 @@ namespace Sass {
              peek < exactly<'>'> >(position) ||
              peek < exactly<','> >(position) ||
              peek < exactly<'{'> >(position))) {
-      sequence << parse_simple_selector();
+      seq << parse_simple_selector();
     }
-    return sequence; 
+    return seq; 
   }
   
   Node Document::parse_simple_selector()

node.hpp

@@ -17,6 +17,7 @@ namespace Sass {
       selector,
       selector_combinator,
       simple_selector_sequence,
+      backref,
       simple_selector,
       type_selector,
       class_selector,
@@ -41,6 +42,8 @@ namespace Sass {
     bool has_rules_or_comments;
     bool has_rulesets;
     bool has_propsets;
+    bool has_backref;
+    bool terminal_backref;
     
     Node() : type(nil), children(0) { ++fresh; }
   
@@ -51,7 +54,9 @@ namespace Sass {
       type(n.type),
       has_rules_or_comments(n.has_rules_or_comments),
       has_rulesets(n.has_rulesets),
-      has_propsets(n.has_propsets)
+      has_propsets(n.has_propsets),
+      has_backref(n.has_backref),
+      terminal_backref(n.terminal_backref)
     { /*n.release();*/ ++copied; } // No joint custody.
   
     Node(size_t line_number, Type type, size_t length = 0)
@@ -61,7 +66,9 @@ namespace Sass {
       type(type),
       has_rules_or_comments(false),
       has_rulesets(false),
-      has_propsets(false)
+      has_propsets(false),
+      has_backref(false),
+      terminal_backref(false)
     { children->reserve(length); ++fresh; }
     
     Node(size_t line_number, Type type, const Node& n)
@@ -71,7 +78,9 @@ namespace Sass {
       type(type),
       has_rules_or_comments(false),
       has_rulesets(false),
-      has_propsets(false)
+      has_propsets(false),
+      has_backref(false),
+      terminal_backref(false)
     { ++fresh; }
     
     Node(size_t line_number, Type type, const Node& n, const Node& m)
@@ -81,7 +90,9 @@ namespace Sass {
       type(type),
       has_rules_or_comments(false),
       has_rulesets(false),
-      has_propsets(false)
+      has_propsets(false),
+      has_backref(false),
+      terminal_backref(false)
     {
       children->reserve(2);
       children->push_back(n);
@@ -96,7 +107,9 @@ namespace Sass {
       type(type),
       has_rules_or_comments(false),
       has_rulesets(false),
-      has_propsets(false)
+      has_propsets(false),
+      has_backref(false),
+      terminal_backref(false)
     { ++fresh; }
     
     //~Node() { delete children; }
@@ -111,6 +124,8 @@ namespace Sass {
       has_rules_or_comments = n.has_rules_or_comments;
       has_rulesets = n.has_rulesets;
       has_propsets = n.has_propsets;
+      has_backref = n.has_backref;
+      terminal_backref = n.terminal_backref;
       ++copied;
       return *this;
     }