Bam, mixins with arguments (including keyword args) are working properly.

context.hpp

@@ -12,6 +12,9 @@ namespace Sass {
     Environment(Environment* env) : frame(map<Token, Node>()), parent(env)
     { }
     
+    void link(Environment& env)
+    { parent = &env; }
+    
     bool query(const Token& key) const
     {
       if (frame.count(key)) return true;

document_eval_pending.cpp

@@ -42,13 +42,34 @@ namespace Sass {
         case Node::expansion: {
           Token name(n[0].token);
           Node args(n[1]);
-
           Node mixin(context.global_env[name]);
           Node params(mixin[1]);
           Node body(mixin[2].clone());
 
           n.children->pop_back();
           n.children->pop_back();
+
+          Environment m_env;
+          for (int i = 0, j = 0; i < args.size(); ++i) {
+            if (args[i].type == Node::assignment) {
+              Node arg(args[i]);
+              Token key(arg[0].token);
+              if (!m_env.query(key)) {
+                m_env[key] = eval(arg[1], context.global_env);
+              }
+            }
+            else {
+              // TO DO: ensure (j < params.size())
+              m_env[params[j].token] = eval(args[i], context.global_env);
+              ++j;
+            }
+          }
+          m_env.link(context.global_env);
+          
+          for (int i = 0; i < body.size(); ++i) {
+            body[i] = eval(body[i], m_env);
+          }
+          
           n += body;
         } break;
       }

evaluator.cpp

@@ -9,6 +9,19 @@ namespace Sass {
   {
     switch (expr.type)
     {
+      case Node::rule: {
+        Node rhs(expr[1]);
+        if (rhs.type == Node::comma_list || rhs.type == Node::space_list) {
+          for (int i = 0; i < rhs.size(); ++i) {
+            if (rhs[i].eval_me) rhs[i] = eval(rhs[i], env);
+          }
+        }
+        else {
+          expr[1] = eval(rhs, env);
+        }
+        return expr;
+      } break;
+
       case Node::comma_list:
       case Node::space_list: {
         if (expr.eval_me) {

spec/basic/17_basic_mixins/input.scss

+@mixin foo($x, $y) {
+  hugabug: $y $x;
+}
+
+@mixin bar($a, $b: flug) {
+  flugablug: $a $b glug;
+}
+
+@mixin hux() {
+  no: parameters here;
+}
+
+a {
+  hey: ho;
+  @include foo($x: kwd-arg another-kwd-arg, second, third);
+  @include foo(eks, why, $x: kwd-eks);
+  @include foo($y: kwd-y, $x: kwd-x);
+  goo: boo hoo;
+  @include hux;
+}
+
+
+$x: from a variable;
+
+div {
+  blah: blah $x blah;
+}
\ No newline at end of file

spec/basic/17_basic_mixins/output.css

+a {
+  hey: ho;
+  hugabug: third second;
+  hugabug: why eks;
+  hugabug: kwd-y kwd-x;
+  goo: boo hoo;
+  no: parameters here; }
+
+div {
+  blah: blah from a variable blah; }