Implemented the @if directive.

eval_apply.cpp

@@ -94,7 +94,7 @@ namespace Sass {
       
       case Node::root: {
         for (size_t i = 0, S = expr.size(); i < S; ++i) {
-          eval(expr[i], prefix, env, f_env, new_Node, ctx);
+          expr[i] = eval(expr[i], prefix, env, f_env, new_Node, ctx);
         }
         return expr;
       } break;
@@ -103,7 +103,7 @@ namespace Sass {
         Environment new_frame;
         new_frame.link(env);
         for (size_t i = 0, S = expr.size(); i < S; ++i) {
-          eval(expr[i], prefix, new_frame, f_env, new_Node, ctx);
+          expr[i] = eval(expr[i], prefix, new_frame, f_env, new_Node, ctx);
         }
         return expr;
       } break;
@@ -297,7 +297,24 @@ namespace Sass {
       case Node::css_import: {
         expr[0] = eval(expr[0], prefix, env, f_env, new_Node, ctx);
         return expr;
-      } break;     
+      } break;
+
+      case Node::if_directive: {
+        for (size_t i = 0, S = expr.size(); i < S; i += 2) {
+          if (expr[i].type() != Node::block) {
+            // cerr << "EVALUATING PREDICATE " << (i/2+1) << endl;
+            Node predicate_val(eval(expr[i], prefix, env, f_env, new_Node, ctx));
+            if ((predicate_val.type() != Node::boolean) || predicate_val.boolean_value()) {
+              // cerr << "EVALUATING CONSEQUENT " << (i/2+1) << endl;
+              return eval(expr[i+1], prefix, env, f_env, new_Node, ctx);
+            }
+          }
+          else {
+            // cerr << "EVALUATING ALTERNATIVE" << endl;
+            return eval(expr[i], prefix, env, f_env, new_Node, ctx);
+          }
+        }
+      } break;
 
       default: {
         return expr;

node.cpp

@@ -2,6 +2,7 @@
 #include <algorithm>
 #include "node.hpp"
 #include "error.hpp"
+#include <iostream>
 
 namespace Sass {
   using namespace std;
@@ -15,7 +16,7 @@ namespace Sass {
     if (type() != block && type() != expansion && type() != root) return;
     // size can change during flattening, so we need to call size() on each pass
     for (size_t i = 0; i < size(); ++i) {
-      if (at(i).type() == expansion) {
+      if ((at(i).type() == expansion) || (at(i).type() == block)) {
         Node expn(at(i));
         if (expn.has_expansions()) expn.flatten();
         ip_->has_statements |= expn.has_statements();

node.hpp

@@ -3,6 +3,7 @@
 #include <cstring>
 #include <string>
 #include <vector>
+#include <iostream>
 
 namespace Sass {
   using namespace std;
@@ -146,6 +147,11 @@ namespace Sass {
       expansion,
       arguments,
 
+      if_directive,
+      for_directive,
+      each_directive,
+      while_directive,
+
       variable,
       assignment
     };
@@ -189,6 +195,8 @@ namespace Sass {
     Token  token() const;
     Token  unit() const;
 
+    bool is_null_ptr() const;
+
     void flatten();
     
     bool operator==(Node rhs) const;
@@ -273,6 +281,7 @@ namespace Sass {
         case Node::rule:
         case Node::propset:   has_statements = true; break;
         case Node::ruleset:   has_blocks     = true; break;
+        case Node::if_directive:
         case Node::expansion: has_expansions = true; break;
         case Node::backref:   has_backref    = true; break;
         default:                                     break;
@@ -369,4 +378,6 @@ namespace Sass {
   inline Token  Node::token() const         { return ip_->value.token; }
   inline Token  Node::unit() const          { return ip_->unit(); }
 
+  inline bool Node::is_null_ptr() const { return !ip_; }
+
 }