Support compile time constant conditional expressions

runtime/vm/ast.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/ast.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
 #include "vm/isolate.h"
 #include "vm/object_store.h"
 #include "vm/resolver.h"
@@ skipping 358 matching lines @@
     case Token::kNOT:
       return val->IsBool() ? val : NULL;
     case Token::kBIT_NOT:
       return val->IsInteger() ? val : NULL;
     default:
       return NULL;
   }
 }
 
 
+bool ConditionalExprNode::IsPotentiallyConst() const {
+  return this->condition()->IsPotentiallyConst() &&
+    this->true_expr()->IsPotentiallyConst() &&
+    this->false_expr()->IsPotentiallyConst();
+}
+
+
+const Instance* ConditionalExprNode::EvalConstExpr() const {
+  const Instance* cond = this->condition()->EvalConstExpr();
+  if ((cond != NULL) &&
+      (this->true_expr()->EvalConstExpr() != NULL) &&
+      (this->false_expr()->EvalConstExpr() != NULL)) {
+    return cond;
+  }
+  return NULL;
+}
+
+
 bool ClosureNode::IsPotentiallyConst() const {
   if (function().IsImplicitStaticClosureFunction()) {
     return true;
   }
   return false;
 }
 
 
 const Instance* ClosureNode::EvalConstExpr() const {
   if (function().IsImplicitStaticClosureFunction()) {
@@ skipping 164 matching lines @@
   if (result.IsError() || result.IsNull()) {
     // TODO(turnidge): We could get better error messages by returning
     // the Error object directly to the parser.  This will involve
     // replumbing all of the EvalConstExpr methods.
     return NULL;
   }
   return &Instance::ZoneHandle(Instance::Cast(result).raw());
 }
 
 }  // namespace dart