Add Dart_Null, Dart_True, and Dart_False.

runtime/include/dart_api.h

 // 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.
 
 #ifndef INCLUDE_DART_API_H_
 #define INCLUDE_DART_API_H_
 
 /** \mainpage Dart Embedding API Reference
  *
  * Dart is a class-based programming language for creating structured
@@ skipping 120 matching lines @@
 // TODO(turnidge): Accept printf-style args here.
 
 /**
  * Allocates a persistent handle for an object.
  *
  * This handle has the lifetime of the current isolate unless it is
  * explicitly deallocated by calling Dart_DeletePersistentHandle.
  *
  * Requires there to be a current isolate.
  */
 DART_EXPORT Dart_Handle Dart_NewPersistentHandle(Dart_Handle object);

[siva, 2011/11/03 21:45:25]

What is the use case for creating a new persistent handle from another
persistent handle?
Seems like clone functionality.

[turnidge, 2011/11/04 00:03:17]

Someone who is passed a Dart_Handle doesn't know whether it is persistent or
not.  Even if they know it is persistent, they don't know what lifetime it will
have.  My thought is that it makes sense to be able to take an arbitrary
Dart_Handle and be able to save it for later.  Does this make sense?

-// TODO(turnidge): This function currently only works when passes a
-// local handle.  Make it work for both local and persistent handles.
 
 /**
  * Deallocates a persistent handle.
  *
  * Requires there to be a current isolate.
  */
 DART_EXPORT void Dart_DeletePersistentHandle(Dart_Handle object);
 
 /**
  * Takes a persistent handle and makes it weak.
@@ skipping 279 matching lines @@
  *
  * The previous scope (if any) becomes the current scope.
  *
  * Requires there to be a current isolate.
  */
 DART_EXPORT void Dart_ExitScope();
 
 // --- Objects ----
 
 /**
+ * Returns the null object.
+ *
+ * Requires there to be a current isolate.
+ *
+ * \return A handle to the null object.
+ */
+DART_EXPORT Dart_Handle Dart_Null();
+
+/**
  * Is this object null?
  */
 DART_EXPORT bool Dart_IsNull(Dart_Handle object);
 
 /**
  * Converts an object to a string.
  *
  * If an exception occurs during the conversion, this is treated as an
  * error.
  *
@@ skipping 107 matching lines @@
  *   the next call to Dart_ExitScope.
  *
  * \return A valid handle if no error occurs during the operation.
  */
 DART_EXPORT Dart_Handle Dart_IntegerValueHexCString(Dart_Handle integer,
                                                     const char** value);
 
 // --- Booleans ----
 
 /**
+ * Returns the True object.
+ *
+ * Requires there to be a current isolate.
+ *
+ * \return A handle to the True object.
+ */
+DART_EXPORT Dart_Handle Dart_True();
+
+/**
+ * Returns the False object.
+ *
+ * Requires there to be a current isolate.
+ *
+ * \return A handle to the False object.
+ */
+DART_EXPORT Dart_Handle Dart_False();
+
+/**
  * Is this object a Boolean?
  */
 DART_EXPORT bool Dart_IsBoolean(Dart_Handle object);
 
 /**
  * Returns a Boolean with the provided value.
  *
  * \param value true or false.
  *
  * \return The Boolean object if no errors occurs. Otherwise returns
@@ skipping 537 matching lines @@
 
 // --- Profiling support ----
 
 // External pprof support for gathering and dumping symbolic
 // information that can be used for better profile reports for
 // dynamically generated code.
 DART_EXPORT void Dart_InitPprofSupport();
 DART_EXPORT void Dart_GetPprofSymbolInfo(void** buffer, int* buffer_size);
 
 #endif  // INCLUDE_DART_API_H_