1. Dynamic compute the main closure that needs to be run by the main isolate

runtime/include/dart_api.h

 /*
  * Copyright (c) 2012, 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 RUNTIME_INCLUDE_DART_API_H_
 #define RUNTIME_INCLUDE_DART_API_H_
 
 /** \mainpage Dart Embedding API Reference
@@ skipping 1593 matching lines @@
 /**
  * Gets the value of a Double
  *
  * \param double_obj A Double
  * \param value Returns the value of the Double.
  *
  * \return A valid handle if no error occurs during the operation.
  */
 DART_EXPORT Dart_Handle Dart_DoubleValue(Dart_Handle double_obj, double* value);
 
+/**
+ * Returns a closure of top level function 'function_name' in the exported
+ * namespace of specified 'library'. If a top level function 'function_name'
+ * does not exist, looks for a top level getter 'function_name' and invokes
+ * it and returns the object returned by the getter.
+ *
+ * \param library Library object
+ * \param function_name Name of the top level function
+ *
+ * \return A valid Dart instance if no error occurs during the operation.
+ */
+DART_EXPORT Dart_Handle Dart_GetClosure(Dart_Handle library,
+                                        Dart_Handle function_name);
+
 
 /*
  * ========
  * Booleans
  * ========
  */
 
 /**
  * Returns the True object.
  *
@@ skipping 1754 matching lines @@
  */
 DART_EXPORT bool Dart_IsPrecompiledRuntime();
 
 
 /**
  *  Print a native stack trace. Used for crash handling.
  */
 DART_EXPORT void Dart_DumpNativeStackTrace(void* context);
 
 #endif /* INCLUDE_DART_API_H_ */ /* NOLINT */