Implement fromEnvironment on bool, int and String

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 INCLUDE_DART_API_H_
 #define INCLUDE_DART_API_H_
 
 /** \mainpage Dart Embedding API Reference
@@ skipping 1459 matching lines @@
  *
  * \return A valid handle if no error occurs during the operation.
  */
 DART_EXPORT Dart_Handle Dart_StringToUTF8(Dart_Handle str,
                                           uint8_t** utf8_array,
                                           intptr_t* length);
 
 /**
  * Gets the data corresponding to the string object. This function returns
  * the data only for Latin-1 (ISO-8859-1) string objects. For all other
- * string objects it return and error.
+ * string objects it returns an error.
  *
  * \param str A string.
  * \param latin1_array An array allocated by the caller, used to return
  *   the string data.
  * \param length Used to pass in the length of the provided array.
  *   Used to return the length of the array which was actually used.
  *
  * \return A valid handle if no error occurs during the operation.
  */
 DART_EXPORT Dart_Handle Dart_StringToLatin1(Dart_Handle str,
@@ skipping 608 matching lines @@
  * name/arity to a Dart_NativeFunction. If no function is found, the
  * callback should return NULL.
  *
  * See Dart_SetNativeResolver.
  */
 typedef Dart_NativeFunction (*Dart_NativeEntryResolver)(Dart_Handle name,
                                                         int num_of_arguments);
 /* TODO(turnidge): Consider renaming to NativeFunctionResolver or
  * NativeResolver. */
 
+/*
+ * ===========
+ * Environment
+ * ===========
+ */
+
+/**
+ * An environment lookup callback function.
+ *
+ * \param name The name of the value to lookup in the environment.
+ *
+ * \return A valid handle to a string if the name exists in the
+ * current environment or Dart_Null() if not.
+ */
+typedef Dart_Handle (*Dart_EnvironmentCallback)(Dart_Handle name);
+
+/**
+ * Sets the environment callback for the current isolate. This
+ * callback is used to lookup environment values by name in the
+ * current environment. This enables the embedder to supply values for
+ * the const constructors bool.fromEnvironment, int.fromEnvironment
+ * and String.fromEnvironment.
+ */
+DART_EXPORT Dart_Handle Dart_SetEnvironmentCallback(
+    Dart_EnvironmentCallback callback);
+
 /**
  * Sets the callback used to resolve native functions for a library.
  *
  * \param library A library.
  * \param resolver A native entry resolver.
  *
  * \return A valid handle if the native resolver was set successfully.
  */
 DART_EXPORT Dart_Handle Dart_SetNativeResolver(
     Dart_Handle library,
@@ skipping 193 matching lines @@
  *
  * \param object An object.
  * \param peer A value to store in the peer field.
  *
  * \return Returns an error if 'object' is a subtype of Null, num, or
  *   bool.
  */
 DART_EXPORT Dart_Handle Dart_SetPeer(Dart_Handle object, void* peer);
 
 #endif  /* INCLUDE_DART_API_H_ */  /* NOLINT */