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pkg/dev_compiler/tool/input_sdk/lib/core/bool.dart

-// 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.
-
-part of dart.core;
-
-/**
- * The reserved words [:true:] and [:false:] denote objects that are the only
- * instances of this class.
- *
- * It is a compile-time error for a class to attempt to extend or implement
- * bool.
- */
-class bool {
-  /**
-   * Returns the boolean value of the environment declaration [name].
-   *
-   * The boolean value of the declaration is `true` if the declared value is
-   * the string `"true"`, and `false` if the value is `"false"`.
-   *
-   * In all other cases, including when there is no declaration for `name`,
-   * the result is the [defaultValue].
-   *
-   * The result is the same as would be returned by:
-   *
-   *     (const String.fromEnvironment(name) == "true")
-   *         ? true
-   *         : (const String.fromEnvironment(name) == "false")
-   *             ? false
-   *             : defaultValue
-   *
-   * Example:
-   *
-   *     const loggingFlag = const bool.fromEnvironment("logging");
-   *
-   * If you want to use a different truth-string than `"true"`, you can use the
-   * [String.fromEnvironment] constructor directly:
-   *
-   *     const isLoggingOn = (const String.fromEnvironment("logging") == "on");
-   */
-  external const factory bool.fromEnvironment(String name,
-                                              {bool defaultValue: false});
-
-  /**
-   * Returns [:"true":] if the receiver is [:true:], or [:"false":] if the
-   * receiver is [:false:].
-   */
-  String toString() {
-    return this ? "true" : "false";
-  }
-}