Language/05_Variables/1_Evaluation_of_Implicit_Variable_Getters_A01_t01.dart

/*
 * 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.
 */
/**
 * @assertion Let d be the declaration of a variable v.  If d is a local or
 * instance variable, then the invocation of the implicit getter of v
 * evaluates to the value stored in v.
 * If d is a static or library variable then the implicit getter method of v
 * executes as follows:
 * Non-constant variable declaration with initializer. If d is of one of the
 * forms var v = e; , T v = e; , final v = e; , final T v = e; , static v = e;
 * ,static T v = e; , static final v = e;  or static final T v = e; and no
 * value has yet been stored into v then the initializer expression e is
 * evaluated. If, during the evaluation of e, the getter for v is invoked,
 * a CyclicInitializationError is thrown. If the evaluation succeeded yielding
 * an object o, let r = o, otherwise let r = null. In any case, r is stored
 * into v. The result of executing the getter is r.
 * Constant variable declaration. If d is of one of the forms const v = e; ,
 * const T v = e; , static const v = e;  or static const T v = e; the result
 * of the getter is the value of the compile time constant e. Note that a
 * compile time constant cannot depend on itself, so no cyclic references can
 * occur. Otherwise
 * Variable declaration without initializer. The result of executing the
 * getter method is the value stored in v.
 * @description Checks the result of the getter and that the initializer
 * expression  is evaluated only once.
 * @author msyabro
 * @reviewer iefremov
 */
import "../../Utils/expect.dart";

String log = "";

writeLog(int i) {
  log = "${log}${i}";
  return i;
}

class C {
  static var a = writeLog(1);
  static int b = writeLog(2);
  static final c = writeLog(3);
  static final int d = writeLog(4);
}

main() {
  Expect.equals(4, C.d);
  Expect.equals(1, C.a);
  Expect.equals(2, C.b);
  Expect.equals(3, C.c);

  Expect.equals("4123", log, "Lazy static getters execution was wrong!");
}