tests/test_ni_cast_extra.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # Copyright 2011 Alexis Laferrière <alexis.laf@xymus.net>
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License");
   6 # you may not use this file except in compliance with the License.
   7 # You may obtain a copy of the License at
   8 #
   9 #     http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 # See the License for the specific language governing permissions and
  15 # limitations under the License.
  16
  17 class A
  18     fun isa_b : Bool is extern import A as(B)
  19     fun as_b : nullable B is extern import A as(B), A as(nullable B)
  20 end
  21
  22 class B
  23 end
  24
  25 class C
  26 super A
  27     fun isa_a : Bool is extern import C as(A)
  28 end
  29
  30 class D # triangle
  31 super A
  32 super B
  33     init do end
  34     fun as_a : A is extern import D as(A)
  35 end
  36
  37 # isa
  38 var a = new A
  39 var c = new C
  40 var d = new D
  41
  42 print "a isa b {a.isa_b} (expected: false)"
  43 print "c isa a {c.isa_a} (expected: true)"
  44 print "d isa b {d.isa_b} (expected: true)"
  45
  46 var da = d.as_a
  47 var db = d.as_b
  48 var ab = a.as_b
  49
  50 print "da is null? {da==null} (expected: false)"
  51 print "db is null? {db==null} (expected: false)"
  52 print "ab is null? {ab==null} (expected: true)"