src/metamodel/type_formal.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # Copyright 2004-2008 Jean Privat <jean@pryen.org>
   4 # Copyright 2006-2008 Floréal Morandat <morandat@lirmm.fr>
   5 #
   6 # Licensed under the Apache License, Version 2.0 (the "License");
   7 # you may not use this file except in compliance with the License.
   8 # You may obtain a copy of the License at
   9 #
  10 #     http://www.apache.org/licenses/LICENSE-2.0
  11 #
  12 # Unless required by applicable law or agreed to in writing, software
  13 # distributed under the License is distributed on an "AS IS" BASIS,
  14 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15 # See the License for the specific language governing permissions and
  16 # limitations under the License.
  17
  18 # Formal types
  19 package type_formal
  20
  21 import inheritance
  22
  23 redef class MMType
  24         # The type a indirect type refers to
  25         meth direct_type: MMType do return self
  26 end
  27
  28 # Formal types are named indirect types
  29 class MMTypeFormal
  30 special MMType
  31         redef meth is_valid do return _bound != null
  32
  33         # The name of the type
  34         readable attr _name: Symbol
  35
  36         # The type refered
  37         meth bound: MMType
  38         do
  39                 assert is_valid
  40                 return _bound
  41         end
  42         attr _bound: MMType
  43
  44         redef meth <(t) do return t != null and (t == self or t.is_supertype(_bound))
  45         redef meth is_supertype(t) do return _bound.is_supertype(t)
  46         redef meth is_nullable do return _bound.is_nullable
  47         redef meth direct_type do return _bound.direct_type
  48         redef meth local_class do return _bound.local_class
  49
  50         redef meth to_s do return _name.to_s
  51
  52         protected init(name: Symbol, bound: MMType)
  53         do
  54                 _name = name
  55                 _bound = bound
  56         end
  57 end
  58