src/metamodel/virtualtype.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # Copyright 2006-2008 Floréal Morandat <morandat@lirmm.fr>
   4 # Copyright 2008 Jean Privat <jean@pryen.org>
   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 # Virtual type (property of type type)
  19 package virtualtype
  20
  21 import type_formal
  22
  23 redef class MMGlobalProperty
  24         # Is self a virtual type
  25         meth is_virtual_type: Bool do return intro isa MMTypeProperty
  26 end
  27
  28 # Virtual type properties
  29 class MMTypeProperty
  30 special MMLocalProperty
  31         redef meth inherit_to(t)
  32         do
  33                 return new MMImplicitType(self, t)
  34         end
  35
  36         # Cached result of stype
  37         attr _stype_cache: MMVirtualType
  38
  39         # The virtual static type associated
  40         meth stype: MMVirtualType
  41         do
  42                 # If the signature is not build: Circular definition
  43                 if signature == null then return null
  44
  45                 var r = _stype_cache
  46                 if r == null then
  47                         r = new MMVirtualType(self)
  48                         _stype_cache = r
  49                 end
  50                 return r
  51         end
  52 end
  53
  54 redef class MMType
  55         # Select a virtual type property by its name
  56         meth select_virtual_type(name: Symbol): MMTypeProperty
  57         do
  58                 assert local_class != null
  59                 assert name != null
  60                 var res = select_property(local_class.virtual_type(name))
  61                 assert res isa MMTypeProperty
  62                 return res
  63         end
  64 end
  65
  66 class MMVirtualType
  67 special MMTypeFormal
  68         # The property associed
  69         readable attr _property: MMTypeProperty
  70
  71         protected init(p: MMTypeProperty)
  72         do
  73                 super(p.name, p.signature.return_type)
  74                 _property = p
  75         end
  76
  77         redef meth for_module(mod)
  78         do
  79                 var recv = _property.signature.recv.for_module(mod)
  80                 return adapt_to(recv)
  81         end
  82
  83         redef meth not_for_self
  84         do
  85                 return bound.not_for_self
  86         end
  87
  88         redef meth adapt_to(recv)
  89         do
  90                 # print "adapt {self} from {_property.signature.recv.module}::{_property.signature.recv} to {recv.module}::{recv}"
  91                 var prop = recv.select_property(_property.global)
  92                 assert prop isa MMTypeProperty
  93                 return prop.stype
  94         end
  95 end
  96
  97 redef class MMLocalClass
  98         meth virtual_type(s: Symbol): MMGlobalProperty
  99         do
 100                 var prop = get_property_by_name(s)
 101                 if prop.is_virtual_type then
 102                         return prop
 103                 end
 104                 return null
 105         end
 106 end
 107
 108 class MMImplicitType
 109 special MMTypeProperty
 110 special MMImplicitProperty
 111         init(p, t) do super
 112 end