src/metamodel/static_type.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 # Static types and property signatures
  19 package static_type
  20
  21 intrude import abstractmetamodel
  22
  23 redef class MMLocalClass
  24         # Cached result of get_type
  25         attr _base_type_cache: MMType
  26
  27         # Return the type of self for this class
  28         meth get_type: MMType
  29         do
  30                 if _base_type_cache == null then _base_type_cache = new MMTypeSimpleClass(self)
  31                 return _base_type_cache
  32         end
  33
  34         # Register a new ancestor
  35         protected meth add_ancestor(a: MMAncestor)
  36         do
  37                 assert not _ancestors.has_key(a.local_class)
  38                 assert a.local_class != self
  39                 _ancestors[a.local_class] = a
  40         end
  41
  42         # Array of ancestor that associate each superclass with the corresponding ancestor
  43         readable attr _ancestors: Map[MMLocalClass, MMAncestor]
  44
  45         # The ancestor type for a given superclass
  46         meth ancestor(c: MMLocalClass): MMType
  47         do
  48                 assert _ancestors != null
  49                 if _ancestors.has_key(c) then
  50                         return _ancestors[c].stype
  51                 end
  52                 return null
  53         end
  54 end
  55
  56 redef class MMLocalProperty
  57         # The signature of the property (where it is declared)
  58         readable writable attr _signature: MMSignature
  59
  60         attr _signatures_cache: HashMap[MMType, MMSignature] = new HashMap[MMType, MMSignature]
  61
  62         # Return the adapted signature of self for a receiver of type t
  63         meth signature_for(t: MMType): MMSignature do
  64                 if t == local_class.get_type then return signature
  65
  66                 if _signatures_cache.has_key(t) then return _signatures_cache[t]
  67
  68                 var res = signature.adaptation_to(t)
  69                 _signatures_cache[t] = res
  70                 return res
  71         end
  72 end
  73
  74 # Signature for local properties
  75 class MMSignature
  76         # The type of the reveiver
  77         readable attr _recv: MMType
  78
  79         # The parameter types
  80         attr _params: Array[MMType]
  81
  82         # The return type
  83         readable attr _return_type: MMType
  84
  85         # Number of parameters
  86         meth arity: Int
  87         do
  88                 assert _params != null
  89                 return _params.length
  90         end
  91
  92         # Is self a valid subtype of an other signature
  93         meth <(s: MMSignature): Bool
  94         do
  95                 assert s != null
  96                 if self == s then
  97                         return true
  98                 end
  99                 assert _recv.module == s.recv.module
 100                 assert arity == s.arity
 101                 assert (_return_type == null) == (s.return_type == null)
 102                 if _return_type != null and not _return_type < s.return_type then
 103                         return false
 104                 end
 105
 106                 for i in [0..arity[ do
 107                         if not s[i] < self[i] then
 108                                 return false
 109                         end
 110                 end
 111                 return true
 112         end
 113
 114         # The type of the i-th parameter
 115         meth [](i: Int): MMType
 116         do
 117                 assert _params.length > i
 118                 return _params[i]
 119         end
 120
 121         redef meth to_s
 122         do
 123                 var s: String
 124                 if _params != null and _params.length > 0 then
 125                         var tmp: String
 126                         var a = new Array[String].with_capacity(_params.length)
 127                         for i in [0.._params.length[ do
 128                                 #var pn = _params_name[i]
 129                                 var p = _params[i]
 130                                 #a.add("{pn}: {p}")
 131                                 a.add(p.to_s)
 132                         end
 133                         s = "({a.join(",")})"
 134                 else
 135                         s = ""
 136                 end
 137                 if _return_type != null then
 138                         s.append(": {_return_type}")
 139                 end
 140                 return s
 141         end
 142
 143         # Adapt the signature to a different receiver
 144         meth adaptation_to(r: MMType): MMSignature
 145         do
 146                 if _recv == r then
 147                         return self
 148                 end
 149                 var mod = r.module
 150                 var p = _params
 151                 if p != null then
 152                         p = new Array[MMType]
 153                         for i in _params do
 154                                 p.add(i.for_module(mod).adapt_to(r))
 155                         end
 156                 end
 157                 var rv = _return_type
 158                 if rv != null then
 159                         rv = rv.for_module(mod).adapt_to(r)
 160                 end
 161                 return new MMSignature(p,rv,r)
 162         end
 163
 164         init(params: Array[MMType], return_type: MMType, r: MMType)
 165         do
 166                 assert params != null
 167                 _params = params
 168                 _return_type = return_type
 169                 _recv = r
 170         end
 171 end
 172
 173 # Inheritance relation between two types
 174 abstract class MMAncestor
 175         # The inherited type
 176         readable writable attr _stype: MMType
 177
 178         # The inheriter (heir) type
 179         readable writable attr _inheriter: MMType
 180
 181         meth is_reffinement: Bool do
 182                 return stype.module != stype.module
 183         end
 184
 185         meth is_specialisation: Bool do
 186                 return stype.local_class.global != inheriter.local_class.global
 187         end
 188
 189         # The inherited class
 190         meth local_class: MMLocalClass is abstract
 191
 192         redef meth to_s
 193         do
 194                 if stype == null then
 195                         return local_class.to_s
 196                 else
 197                         return stype.to_s
 198                 end
 199         end
 200 end
 201
 202 # A static type
 203 # Note that static type a related to a specific module
 204 abstract class MMType
 205         # The module where self makes sence
 206         meth module: MMModule is abstract
 207
 208         # The local class that self direclty or indirectly refers to
 209         meth local_class: MMLocalClass is abstract
 210
 211         # Is self a valid subtype of t
 212         meth <(t : MMType): Bool is abstract
 213
 214         # Is self a valid supertype of t
 215         # This method must be only called within definition of < if
 216         # a double dispatch is needed
 217         meth is_supertype(t: MMType): Bool is abstract
 218
 219         # Select a method from its name
 220         meth select_method(name: Symbol): MMMethod
 221         do
 222                 assert local_class != null
 223                 assert name != null
 224                 var res = select_property(local_class.method(name))
 225                 assert res isa MMMethod
 226                 return res
 227         end
 228
 229         # Select an attribute from its name
 230         meth select_attribute(name: Symbol): MMAttribute
 231         do
 232                 assert name != null
 233                 assert local_class != null
 234                 var res = select_property(local_class.attribute(name))
 235                 assert res isa MMAttribute
 236                 return res
 237         end
 238
 239         # Select a local property from its global property
 240         meth select_property(t: MMGlobalProperty): MMLocalProperty is abstract
 241
 242         # Adapt self to another module
 243         meth for_module(mod: MMModule): MMType is abstract
 244
 245         # Get the type adapted to another receiver type
 246         # Useful for formal types
 247         meth adapt_to(recv: MMType): MMType is abstract
 248
 249         # Adapt self to another local class context
 250         # Useful for genericity
 251         meth upcast_for(c: MMLocalClass): MMType is abstract
 252
 253         # Return a type approximation if the reveiver is not self
 254         # Useful for virtual types
 255         meth not_for_self: MMType do return self
 256 end
 257
 258 class MMTypeClass
 259 special MMType
 260         redef readable attr _local_class: MMLocalClass
 261         redef meth module do return _local_class.module end
 262         redef meth <(t) do return t != null and t.is_supertype(self)
 263
 264         redef meth to_s
 265         do
 266                 return _local_class.to_s
 267         end
 268
 269         redef meth upcast_for(c)
 270         do
 271                 assert _local_class != null
 272                 assert c != null
 273
 274                 var t: MMType = self
 275                 if _local_class != c then
 276                         t = _local_class.ancestor(c)
 277                 end
 278                 assert t != null
 279                 return t
 280         end
 281
 282         init(c : MMLocalClass)
 283         do
 284                 _local_class = c
 285         end
 286 end
 287
 288 class MMTypeSimpleClass
 289 special MMTypeClass
 290         redef meth is_supertype(t)
 291         do
 292                 return  t.local_class.cshe <= _local_class
 293         end
 294
 295         redef meth select_property(g)
 296         do
 297                 assert _local_class != null
 298                 if g == null then
 299                         return null
 300                 end
 301                 return _local_class[g]
 302         end
 303
 304         redef meth for_module(mod)
 305         do
 306                 var t: MMType = self
 307                 if module != mod then
 308                         t = _local_class.for_module(mod).get_type
 309                 end
 310                 assert t != null
 311                 return t
 312         end
 313
 314         redef meth adapt_to(recv) do return self
 315
 316         redef init(c: MMLocalClass)
 317         do
 318                 super(c)
 319         end
 320 end
 321
 322 # The type of null
 323 class MMTypeNone
 324 special MMType
 325         redef readable attr _module: MMModule
 326         redef meth <(t) do return true
 327         redef meth is_supertype(t) do return false
 328         redef meth local_class do abort
 329         redef meth upcast_for(c) do return self
 330
 331         private init(m: MMModule) do _module = m
 332 end
 333
 334 redef class MMModule
 335         # The type of null
 336         readable attr _type_none: MMTypeNone = new MMTypeNone(self)
 337 end