1 # This file is part of NIT ( http://www.nitlanguage.org ).
3 # Copyright 2012 Jean Privat <jean@pryen.org>
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
9 # http://www.apache.org/licenses/LICENSE-2.0
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.
17 # Classes, types and properties
19 # All three concepts are defined in this same module because these are strongly connected:
20 # * types are based on classes
21 # * classes contains properties
22 # * some properties are types (virtual types)
24 # TODO: liearization, extern stuff
25 # FIXME: better handling of the types
31 private import more_collections
35 var mclasses
= new Array[MClass]
37 # All known properties
38 var mproperties
= new Array[MProperty]
40 # Hierarchy of class definition.
42 # Each classdef is associated with its super-classdefs in regard to
43 # its module of definition.
44 var mclassdef_hierarchy
= new POSet[MClassDef]
46 # Class-type hierarchy restricted to the introduction.
48 # The idea is that what is true on introduction is always true whatever
49 # the module considered.
50 # Therefore, this hierarchy is used for a fast positive subtype check.
52 # This poset will evolve in a monotonous way:
53 # * Two non connected nodes will remain unconnected
54 # * New nodes can appear with new edges
55 private var intro_mtype_specialization_hierarchy
= new POSet[MClassType]
57 # Global overlapped class-type hierarchy.
58 # The hierarchy when all modules are combined.
59 # Therefore, this hierarchy is used for a fast negative subtype check.
61 # This poset will evolve in an anarchic way. Loops can even be created.
63 # FIXME decide what to do on loops
64 private var full_mtype_specialization_hierarchy
= new POSet[MClassType]
66 # Collections of classes grouped by their short name
67 private var mclasses_by_name
= new MultiHashMap[String, MClass]
69 # Return all class named `name`.
71 # If such a class does not exist, null is returned
72 # (instead of an empty array)
74 # Visibility or modules are not considered
75 fun get_mclasses_by_name
(name
: String): nullable Array[MClass]
77 return mclasses_by_name
.get_or_null
(name
)
80 # Collections of properties grouped by their short name
81 private var mproperties_by_name
= new MultiHashMap[String, MProperty]
83 # Return all properties named `name`.
85 # If such a property does not exist, null is returned
86 # (instead of an empty array)
88 # Visibility or modules are not considered
89 fun get_mproperties_by_name
(name
: String): nullable Array[MProperty]
91 return mproperties_by_name
.get_or_null
(name
)
95 var null_type
= new MNullType(self)
97 # Build an ordered tree with from `concerns`
98 fun concerns_tree
(mconcerns
: Collection[MConcern]): ConcernsTree do
99 var seen
= new HashSet[MConcern]
100 var res
= new ConcernsTree
102 var todo
= new Array[MConcern]
103 todo
.add_all mconcerns
105 while not todo
.is_empty
do
107 if seen
.has
(c
) then continue
108 var pc
= c
.parent_concern
122 # An OrderedTree that can be easily refined for display purposes
124 super OrderedTree[MConcern]
128 # All the classes introduced in the module
129 var intro_mclasses
= new Array[MClass]
131 # All the class definitions of the module
132 # (introduction and refinement)
133 var mclassdefs
= new Array[MClassDef]
135 # Does the current module has a given class `mclass`?
136 # Return true if the mmodule introduces, refines or imports a class.
137 # Visibility is not considered.
138 fun has_mclass
(mclass
: MClass): Bool
140 return self.in_importation
<= mclass
.intro_mmodule
143 # Full hierarchy of introduced ans imported classes.
145 # Create a new hierarchy got by flattening the classes for the module
146 # and its imported modules.
147 # Visibility is not considered.
149 # Note: this function is expensive and is usually used for the main
150 # module of a program only. Do not use it to do you own subtype
152 fun flatten_mclass_hierarchy
: POSet[MClass]
154 var res
= self.flatten_mclass_hierarchy_cache
155 if res
!= null then return res
156 res
= new POSet[MClass]
157 for m
in self.in_importation
.greaters
do
158 for cd
in m
.mclassdefs
do
161 for s
in cd
.supertypes
do
162 res
.add_edge
(c
, s
.mclass
)
166 self.flatten_mclass_hierarchy_cache
= res
170 # Sort a given array of classes using the linearization order of the module
171 # The most general is first, the most specific is last
172 fun linearize_mclasses
(mclasses
: Array[MClass])
174 self.flatten_mclass_hierarchy
.sort
(mclasses
)
177 # Sort a given array of class definitions using the linearization order of the module
178 # the refinement link is stronger than the specialisation link
179 # The most general is first, the most specific is last
180 fun linearize_mclassdefs
(mclassdefs
: Array[MClassDef])
182 var sorter
= new MClassDefSorter(self)
183 sorter
.sort
(mclassdefs
)
186 # Sort a given array of property definitions using the linearization order of the module
187 # the refinement link is stronger than the specialisation link
188 # The most general is first, the most specific is last
189 fun linearize_mpropdefs
(mpropdefs
: Array[MPropDef])
191 var sorter
= new MPropDefSorter(self)
192 sorter
.sort
(mpropdefs
)
195 private var flatten_mclass_hierarchy_cache
: nullable POSet[MClass] = null
197 # The primitive type `Object`, the root of the class hierarchy
198 var object_type
: MClassType = self.get_primitive_class
("Object").mclass_type
is lazy
200 # The type `Pointer`, super class to all extern classes
201 var pointer_type
: MClassType = self.get_primitive_class
("Pointer").mclass_type
is lazy
203 # The primitive type `Bool`
204 var bool_type
: MClassType = self.get_primitive_class
("Bool").mclass_type
is lazy
206 # The primitive type `Int`
207 var int_type
: MClassType = self.get_primitive_class
("Int").mclass_type
is lazy
209 # The primitive type `Char`
210 var char_type
: MClassType = self.get_primitive_class
("Char").mclass_type
is lazy
212 # The primitive type `Float`
213 var float_type
: MClassType = self.get_primitive_class
("Float").mclass_type
is lazy
215 # The primitive type `String`
216 var string_type
: MClassType = self.get_primitive_class
("String").mclass_type
is lazy
218 # The primitive type `NativeString`
219 var native_string_type
: MClassType = self.get_primitive_class
("NativeString").mclass_type
is lazy
221 # A primitive type of `Array`
222 fun array_type
(elt_type
: MType): MClassType do return array_class
.get_mtype
([elt_type
])
224 # The primitive class `Array`
225 var array_class
: MClass = self.get_primitive_class
("Array") is lazy
227 # A primitive type of `NativeArray`
228 fun native_array_type
(elt_type
: MType): MClassType do return native_array_class
.get_mtype
([elt_type
])
230 # The primitive class `NativeArray`
231 var native_array_class
: MClass = self.get_primitive_class
("NativeArray") is lazy
233 # The primitive type `Sys`, the main type of the program, if any
234 fun sys_type
: nullable MClassType
236 var clas
= self.model
.get_mclasses_by_name
("Sys")
237 if clas
== null then return null
238 return get_primitive_class
("Sys").mclass_type
241 # The primitive type `Finalizable`
242 # Used to tag classes that need to be finalized.
243 fun finalizable_type
: nullable MClassType
245 var clas
= self.model
.get_mclasses_by_name
("Finalizable")
246 if clas
== null then return null
247 return get_primitive_class
("Finalizable").mclass_type
250 # Force to get the primitive class named `name` or abort
251 fun get_primitive_class
(name
: String): MClass
253 var cla
= self.model
.get_mclasses_by_name
(name
)
254 # Filter classes by introducing module
255 if cla
!= null then cla
= [for c
in cla
do if self.in_importation
<= c
.intro_mmodule
then c
]
256 if cla
== null or cla
.is_empty
then
257 if name
== "Bool" and self.model
.get_mclasses_by_name
("Object") != null then
258 # Bool is injected because it is needed by engine to code the result
259 # of the implicit casts.
260 var c
= new MClass(self, name
, null, enum_kind
, public_visibility
)
261 var cladef
= new MClassDef(self, c
.mclass_type
, new Location(null, 0,0,0,0))
262 cladef
.set_supertypes
([object_type
])
263 cladef
.add_in_hierarchy
266 print
("Fatal Error: no primitive class {name} in {self}")
269 if cla
.length
!= 1 then
270 var msg
= "Fatal Error: more than one primitive class {name} in {self}:"
271 for c
in cla
do msg
+= " {c.full_name}"
278 # Try to get the primitive method named `name` on the type `recv`
279 fun try_get_primitive_method
(name
: String, recv
: MClass): nullable MMethod
281 var props
= self.model
.get_mproperties_by_name
(name
)
282 if props
== null then return null
283 var res
: nullable MMethod = null
284 for mprop
in props
do
285 assert mprop
isa MMethod
286 var intro
= mprop
.intro_mclassdef
287 for mclassdef
in recv
.mclassdefs
do
288 if not self.in_importation
.greaters
.has
(mclassdef
.mmodule
) then continue
289 if not mclassdef
.in_hierarchy
.greaters
.has
(intro
) then continue
292 else if res
!= mprop
then
293 print
("Fatal Error: ambigous property name '{name}'; conflict between {mprop.full_name} and {res.full_name}")
302 private class MClassDefSorter
304 redef type COMPARED: MClassDef
306 redef fun compare
(a
, b
)
310 if ca
!= cb
then return mmodule
.flatten_mclass_hierarchy
.compare
(ca
, cb
)
311 return mmodule
.model
.mclassdef_hierarchy
.compare
(a
, b
)
315 private class MPropDefSorter
317 redef type COMPARED: MPropDef
319 redef fun compare
(pa
, pb
)
325 if ca
!= cb
then return mmodule
.flatten_mclass_hierarchy
.compare
(ca
, cb
)
326 return mmodule
.model
.mclassdef_hierarchy
.compare
(a
, b
)
332 # `MClass` are global to the model; it means that a `MClass` is not bound to a
333 # specific `MModule`.
335 # This characteristic helps the reasoning about classes in a program since a
336 # single `MClass` object always denote the same class.
338 # The drawback is that classes (`MClass`) contain almost nothing by themselves.
339 # These do not really have properties nor belong to a hierarchy since the property and the
340 # hierarchy of a class depends of the refinement in the modules.
342 # Most services on classes require the precision of a module, and no one can asks what are
343 # the super-classes of a class nor what are properties of a class without precising what is
344 # the module considered.
346 # For instance, during the typing of a source-file, the module considered is the module of the file.
347 # eg. the question *is the method `foo` exists in the class `Bar`?* must be reformulated into
348 # *is the method `foo` exists in the class `Bar` in the current module?*
350 # During some global analysis, the module considered may be the main module of the program.
354 # The module that introduce the class
355 # While classes are not bound to a specific module,
356 # the introducing module is used for naming an visibility
357 var intro_mmodule
: MModule
359 # The short name of the class
360 # In Nit, the name of a class cannot evolve in refinements
361 redef var name
: String
363 # The canonical name of the class
365 # It is the name of the class prefixed by the full_name of the `intro_mmodule`
366 # Example: `"owner::module::MyClass"`
367 redef var full_name
is lazy
do
368 return "{self.intro_mmodule.namespace_for(visibility)}::{name}"
371 redef var c_name
is lazy
do
372 return "{intro_mmodule.c_namespace_for(visibility)}__{name.to_cmangle}"
375 # The number of generic formal parameters
376 # 0 if the class is not generic
377 var arity
: Int is noinit
379 # Each generic formal parameters in order.
380 # is empty if the class is not generic
381 var mparameters
= new Array[MParameterType]
383 # A string version of the signature a generic class.
385 # eg. `Map[K: nullable Object, V: nullable Object]`
387 # If the class in non generic the name is just given.
390 fun signature_to_s
: String
392 if arity
== 0 then return name
393 var res
= new FlatBuffer
396 for i
in [0..arity
[ do
397 if i
> 0 then res
.append
", "
398 res
.append mparameters
[i
].name
400 res
.append intro
.bound_mtype
.arguments
[i
].to_s
406 # Initialize `mparameters` from their names.
407 protected fun setup_parameter_names
(parameter_names
: nullable Array[String]) is
410 if parameter_names
== null then
413 self.arity
= parameter_names
.length
416 # Create the formal parameter types
418 assert parameter_names
!= null
419 var mparametertypes
= new Array[MParameterType]
420 for i
in [0..arity
[ do
421 var mparametertype
= new MParameterType(self, i
, parameter_names
[i
])
422 mparametertypes
.add
(mparametertype
)
424 self.mparameters
= mparametertypes
425 var mclass_type
= new MGenericType(self, mparametertypes
)
426 self.mclass_type
= mclass_type
427 self.get_mtype_cache
[mparametertypes
] = mclass_type
429 self.mclass_type
= new MClassType(self)
433 # The kind of the class (interface, abstract class, etc.)
434 # In Nit, the kind of a class cannot evolve in refinements
437 # The visibility of the class
438 # In Nit, the visibility of a class cannot evolve in refinements
439 var visibility
: MVisibility
443 intro_mmodule
.intro_mclasses
.add
(self)
444 var model
= intro_mmodule
.model
445 model
.mclasses_by_name
.add_one
(name
, self)
446 model
.mclasses
.add
(self)
449 redef fun model
do return intro_mmodule
.model
451 # All class definitions (introduction and refinements)
452 var mclassdefs
= new Array[MClassDef]
455 redef fun to_s
do return self.name
457 # The definition that introduces the class.
459 # Warning: such a definition may not exist in the early life of the object.
460 # In this case, the method will abort.
462 # Use `try_intro` instead
463 var intro
: MClassDef is noinit
465 # The definition that introduces the class or null if not yet known.
468 fun try_intro
: nullable MClassDef do
469 if isset _intro
then return _intro
else return null
472 # Return the class `self` in the class hierarchy of the module `mmodule`.
474 # SEE: `MModule::flatten_mclass_hierarchy`
475 # REQUIRE: `mmodule.has_mclass(self)`
476 fun in_hierarchy
(mmodule
: MModule): POSetElement[MClass]
478 return mmodule
.flatten_mclass_hierarchy
[self]
481 # The principal static type of the class.
483 # For non-generic class, mclass_type is the only `MClassType` based
486 # For a generic class, the arguments are the formal parameters.
487 # i.e.: for the class Array[E:Object], the `mclass_type` is Array[E].
488 # If you want Array[Object] the see `MClassDef::bound_mtype`
490 # For generic classes, the mclass_type is also the way to get a formal
491 # generic parameter type.
493 # To get other types based on a generic class, see `get_mtype`.
495 # ENSURE: `mclass_type.mclass == self`
496 var mclass_type
: MClassType is noinit
498 # Return a generic type based on the class
499 # Is the class is not generic, then the result is `mclass_type`
501 # REQUIRE: `mtype_arguments.length == self.arity`
502 fun get_mtype
(mtype_arguments
: Array[MType]): MClassType
504 assert mtype_arguments
.length
== self.arity
505 if self.arity
== 0 then return self.mclass_type
506 var res
= get_mtype_cache
.get_or_null
(mtype_arguments
)
507 if res
!= null then return res
508 res
= new MGenericType(self, mtype_arguments
)
509 self.get_mtype_cache
[mtype_arguments
.to_a
] = res
513 private var get_mtype_cache
= new HashMap[Array[MType], MGenericType]
515 # Is there a `new` factory to allow the pseudo instantiation?
516 var has_new_factory
= false is writable
518 # Is `self` a standard or abstract class kind?
519 var is_class
: Bool is lazy
do return kind
== concrete_kind
or kind
== abstract_kind
521 # Is `self` an interface kind?
522 var is_interface
: Bool is lazy
do return kind
== interface_kind
524 # Is `self` an enum kind?
525 var is_enum
: Bool is lazy
do return kind
== enum_kind
527 # Is `self` and abstract class?
528 var is_abstract
: Bool is lazy
do return kind
== abstract_kind
532 # A definition (an introduction or a refinement) of a class in a module
534 # A `MClassDef` is associated with an explicit (or almost) definition of a
535 # class. Unlike `MClass`, a `MClassDef` is a local definition that belong to
536 # a specific class and a specific module, and contains declarations like super-classes
539 # It is the class definitions that are the backbone of most things in the model:
540 # ClassDefs are defined with regard with other classdefs.
541 # Refinement and specialization are combined to produce a big poset called the `Model::mclassdef_hierarchy`.
543 # Moreover, the extension and the intention of types is defined by looking at the MClassDefs.
547 # The module where the definition is
550 # The associated `MClass`
551 var mclass
: MClass is noinit
553 # The bounded type associated to the mclassdef
555 # For a non-generic class, `bound_mtype` and `mclass.mclass_type`
559 # For the classdef Array[E: Object], the bound_mtype is Array[Object].
560 # If you want Array[E], then see `mclass.mclass_type`
562 # ENSURE: `bound_mtype.mclass == self.mclass`
563 var bound_mtype
: MClassType
565 # The origin of the definition
566 var location
: Location
568 # Internal name combining the module and the class
569 # Example: "mymodule#MyClass"
570 redef var to_s
: String is noinit
574 self.mclass
= bound_mtype
.mclass
575 mmodule
.mclassdefs
.add
(self)
576 mclass
.mclassdefs
.add
(self)
577 if mclass
.intro_mmodule
== mmodule
then
578 assert not isset mclass
._intro
581 self.to_s
= "{mmodule}#{mclass}"
584 # Actually the name of the `mclass`
585 redef fun name
do return mclass
.name
587 # The module and class name separated by a '#'.
589 # The short-name of the class is used for introduction.
590 # Example: "my_module#MyClass"
592 # The full-name of the class is used for refinement.
593 # Example: "my_module#intro_module::MyClass"
594 redef var full_name
is lazy
do
597 # private gives 'p::m#A'
598 return "{mmodule.namespace_for(mclass.visibility)}#{mclass.name}"
599 else if mclass
.intro_mmodule
.mproject
!= mmodule
.mproject
then
600 # public gives 'q::n#p::A'
601 # private gives 'q::n#p::m::A'
602 return "{mmodule.full_name}#{mclass.full_name}"
603 else if mclass
.visibility
> private_visibility
then
604 # public gives 'p::n#A'
605 return "{mmodule.full_name}#{mclass.name}"
607 # private gives 'p::n#::m::A' (redundant p is omitted)
608 return "{mmodule.full_name}#::{mclass.intro_mmodule.name}::{mclass.name}"
612 redef var c_name
is lazy
do
614 return "{mmodule.c_namespace_for(mclass.visibility)}___{mclass.c_name}"
615 else if mclass
.intro_mmodule
.mproject
== mmodule
.mproject
and mclass
.visibility
> private_visibility
then
616 return "{mmodule.c_name}___{mclass.name.to_cmangle}"
618 return "{mmodule.c_name}___{mclass.c_name}"
622 redef fun model
do return mmodule
.model
624 # All declared super-types
625 # FIXME: quite ugly but not better idea yet
626 var supertypes
= new Array[MClassType]
628 # Register some super-types for the class (ie "super SomeType")
630 # The hierarchy must not already be set
631 # REQUIRE: `self.in_hierarchy == null`
632 fun set_supertypes
(supertypes
: Array[MClassType])
634 assert unique_invocation
: self.in_hierarchy
== null
635 var mmodule
= self.mmodule
636 var model
= mmodule
.model
637 var mtype
= self.bound_mtype
639 for supertype
in supertypes
do
640 self.supertypes
.add
(supertype
)
642 # Register in full_type_specialization_hierarchy
643 model
.full_mtype_specialization_hierarchy
.add_edge
(mtype
, supertype
)
644 # Register in intro_type_specialization_hierarchy
645 if mclass
.intro_mmodule
== mmodule
and supertype
.mclass
.intro_mmodule
== mmodule
then
646 model
.intro_mtype_specialization_hierarchy
.add_edge
(mtype
, supertype
)
652 # Collect the super-types (set by set_supertypes) to build the hierarchy
654 # This function can only invoked once by class
655 # REQUIRE: `self.in_hierarchy == null`
656 # ENSURE: `self.in_hierarchy != null`
659 assert unique_invocation
: self.in_hierarchy
== null
660 var model
= mmodule
.model
661 var res
= model
.mclassdef_hierarchy
.add_node
(self)
662 self.in_hierarchy
= res
663 var mtype
= self.bound_mtype
665 # Here we need to connect the mclassdef to its pairs in the mclassdef_hierarchy
666 # The simpliest way is to attach it to collect_mclassdefs
667 for mclassdef
in mtype
.collect_mclassdefs
(mmodule
) do
668 res
.poset
.add_edge
(self, mclassdef
)
672 # The view of the class definition in `mclassdef_hierarchy`
673 var in_hierarchy
: nullable POSetElement[MClassDef] = null
675 # Is the definition the one that introduced `mclass`?
676 fun is_intro
: Bool do return isset mclass
._intro
and mclass
.intro
== self
678 # All properties introduced by the classdef
679 var intro_mproperties
= new Array[MProperty]
681 # All property definitions in the class (introductions and redefinitions)
682 var mpropdefs
= new Array[MPropDef]
685 # A global static type
687 # MType are global to the model; it means that a `MType` is not bound to a
688 # specific `MModule`.
689 # This characteristic helps the reasoning about static types in a program
690 # since a single `MType` object always denote the same type.
692 # However, because a `MType` is global, it does not really have properties
693 # nor have subtypes to a hierarchy since the property and the class hierarchy
694 # depends of a module.
695 # Moreover, virtual types an formal generic parameter types also depends on
696 # a receiver to have sense.
698 # Therefore, most method of the types require a module and an anchor.
699 # The module is used to know what are the classes and the specialization
701 # The anchor is used to know what is the bound of the virtual types and formal
702 # generic parameter types.
704 # MType are not directly usable to get properties. See the `anchor_to` method
705 # and the `MClassType` class.
707 # FIXME: the order of the parameters is not the best. We mus pick on from:
708 # * foo(mmodule, anchor, othertype)
709 # * foo(othertype, anchor, mmodule)
710 # * foo(anchor, mmodule, othertype)
711 # * foo(othertype, mmodule, anchor)
715 redef fun name
do return to_s
717 # Return true if `self` is an subtype of `sup`.
718 # The typing is done using the standard typing policy of Nit.
720 # REQUIRE: `anchor == null implies not self.need_anchor and not sup.need_anchor`
721 # REQUIRE: `anchor != null implies self.can_resolve_for(anchor, null, mmodule) and sup.can_resolve_for(anchor, null, mmodule)`
722 fun is_subtype
(mmodule
: MModule, anchor
: nullable MClassType, sup
: MType): Bool
725 if sub
== sup
then return true
727 #print "1.is {sub} a {sup}? ===="
729 if anchor
== null then
730 assert not sub
.need_anchor
731 assert not sup
.need_anchor
733 # First, resolve the formal types to the simplest equivalent forms in the receiver
734 assert sub
.can_resolve_for
(anchor
, null, mmodule
)
735 sub
= sub
.lookup_fixed
(mmodule
, anchor
)
736 assert sup
.can_resolve_for
(anchor
, null, mmodule
)
737 sup
= sup
.lookup_fixed
(mmodule
, anchor
)
740 # Does `sup` accept null or not?
741 # Discard the nullable marker if it exists
742 var sup_accept_null
= false
743 if sup
isa MNullableType then
744 sup_accept_null
= true
746 else if sup
isa MNotNullType then
748 else if sup
isa MNullType then
749 sup_accept_null
= true
752 # Can `sub` provide null or not?
753 # Thus we can match with `sup_accept_null`
754 # Also discard the nullable marker if it exists
755 var sub_reject_null
= false
756 if sub
isa MNullableType then
757 if not sup_accept_null
then return false
759 else if sub
isa MNotNullType then
760 sub_reject_null
= true
762 else if sub
isa MNullType then
763 return sup_accept_null
765 # Now the case of direct null and nullable is over.
767 # If `sub` is a formal type, then it is accepted if its bound is accepted
768 while sub
isa MFormalType do
769 #print "3.is {sub} a {sup}?"
771 # A unfixed formal type can only accept itself
772 if sub
== sup
then return true
774 assert anchor
!= null
775 sub
= sub
.lookup_bound
(mmodule
, anchor
)
776 if sub_reject_null
then sub
= sub
.as_notnull
778 #print "3.is {sub} a {sup}?"
780 # Manage the second layer of null/nullable
781 if sub
isa MNullableType then
782 if not sup_accept_null
and not sub_reject_null
then return false
784 else if sub
isa MNotNullType then
785 sub_reject_null
= true
787 else if sub
isa MNullType then
788 return sup_accept_null
791 #print "4.is {sub} a {sup}? <- no more resolution"
793 assert sub
isa MClassType else print
"{sub} <? {sub}" # It is the only remaining type
795 # A unfixed formal type can only accept itself
796 if sup
isa MFormalType then
800 if sup
isa MNullType then
801 # `sup` accepts only null
805 assert sup
isa MClassType # It is the only remaining type
807 # Now both are MClassType, we need to dig
809 if sub
== sup
then return true
811 if anchor
== null then anchor
= sub
# UGLY: any anchor will work
812 var resolved_sub
= sub
.anchor_to
(mmodule
, anchor
)
813 var res
= resolved_sub
.collect_mclasses
(mmodule
).has
(sup
.mclass
)
814 if res
== false then return false
815 if not sup
isa MGenericType then return true
816 var sub2
= sub
.supertype_to
(mmodule
, anchor
, sup
.mclass
)
817 assert sub2
.mclass
== sup
.mclass
818 for i
in [0..sup
.mclass
.arity
[ do
819 var sub_arg
= sub2
.arguments
[i
]
820 var sup_arg
= sup
.arguments
[i
]
821 res
= sub_arg
.is_subtype
(mmodule
, anchor
, sup_arg
)
822 if res
== false then return false
827 # The base class type on which self is based
829 # This base type is used to get property (an internally to perform
830 # unsafe type comparison).
832 # Beware: some types (like null) are not based on a class thus this
835 # Basically, this function transform the virtual types and parameter
836 # types to their bounds.
841 # class B super A end
843 # class Y super X end
852 # Map[T,U] anchor_to H #-> Map[B,Y]
854 # Explanation of the example:
855 # In H, T is set to B, because "H super G[B]", and U is bound to Y,
856 # because "redef type U: Y". Therefore, Map[T, U] is bound to
859 # ENSURE: `not self.need_anchor implies result == self`
860 # ENSURE: `not result.need_anchor`
861 fun anchor_to
(mmodule
: MModule, anchor
: MClassType): MType
863 if not need_anchor
then return self
864 assert not anchor
.need_anchor
865 # Just resolve to the anchor and clear all the virtual types
866 var res
= self.resolve_for
(anchor
, null, mmodule
, true)
867 assert not res
.need_anchor
871 # Does `self` contain a virtual type or a formal generic parameter type?
872 # In order to remove those types, you usually want to use `anchor_to`.
873 fun need_anchor
: Bool do return true
875 # Return the supertype when adapted to a class.
877 # In Nit, for each super-class of a type, there is a equivalent super-type.
883 # class H[V] super G[V, Bool] end
885 # H[Int] supertype_to G #-> G[Int, Bool]
888 # REQUIRE: `super_mclass` is a super-class of `self`
889 # REQUIRE: `self.need_anchor implies anchor != null and self.can_resolve_for(anchor, null, mmodule)`
890 # ENSURE: `result.mclass = super_mclass`
891 fun supertype_to
(mmodule
: MModule, anchor
: nullable MClassType, super_mclass
: MClass): MClassType
893 if super_mclass
.arity
== 0 then return super_mclass
.mclass_type
894 if self isa MClassType and self.mclass
== super_mclass
then return self
896 if self.need_anchor
then
897 assert anchor
!= null
898 resolved_self
= self.anchor_to
(mmodule
, anchor
)
902 var supertypes
= resolved_self
.collect_mtypes
(mmodule
)
903 for supertype
in supertypes
do
904 if supertype
.mclass
== super_mclass
then
905 # FIXME: Here, we stop on the first goal. Should we check others and detect inconsistencies?
906 return supertype
.resolve_for
(self, anchor
, mmodule
, false)
912 # Replace formals generic types in self with resolved values in `mtype`
913 # If `cleanup_virtual` is true, then virtual types are also replaced
916 # This function returns self if `need_anchor` is false.
922 # class H[F] super G[F] end
926 # * Array[E].resolve_for(H[Int]) #-> Array[Int]
927 # * Array[E].resolve_for(G[Z], X[Int]) #-> Array[Z]
929 # Explanation of the example:
930 # * Array[E].need_anchor is true because there is a formal generic parameter type E
931 # * E makes sense for H[Int] because E is a formal parameter of G and H specialize G
932 # * Since "H[F] super G[F]", E is in fact F for H
933 # * More specifically, in H[Int], E is Int
934 # * So, in H[Int], Array[E] is Array[Int]
936 # This function is mainly used to inherit a signature.
937 # Because, unlike `anchor_to`, we do not want a full resolution of
938 # a type but only an adapted version of it.
944 # fun foo(e:E):E is abstract
946 # class B super A[Int] end
949 # The signature on foo is (e: E): E
950 # If we resolve the signature for B, we get (e:Int):Int
956 # fun foo(e:E):E is abstract
960 # fun bar do a.foo(x) # <- x is here
964 # The first question is: is foo available on `a`?
966 # The static type of a is `A[Array[F]]`, that is an open type.
967 # in order to find a method `foo`, whe must look at a resolved type.
969 # A[Array[F]].anchor_to(C[nullable Object]) #-> A[Array[nullable Object]]
971 # the method `foo` exists in `A[Array[nullable Object]]`, therefore `foo` exists for `a`.
973 # The next question is: what is the accepted types for `x`?
975 # the signature of `foo` is `foo(e:E)`, thus we must resolve the type E
977 # E.resolve_for(A[Array[F]],C[nullable Object]) #-> Array[F]
979 # The resolution can be done because `E` make sense for the class A (see `can_resolve_for`)
981 # FIXME: the parameter `cleanup_virtual` is just a bad idea, but having
982 # two function instead of one seems also to be a bad idea.
984 # REQUIRE: `can_resolve_for(mtype, anchor, mmodule)`
985 # ENSURE: `not self.need_anchor implies result == self`
986 fun resolve_for
(mtype
: MType, anchor
: nullable MClassType, mmodule
: MModule, cleanup_virtual
: Bool): MType is abstract
988 # Resolve formal type to its verbatim bound.
989 # If the type is not formal, just return self
991 # The result is returned exactly as declared in the "type" property (verbatim).
992 # So it could be another formal type.
994 # In case of conflict, the method aborts.
995 fun lookup_bound
(mmodule
: MModule, resolved_receiver
: MType): MType do return self
997 # Resolve the formal type to its simplest equivalent form.
999 # Formal types are either free or fixed.
1000 # When it is fixed, it means that it is equivalent with a simpler type.
1001 # When a formal type is free, it means that it is only equivalent with itself.
1002 # This method return the most simple equivalent type of `self`.
1004 # This method is mainly used for subtype test in order to sanely compare fixed.
1006 # By default, return self.
1007 # See the redefinitions for specific behavior in each kind of type.
1008 fun lookup_fixed
(mmodule
: MModule, resolved_receiver
: MType): MType do return self
1010 # Can the type be resolved?
1012 # In order to resolve open types, the formal types must make sence.
1022 # E.can_resolve_for(A[Int]) #-> true, E make sense in A
1024 # E.can_resolve_for(B[Int]) #-> false, E does not make sense in B
1026 # B[E].can_resolve_for(A[F], B[Object]) #-> true,
1027 # # B[E] is a red hearing only the E is important,
1028 # # E make sense in A
1031 # REQUIRE: `anchor != null implies not anchor.need_anchor`
1032 # REQUIRE: `mtype.need_anchor implies anchor != null and mtype.can_resolve_for(anchor, null, mmodule)`
1033 # ENSURE: `not self.need_anchor implies result == true`
1034 fun can_resolve_for
(mtype
: MType, anchor
: nullable MClassType, mmodule
: MModule): Bool is abstract
1036 # Return the nullable version of the type
1037 # If the type is already nullable then self is returned
1038 fun as_nullable
: MType
1040 var res
= self.as_nullable_cache
1041 if res
!= null then return res
1042 res
= new MNullableType(self)
1043 self.as_nullable_cache
= res
1047 # Remove the base type of a decorated (proxy) type.
1048 # Is the type is not decorated, then self is returned.
1050 # Most of the time it is used to return the not nullable version of a nullable type.
1051 # In this case, this just remove the `nullable` notation, but the result can still contains null.
1052 # For instance if `self isa MNullType` or self is a formal type bounded by a nullable type.
1053 # If you really want to exclude the `null` value, then use `as_notnull`
1054 fun undecorate
: MType
1059 # Returns the not null version of the type.
1060 # That is `self` minus the `null` value.
1062 # For most types, this return `self`.
1063 # For formal types, this returns a special `MNotNullType`
1064 fun as_notnull
: MType do return self
1066 private var as_nullable_cache
: nullable MType = null
1069 # The depth of the type seen as a tree.
1076 # Formal types have a depth of 1.
1082 # The length of the type seen as a tree.
1089 # Formal types have a length of 1.
1095 # Compute all the classdefs inherited/imported.
1096 # The returned set contains:
1097 # * the class definitions from `mmodule` and its imported modules
1098 # * the class definitions of this type and its super-types
1100 # This function is used mainly internally.
1102 # REQUIRE: `not self.need_anchor`
1103 fun collect_mclassdefs
(mmodule
: MModule): Set[MClassDef] is abstract
1105 # Compute all the super-classes.
1106 # This function is used mainly internally.
1108 # REQUIRE: `not self.need_anchor`
1109 fun collect_mclasses
(mmodule
: MModule): Set[MClass] is abstract
1111 # Compute all the declared super-types.
1112 # Super-types are returned as declared in the classdefs (verbatim).
1113 # This function is used mainly internally.
1115 # REQUIRE: `not self.need_anchor`
1116 fun collect_mtypes
(mmodule
: MModule): Set[MClassType] is abstract
1118 # Is the property in self for a given module
1119 # This method does not filter visibility or whatever
1121 # REQUIRE: `not self.need_anchor`
1122 fun has_mproperty
(mmodule
: MModule, mproperty
: MProperty): Bool
1124 assert not self.need_anchor
1125 return self.collect_mclassdefs
(mmodule
).has
(mproperty
.intro_mclassdef
)
1129 # A type based on a class.
1131 # `MClassType` have properties (see `has_mproperty`).
1135 # The associated class
1138 redef fun model
do return self.mclass
.intro_mmodule
.model
1140 # TODO: private init because strongly bounded to its mclass. see `mclass.mclass_type`
1142 # The formal arguments of the type
1143 # ENSURE: `result.length == self.mclass.arity`
1144 var arguments
= new Array[MType]
1146 redef fun to_s
do return mclass
.to_s
1148 redef fun full_name
do return mclass
.full_name
1150 redef fun c_name
do return mclass
.c_name
1152 redef fun need_anchor
do return false
1154 redef fun anchor_to
(mmodule
: MModule, anchor
: MClassType): MClassType
1156 return super.as(MClassType)
1159 redef fun resolve_for
(mtype
: MType, anchor
: nullable MClassType, mmodule
: MModule, cleanup_virtual
: Bool): MClassType do return self
1161 redef fun can_resolve_for
(mtype
, anchor
, mmodule
) do return true
1163 redef fun collect_mclassdefs
(mmodule
)
1165 assert not self.need_anchor
1166 var cache
= self.collect_mclassdefs_cache
1167 if not cache
.has_key
(mmodule
) then
1168 self.collect_things
(mmodule
)
1170 return cache
[mmodule
]
1173 redef fun collect_mclasses
(mmodule
)
1175 if collect_mclasses_last_module
== mmodule
then return collect_mclasses_last_module_cache
1176 assert not self.need_anchor
1177 var cache
= self.collect_mclasses_cache
1178 if not cache
.has_key
(mmodule
) then
1179 self.collect_things
(mmodule
)
1181 var res
= cache
[mmodule
]
1182 collect_mclasses_last_module
= mmodule
1183 collect_mclasses_last_module_cache
= res
1187 private var collect_mclasses_last_module
: nullable MModule = null
1188 private var collect_mclasses_last_module_cache
: Set[MClass] is noinit
1190 redef fun collect_mtypes
(mmodule
)
1192 assert not self.need_anchor
1193 var cache
= self.collect_mtypes_cache
1194 if not cache
.has_key
(mmodule
) then
1195 self.collect_things
(mmodule
)
1197 return cache
[mmodule
]
1200 # common implementation for `collect_mclassdefs`, `collect_mclasses`, and `collect_mtypes`.
1201 private fun collect_things
(mmodule
: MModule)
1203 var res
= new HashSet[MClassDef]
1204 var seen
= new HashSet[MClass]
1205 var types
= new HashSet[MClassType]
1206 seen
.add
(self.mclass
)
1207 var todo
= [self.mclass
]
1208 while not todo
.is_empty
do
1209 var mclass
= todo
.pop
1210 #print "process {mclass}"
1211 for mclassdef
in mclass
.mclassdefs
do
1212 if not mmodule
.in_importation
<= mclassdef
.mmodule
then continue
1213 #print " process {mclassdef}"
1215 for supertype
in mclassdef
.supertypes
do
1216 types
.add
(supertype
)
1217 var superclass
= supertype
.mclass
1218 if seen
.has
(superclass
) then continue
1219 #print " add {superclass}"
1220 seen
.add
(superclass
)
1221 todo
.add
(superclass
)
1225 collect_mclassdefs_cache
[mmodule
] = res
1226 collect_mclasses_cache
[mmodule
] = seen
1227 collect_mtypes_cache
[mmodule
] = types
1230 private var collect_mclassdefs_cache
= new HashMap[MModule, Set[MClassDef]]
1231 private var collect_mclasses_cache
= new HashMap[MModule, Set[MClass]]
1232 private var collect_mtypes_cache
= new HashMap[MModule, Set[MClassType]]
1236 # A type based on a generic class.
1237 # A generic type a just a class with additional formal generic arguments.
1243 # TODO: private init because strongly bounded to its mclass. see `mclass.get_mtype`
1247 assert self.mclass
.arity
== arguments
.length
1249 self.need_anchor
= false
1250 for t
in arguments
do
1251 if t
.need_anchor
then
1252 self.need_anchor
= true
1257 self.to_s
= "{mclass}[{arguments.join(", ")}]"
1260 # The short-name of the class, then the full-name of each type arguments within brackets.
1261 # Example: `"Map[String, List[Int]]"`
1262 redef var to_s
: String is noinit
1264 # The full-name of the class, then the full-name of each type arguments within brackets.
1265 # Example: `"standard::Map[standard::String, standard::List[standard::Int]]"`
1266 redef var full_name
is lazy
do
1267 var args
= new Array[String]
1268 for t
in arguments
do
1269 args
.add t
.full_name
1271 return "{mclass.full_name}[{args.join(", ")}]"
1274 redef var c_name
is lazy
do
1275 var res
= mclass
.c_name
1276 # Note: because the arity is known, a prefix notation is enough
1277 for t
in arguments
do
1284 redef var need_anchor
: Bool is noinit
1286 redef fun resolve_for
(mtype
, anchor
, mmodule
, cleanup_virtual
)
1288 if not need_anchor
then return self
1289 assert can_resolve_for
(mtype
, anchor
, mmodule
)
1290 var types
= new Array[MType]
1291 for t
in arguments
do
1292 types
.add
(t
.resolve_for
(mtype
, anchor
, mmodule
, cleanup_virtual
))
1294 return mclass
.get_mtype
(types
)
1297 redef fun can_resolve_for
(mtype
, anchor
, mmodule
)
1299 if not need_anchor
then return true
1300 for t
in arguments
do
1301 if not t
.can_resolve_for
(mtype
, anchor
, mmodule
) then return false
1310 for a
in self.arguments
do
1312 if d
> dmax
then dmax
= d
1320 for a
in self.arguments
do
1327 # A formal type (either virtual of parametric).
1329 # The main issue with formal types is that they offer very little information on their own
1330 # and need a context (anchor and mmodule) to be useful.
1331 abstract class MFormalType
1334 redef var as_notnull
= new MNotNullType(self) is lazy
1337 # A virtual formal type.
1341 # The property associated with the type.
1342 # Its the definitions of this property that determine the bound or the virtual type.
1343 var mproperty
: MVirtualTypeProp
1345 redef fun model
do return self.mproperty
.intro_mclassdef
.mmodule
.model
1347 redef fun lookup_bound
(mmodule
: MModule, resolved_receiver
: MType): MType
1349 return lookup_single_definition
(mmodule
, resolved_receiver
).bound
.as(not null)
1352 private fun lookup_single_definition
(mmodule
: MModule, resolved_receiver
: MType): MVirtualTypeDef
1354 assert not resolved_receiver
.need_anchor
1355 var props
= self.mproperty
.lookup_definitions
(mmodule
, resolved_receiver
)
1356 if props
.is_empty
then
1358 else if props
.length
== 1 then
1361 var types
= new ArraySet[MType]
1362 var res
= props
.first
1364 types
.add
(p
.bound
.as(not null))
1365 if not res
.is_fixed
then res
= p
1367 if types
.length
== 1 then
1373 # A VT is fixed when:
1374 # * the VT is (re-)defined with the annotation `is fixed`
1375 # * the VT is (indirectly) bound to an enum class (see `enum_kind`) since there is no subtype possible
1376 # * the receiver is an enum class since there is no subtype possible
1377 redef fun lookup_fixed
(mmodule
: MModule, resolved_receiver
: MType): MType
1379 assert not resolved_receiver
.need_anchor
1380 resolved_receiver
= resolved_receiver
.undecorate
1381 assert resolved_receiver
isa MClassType # It is the only remaining type
1383 var prop
= lookup_single_definition
(mmodule
, resolved_receiver
)
1384 var res
= prop
.bound
.as(not null)
1386 # Recursively lookup the fixed result
1387 res
= res
.lookup_fixed
(mmodule
, resolved_receiver
)
1389 # 1. For a fixed VT, return the resolved bound
1390 if prop
.is_fixed
then return res
1392 # 2. For a enum boud, return the bound
1393 if res
isa MClassType and res
.mclass
.kind
== enum_kind
then return res
1395 # 3. for a enum receiver return the bound
1396 if resolved_receiver
.mclass
.kind
== enum_kind
then return res
1401 redef fun resolve_for
(mtype
, anchor
, mmodule
, cleanup_virtual
)
1403 if not cleanup_virtual
then return self
1404 assert can_resolve_for
(mtype
, anchor
, mmodule
)
1405 # self is a virtual type declared (or inherited) in mtype
1406 # The point of the function it to get the bound of the virtual type that make sense for mtype
1407 # But because mtype is maybe a virtual/formal type, we need to get a real receiver first
1408 #print "{class_name}: {self}/{mtype}/{anchor}?"
1409 var resolved_receiver
1410 if mtype
.need_anchor
then
1411 assert anchor
!= null
1412 resolved_receiver
= mtype
.resolve_for
(anchor
, null, mmodule
, true)
1414 resolved_receiver
= mtype
1416 # Now, we can get the bound
1417 var verbatim_bound
= lookup_bound
(mmodule
, resolved_receiver
)
1418 # The bound is exactly as declared in the "type" property, so we must resolve it again
1419 var res
= verbatim_bound
.resolve_for
(mtype
, anchor
, mmodule
, cleanup_virtual
)
1424 redef fun can_resolve_for
(mtype
, anchor
, mmodule
)
1426 if mtype
.need_anchor
then
1427 assert anchor
!= null
1428 mtype
= mtype
.anchor_to
(mmodule
, anchor
)
1430 return mtype
.has_mproperty
(mmodule
, mproperty
)
1433 redef fun to_s
do return self.mproperty
.to_s
1435 redef fun full_name
do return self.mproperty
.full_name
1437 redef fun c_name
do return self.mproperty
.c_name
1440 # The type associated to a formal parameter generic type of a class
1442 # Each parameter type is associated to a specific class.
1443 # It means that all refinements of a same class "share" the parameter type,
1444 # but that a generic subclass has its own parameter types.
1446 # However, in the sense of the meta-model, a parameter type of a class is
1447 # a valid type in a subclass. The "in the sense of the meta-model" is
1448 # important because, in the Nit language, the programmer cannot refers
1449 # directly to the parameter types of the super-classes.
1454 # fun e: E is abstract
1460 # In the class definition B[F], `F` is a valid type but `E` is not.
1461 # However, `self.e` is a valid method call, and the signature of `e` is
1464 # Note that parameter types are shared among class refinements.
1465 # Therefore parameter only have an internal name (see `to_s` for details).
1466 class MParameterType
1469 # The generic class where the parameter belong
1472 redef fun model
do return self.mclass
.intro_mmodule
.model
1474 # The position of the parameter (0 for the first parameter)
1475 # FIXME: is `position` a better name?
1480 redef fun to_s
do return name
1482 redef var full_name
is lazy
do return "{mclass.full_name}::{name}"
1484 redef var c_name
is lazy
do return mclass
.c_name
+ "__" + "#{name}".to_cmangle
1486 redef fun lookup_bound
(mmodule
: MModule, resolved_receiver
: MType): MType
1488 assert not resolved_receiver
.need_anchor
1489 resolved_receiver
= resolved_receiver
.undecorate
1490 assert resolved_receiver
isa MClassType # It is the only remaining type
1491 var goalclass
= self.mclass
1492 if resolved_receiver
.mclass
== goalclass
then
1493 return resolved_receiver
.arguments
[self.rank
]
1495 var supertypes
= resolved_receiver
.collect_mtypes
(mmodule
)
1496 for t
in supertypes
do
1497 if t
.mclass
== goalclass
then
1498 # Yeah! c specialize goalclass with a "super `t'". So the question is what is the argument of f
1499 # FIXME: Here, we stop on the first goal. Should we check others and detect inconsistencies?
1500 var res
= t
.arguments
[self.rank
]
1507 # A PT is fixed when:
1508 # * Its bound is a enum class (see `enum_kind`).
1509 # The PT is just useless, but it is still a case.
1510 # * More usually, the `resolved_receiver` is a subclass of `self.mclass`,
1511 # so it is necessarily fixed in a `super` clause, either with a normal type
1512 # or with another PT.
1513 # See `resolve_for` for examples about related issues.
1514 redef fun lookup_fixed
(mmodule
: MModule, resolved_receiver
: MType): MType
1516 assert not resolved_receiver
.need_anchor
1517 resolved_receiver
= resolved_receiver
.undecorate
1518 assert resolved_receiver
isa MClassType # It is the only remaining type
1519 var res
= self.resolve_for
(resolved_receiver
.mclass
.mclass_type
, resolved_receiver
, mmodule
, false)
1523 redef fun resolve_for
(mtype
, anchor
, mmodule
, cleanup_virtual
)
1525 assert can_resolve_for
(mtype
, anchor
, mmodule
)
1526 #print "{class_name}: {self}/{mtype}/{anchor}?"
1528 if mtype
isa MGenericType and mtype
.mclass
== self.mclass
then
1529 var res
= mtype
.arguments
[self.rank
]
1530 if anchor
!= null and res
.need_anchor
then
1531 # Maybe the result can be resolved more if are bound to a final class
1532 var r2
= res
.anchor_to
(mmodule
, anchor
)
1533 if r2
isa MClassType and r2
.mclass
.kind
== enum_kind
then return r2
1538 # self is a parameter type of mtype (or of a super-class of mtype)
1539 # The point of the function it to get the bound of the virtual type that make sense for mtype
1540 # But because mtype is maybe a virtual/formal type, we need to get a real receiver first
1541 # FIXME: What happens here is far from clear. Thus this part must be validated and clarified
1542 var resolved_receiver
1543 if mtype
.need_anchor
then
1544 assert anchor
!= null
1545 resolved_receiver
= mtype
.resolve_for
(anchor
.mclass
.mclass_type
, anchor
, mmodule
, true)
1547 resolved_receiver
= mtype
1549 if resolved_receiver
isa MNullableType then resolved_receiver
= resolved_receiver
.mtype
1550 if resolved_receiver
isa MParameterType then
1551 assert resolved_receiver
.mclass
== anchor
.mclass
1552 resolved_receiver
= anchor
.arguments
[resolved_receiver
.rank
]
1553 if resolved_receiver
isa MNullableType then resolved_receiver
= resolved_receiver
.mtype
1555 assert resolved_receiver
isa MClassType # It is the only remaining type
1557 # Eh! The parameter is in the current class.
1558 # So we return the corresponding argument, no mater what!
1559 if resolved_receiver
.mclass
== self.mclass
then
1560 var res
= resolved_receiver
.arguments
[self.rank
]
1561 #print "{class_name}: {self}/{mtype}/{anchor} -> direct {res}"
1565 if resolved_receiver
.need_anchor
then
1566 assert anchor
!= null
1567 resolved_receiver
= resolved_receiver
.resolve_for
(anchor
, null, mmodule
, false)
1569 # Now, we can get the bound
1570 var verbatim_bound
= lookup_bound
(mmodule
, resolved_receiver
)
1571 # The bound is exactly as declared in the "type" property, so we must resolve it again
1572 var res
= verbatim_bound
.resolve_for
(mtype
, anchor
, mmodule
, cleanup_virtual
)
1574 #print "{class_name}: {self}/{mtype}/{anchor} -> indirect {res}"
1579 redef fun can_resolve_for
(mtype
, anchor
, mmodule
)
1581 if mtype
.need_anchor
then
1582 assert anchor
!= null
1583 mtype
= mtype
.anchor_to
(mmodule
, anchor
)
1585 return mtype
.collect_mclassdefs
(mmodule
).has
(mclass
.intro
)
1589 # A type that decorates another type.
1591 # The point of this class is to provide a common implementation of sevices that just forward to the original type.
1592 # Specific decorator are expected to redefine (or to extend) the default implementation as this suit them.
1593 abstract class MProxyType
1598 redef fun model
do return self.mtype
.model
1599 redef fun need_anchor
do return mtype
.need_anchor
1600 redef fun as_nullable
do return mtype
.as_nullable
1601 redef fun as_notnull
do return mtype
.as_notnull
1602 redef fun undecorate
do return mtype
.undecorate
1603 redef fun resolve_for
(mtype
, anchor
, mmodule
, cleanup_virtual
)
1605 var res
= self.mtype
.resolve_for
(mtype
, anchor
, mmodule
, cleanup_virtual
)
1609 redef fun can_resolve_for
(mtype
, anchor
, mmodule
)
1611 return self.mtype
.can_resolve_for
(mtype
, anchor
, mmodule
)
1614 redef fun lookup_fixed
(mmodule
, resolved_receiver
)
1616 var t
= mtype
.lookup_fixed
(mmodule
, resolved_receiver
)
1620 redef fun depth
do return self.mtype
.depth
1622 redef fun length
do return self.mtype
.length
1624 redef fun collect_mclassdefs
(mmodule
)
1626 assert not self.need_anchor
1627 return self.mtype
.collect_mclassdefs
(mmodule
)
1630 redef fun collect_mclasses
(mmodule
)
1632 assert not self.need_anchor
1633 return self.mtype
.collect_mclasses
(mmodule
)
1636 redef fun collect_mtypes
(mmodule
)
1638 assert not self.need_anchor
1639 return self.mtype
.collect_mtypes
(mmodule
)
1643 # A type prefixed with "nullable"
1649 self.to_s
= "nullable {mtype}"
1652 redef var to_s
: String is noinit
1654 redef var full_name
is lazy
do return "nullable {mtype.full_name}"
1656 redef var c_name
is lazy
do return "nullable__{mtype.c_name}"
1658 redef fun as_nullable
do return self
1659 redef fun resolve_for
(mtype
, anchor
, mmodule
, cleanup_virtual
)
1662 return res
.as_nullable
1665 # Efficiently returns `mtype.lookup_fixed(mmodule, resolved_receiver).as_nullable`
1666 redef fun lookup_fixed
(mmodule
, resolved_receiver
)
1669 if t
== mtype
then return self
1670 return t
.as_nullable
1674 # A non-null version of a formal type.
1676 # When a formal type in bounded to a nullable type, this is the type of the not null version of it.
1680 redef fun to_s
do return "not null {mtype}"
1681 redef var full_name
is lazy
do return "not null {mtype.full_name}"
1682 redef var c_name
is lazy
do return "notnull__{mtype.c_name}"
1684 redef fun as_notnull
do return self
1686 redef fun resolve_for
(mtype
, anchor
, mmodule
, cleanup_virtual
)
1689 return res
.as_notnull
1692 # Efficiently returns `mtype.lookup_fixed(mmodule, resolved_receiver).as_notnull`
1693 redef fun lookup_fixed
(mmodule
, resolved_receiver
)
1696 if t
== mtype
then return self
1701 # The type of the only value null
1703 # The is only one null type per model, see `MModel::null_type`.
1706 redef var model
: Model
1707 redef fun to_s
do return "null"
1708 redef fun full_name
do return "null"
1709 redef fun c_name
do return "null"
1710 redef fun as_nullable
do return self
1712 redef var as_notnull
= new MBottomType(model
) is lazy
1713 redef fun need_anchor
do return false
1714 redef fun resolve_for
(mtype
, anchor
, mmodule
, cleanup_virtual
) do return self
1715 redef fun can_resolve_for
(mtype
, anchor
, mmodule
) do return true
1717 redef fun collect_mclassdefs
(mmodule
) do return new HashSet[MClassDef]
1719 redef fun collect_mclasses
(mmodule
) do return new HashSet[MClass]
1721 redef fun collect_mtypes
(mmodule
) do return new HashSet[MClassType]
1724 # The special universal most specific type.
1726 # This type is intended to be only used internally for type computation or analysis and should not be exposed to the user.
1727 # The bottom type can de used to denote things that are absurd, dead, or the absence of knowledge.
1729 # Semantically it is the singleton `null.as_notnull`.
1732 redef var model
: Model
1733 redef fun to_s
do return "bottom"
1734 redef fun full_name
do return "bottom"
1735 redef fun c_name
do return "bottom"
1736 redef fun as_nullable
do return model
.null_type
1737 redef fun as_notnull
do return self
1738 redef fun need_anchor
do return false
1739 redef fun resolve_for
(mtype
, anchor
, mmodule
, cleanup_virtual
) do return self
1740 redef fun can_resolve_for
(mtype
, anchor
, mmodule
) do return true
1742 redef fun collect_mclassdefs
(mmodule
) do return new HashSet[MClassDef]
1744 redef fun collect_mclasses
(mmodule
) do return new HashSet[MClass]
1746 redef fun collect_mtypes
(mmodule
) do return new HashSet[MClassType]
1749 # A signature of a method
1753 # The each parameter (in order)
1754 var mparameters
: Array[MParameter]
1756 # Returns a parameter named `name`, if any.
1757 fun mparameter_by_name
(name
: String): nullable MParameter
1759 for p
in mparameters
do
1760 if p
.name
== name
then return p
1765 # The return type (null for a procedure)
1766 var return_mtype
: nullable MType
1771 var t
= self.return_mtype
1772 if t
!= null then dmax
= t
.depth
1773 for p
in mparameters
do
1774 var d
= p
.mtype
.depth
1775 if d
> dmax
then dmax
= d
1783 var t
= self.return_mtype
1784 if t
!= null then res
+= t
.length
1785 for p
in mparameters
do
1786 res
+= p
.mtype
.length
1791 # REQUIRE: 1 <= mparameters.count p -> p.is_vararg
1794 var vararg_rank
= -1
1795 for i
in [0..mparameters
.length
[ do
1796 var parameter
= mparameters
[i
]
1797 if parameter
.is_vararg
then
1798 assert vararg_rank
== -1
1802 self.vararg_rank
= vararg_rank
1805 # The rank of the ellipsis (`...`) for vararg (starting from 0).
1806 # value is -1 if there is no vararg.
1807 # Example: for "(a: Int, b: Bool..., c: Char)" #-> vararg_rank=1
1808 var vararg_rank
: Int is noinit
1810 # The number of parameters
1811 fun arity
: Int do return mparameters
.length
1813 # The number of non-default parameters
1815 # The number of default parameters is then `arity-min_arity`.
1817 # Note that there cannot be both varargs and default prameters, thus
1818 # if `vararg_rank != -1` then `min_arity` == `arity`
1821 if vararg_rank
!= -1 then return arity
1823 for p
in mparameters
do
1824 if not p
.is_default
then res
+= 1
1831 var b
= new FlatBuffer
1832 if not mparameters
.is_empty
then
1834 for i
in [0..mparameters
.length
[ do
1835 var mparameter
= mparameters
[i
]
1836 if i
> 0 then b
.append
(", ")
1837 b
.append
(mparameter
.name
)
1839 b
.append
(mparameter
.mtype
.to_s
)
1840 if mparameter
.is_vararg
then
1846 var ret
= self.return_mtype
1854 redef fun resolve_for
(mtype
: MType, anchor
: nullable MClassType, mmodule
: MModule, cleanup_virtual
: Bool): MSignature
1856 var params
= new Array[MParameter]
1857 for p
in self.mparameters
do
1858 params
.add
(p
.resolve_for
(mtype
, anchor
, mmodule
, cleanup_virtual
))
1860 var ret
= self.return_mtype
1862 ret
= ret
.resolve_for
(mtype
, anchor
, mmodule
, cleanup_virtual
)
1864 var res
= new MSignature(params
, ret
)
1869 # A parameter in a signature
1873 # The name of the parameter
1874 redef var name
: String
1876 # The static type of the parameter
1879 # Is the parameter a vararg?
1882 # Is the parameter a default one?
1883 var is_default
: Bool
1888 return "{name}: {mtype}..."
1890 return "{name}: {mtype}"
1894 # Returns a new parameter with the `mtype` resolved.
1895 # See `MType::resolve_for` for details.
1896 fun resolve_for
(mtype
: MType, anchor
: nullable MClassType, mmodule
: MModule, cleanup_virtual
: Bool): MParameter
1898 if not self.mtype
.need_anchor
then return self
1899 var newtype
= self.mtype
.resolve_for
(mtype
, anchor
, mmodule
, cleanup_virtual
)
1900 var res
= new MParameter(self.name
, newtype
, self.is_vararg
, self.is_default
)
1904 redef fun model
do return mtype
.model
1907 # A service (global property) that generalize method, attribute, etc.
1909 # `MProperty` are global to the model; it means that a `MProperty` is not bound
1910 # to a specific `MModule` nor a specific `MClass`.
1912 # A MProperty gather definitions (see `mpropdefs`) ; one for the introduction
1913 # and the other in subclasses and in refinements.
1915 # A `MProperty` is used to denotes services in polymorphic way (ie. independent
1916 # of any dynamic type).
1917 # For instance, a call site "x.foo" is associated to a `MProperty`.
1918 abstract class MProperty
1921 # The associated MPropDef subclass.
1922 # The two specialization hierarchy are symmetric.
1923 type MPROPDEF: MPropDef
1925 # The classdef that introduce the property
1926 # While a property is not bound to a specific module, or class,
1927 # the introducing mclassdef is used for naming and visibility
1928 var intro_mclassdef
: MClassDef
1930 # The (short) name of the property
1931 redef var name
: String
1933 # The canonical name of the property.
1935 # It is the short-`name` prefixed by the short-name of the class and the full-name of the module.
1936 # Example: "my_project::my_module::MyClass::my_method"
1937 redef var full_name
is lazy
do
1938 return "{intro_mclassdef.mmodule.namespace_for(visibility)}::{intro_mclassdef.mclass.name}::{name}"
1941 redef var c_name
is lazy
do
1942 # FIXME use `namespace_for`
1943 return "{intro_mclassdef.mmodule.c_name}__{intro_mclassdef.mclass.name.to_cmangle}__{name.to_cmangle}"
1946 # The visibility of the property
1947 var visibility
: MVisibility
1949 # Is the property usable as an initializer?
1950 var is_autoinit
= false is writable
1954 intro_mclassdef
.intro_mproperties
.add
(self)
1955 var model
= intro_mclassdef
.mmodule
.model
1956 model
.mproperties_by_name
.add_one
(name
, self)
1957 model
.mproperties
.add
(self)
1960 # All definitions of the property.
1961 # The first is the introduction,
1962 # The other are redefinitions (in refinements and in subclasses)
1963 var mpropdefs
= new Array[MPROPDEF]
1965 # The definition that introduces the property.
1967 # Warning: such a definition may not exist in the early life of the object.
1968 # In this case, the method will abort.
1969 var intro
: MPROPDEF is noinit
1971 redef fun model
do return intro
.model
1974 redef fun to_s
do return name
1976 # Return the most specific property definitions defined or inherited by a type.
1977 # The selection knows that refinement is stronger than specialization;
1978 # however, in case of conflict more than one property are returned.
1979 # If mtype does not know mproperty then an empty array is returned.
1981 # If you want the really most specific property, then look at `lookup_first_definition`
1983 # REQUIRE: `not mtype.need_anchor` to simplify the API (no `anchor` parameter)
1984 # ENSURE: `not mtype.has_mproperty(mmodule, self) == result.is_empty`
1985 fun lookup_definitions
(mmodule
: MModule, mtype
: MType): Array[MPROPDEF]
1987 assert not mtype
.need_anchor
1988 mtype
= mtype
.undecorate
1990 var cache
= self.lookup_definitions_cache
[mmodule
, mtype
]
1991 if cache
!= null then return cache
1993 #print "select prop {mproperty} for {mtype} in {self}"
1994 # First, select all candidates
1995 var candidates
= new Array[MPROPDEF]
1996 for mpropdef
in self.mpropdefs
do
1997 # If the definition is not imported by the module, then skip
1998 if not mmodule
.in_importation
<= mpropdef
.mclassdef
.mmodule
then continue
1999 # If the definition is not inherited by the type, then skip
2000 if not mtype
.is_subtype
(mmodule
, null, mpropdef
.mclassdef
.bound_mtype
) then continue
2002 candidates
.add
(mpropdef
)
2004 # Fast track for only one candidate
2005 if candidates
.length
<= 1 then
2006 self.lookup_definitions_cache
[mmodule
, mtype
] = candidates
2010 # Second, filter the most specific ones
2011 return select_most_specific
(mmodule
, candidates
)
2014 private var lookup_definitions_cache
= new HashMap2[MModule, MType, Array[MPROPDEF]]
2016 # Return the most specific property definitions inherited by a type.
2017 # The selection knows that refinement is stronger than specialization;
2018 # however, in case of conflict more than one property are returned.
2019 # If mtype does not know mproperty then an empty array is returned.
2021 # If you want the really most specific property, then look at `lookup_next_definition`
2023 # REQUIRE: `not mtype.need_anchor` to simplify the API (no `anchor` parameter)
2024 # ENSURE: `not mtype.has_mproperty(mmodule, self) implies result.is_empty`
2025 fun lookup_super_definitions
(mmodule
: MModule, mtype
: MType): Array[MPROPDEF]
2027 assert not mtype
.need_anchor
2028 mtype
= mtype
.undecorate
2030 # First, select all candidates
2031 var candidates
= new Array[MPROPDEF]
2032 for mpropdef
in self.mpropdefs
do
2033 # If the definition is not imported by the module, then skip
2034 if not mmodule
.in_importation
<= mpropdef
.mclassdef
.mmodule
then continue
2035 # If the definition is not inherited by the type, then skip
2036 if not mtype
.is_subtype
(mmodule
, null, mpropdef
.mclassdef
.bound_mtype
) then continue
2037 # If the definition is defined by the type, then skip (we want the super, so e skip the current)
2038 if mtype
== mpropdef
.mclassdef
.bound_mtype
and mmodule
== mpropdef
.mclassdef
.mmodule
then continue
2040 candidates
.add
(mpropdef
)
2042 # Fast track for only one candidate
2043 if candidates
.length
<= 1 then return candidates
2045 # Second, filter the most specific ones
2046 return select_most_specific
(mmodule
, candidates
)
2049 # Return an array containing olny the most specific property definitions
2050 # This is an helper function for `lookup_definitions` and `lookup_super_definitions`
2051 private fun select_most_specific
(mmodule
: MModule, candidates
: Array[MPROPDEF]): Array[MPROPDEF]
2053 var res
= new Array[MPROPDEF]
2054 for pd1
in candidates
do
2055 var cd1
= pd1
.mclassdef
2058 for pd2
in candidates
do
2059 if pd2
== pd1
then continue # do not compare with self!
2060 var cd2
= pd2
.mclassdef
2062 if c2
.mclass_type
== c1
.mclass_type
then
2063 if cd2
.mmodule
.in_importation
< cd1
.mmodule
then
2064 # cd2 refines cd1; therefore we skip pd1
2068 else if cd2
.bound_mtype
.is_subtype
(mmodule
, null, cd1
.bound_mtype
) and cd2
.bound_mtype
!= cd1
.bound_mtype
then
2069 # cd2 < cd1; therefore we skip pd1
2078 if res
.is_empty
then
2079 print
"All lost! {candidates.join(", ")}"
2080 # FIXME: should be abort!
2085 # Return the most specific definition in the linearization of `mtype`.
2087 # If you want to know the next properties in the linearization,
2088 # look at `MPropDef::lookup_next_definition`.
2090 # FIXME: the linearization is still unspecified
2092 # REQUIRE: `not mtype.need_anchor` to simplify the API (no `anchor` parameter)
2093 # REQUIRE: `mtype.has_mproperty(mmodule, self)`
2094 fun lookup_first_definition
(mmodule
: MModule, mtype
: MType): MPROPDEF
2096 return lookup_all_definitions
(mmodule
, mtype
).first
2099 # Return all definitions in a linearization order
2100 # Most specific first, most general last
2102 # REQUIRE: `not mtype.need_anchor` to simplify the API (no `anchor` parameter)
2103 # REQUIRE: `mtype.has_mproperty(mmodule, self)`
2104 fun lookup_all_definitions
(mmodule
: MModule, mtype
: MType): Array[MPROPDEF]
2106 mtype
= mtype
.undecorate
2108 var cache
= self.lookup_all_definitions_cache
[mmodule
, mtype
]
2109 if cache
!= null then return cache
2111 assert not mtype
.need_anchor
2112 assert mtype
.has_mproperty
(mmodule
, self)
2114 #print "select prop {mproperty} for {mtype} in {self}"
2115 # First, select all candidates
2116 var candidates
= new Array[MPROPDEF]
2117 for mpropdef
in self.mpropdefs
do
2118 # If the definition is not imported by the module, then skip
2119 if not mmodule
.in_importation
<= mpropdef
.mclassdef
.mmodule
then continue
2120 # If the definition is not inherited by the type, then skip
2121 if not mtype
.is_subtype
(mmodule
, null, mpropdef
.mclassdef
.bound_mtype
) then continue
2123 candidates
.add
(mpropdef
)
2125 # Fast track for only one candidate
2126 if candidates
.length
<= 1 then
2127 self.lookup_all_definitions_cache
[mmodule
, mtype
] = candidates
2131 mmodule
.linearize_mpropdefs
(candidates
)
2132 candidates
= candidates
.reversed
2133 self.lookup_all_definitions_cache
[mmodule
, mtype
] = candidates
2137 private var lookup_all_definitions_cache
= new HashMap2[MModule, MType, Array[MPROPDEF]]
2144 redef type MPROPDEF: MMethodDef
2146 # Is the property defined at the top_level of the module?
2147 # Currently such a property are stored in `Object`
2148 var is_toplevel
: Bool = false is writable
2150 # Is the property a constructor?
2151 # Warning, this property can be inherited by subclasses with or without being a constructor
2152 # therefore, you should use `is_init_for` the verify if the property is a legal constructor for a given class
2153 var is_init
: Bool = false is writable
2155 # The constructor is a (the) root init with empty signature but a set of initializers
2156 var is_root_init
: Bool = false is writable
2158 # Is the property a 'new' constructor?
2159 var is_new
: Bool = false is writable
2161 # Is the property a legal constructor for a given class?
2162 # As usual, visibility is not considered.
2163 # FIXME not implemented
2164 fun is_init_for
(mclass
: MClass): Bool
2170 # A global attribute
2174 redef type MPROPDEF: MAttributeDef
2178 # A global virtual type
2179 class MVirtualTypeProp
2182 redef type MPROPDEF: MVirtualTypeDef
2184 # The formal type associated to the virtual type property
2185 var mvirtualtype
= new MVirtualType(self)
2188 # A definition of a property (local property)
2190 # Unlike `MProperty`, a `MPropDef` is a local definition that belong to a
2191 # specific class definition (which belong to a specific module)
2192 abstract class MPropDef
2195 # The associated `MProperty` subclass.
2196 # the two specialization hierarchy are symmetric
2197 type MPROPERTY: MProperty
2200 type MPROPDEF: MPropDef
2202 # The class definition where the property definition is
2203 var mclassdef
: MClassDef
2205 # The associated global property
2206 var mproperty
: MPROPERTY
2208 # The origin of the definition
2209 var location
: Location
2213 mclassdef
.mpropdefs
.add
(self)
2214 mproperty
.mpropdefs
.add
(self)
2215 if mproperty
.intro_mclassdef
== mclassdef
then
2216 assert not isset mproperty
._intro
2217 mproperty
.intro
= self
2219 self.to_s
= "{mclassdef}#{mproperty}"
2222 # Actually the name of the `mproperty`
2223 redef fun name
do return mproperty
.name
2225 # The full-name of mpropdefs combine the information about the `classdef` and the `mproperty`.
2227 # Therefore the combination of identifiers is awful,
2228 # the worst case being
2230 # * a property "p::m::A::x"
2231 # * redefined in a refinement of a class "q::n::B"
2232 # * in a module "r::o"
2233 # * so "r::o#q::n::B#p::m::A::x"
2235 # Fortunately, the full-name is simplified when entities are repeated.
2236 # For the previous case, the simplest form is "p#A#x".
2237 redef var full_name
is lazy
do
2238 var res
= new FlatBuffer
2240 # The first part is the mclassdef. Worst case is "r::o#q::n::B"
2241 res
.append mclassdef
.full_name
2245 if mclassdef
.mclass
== mproperty
.intro_mclassdef
.mclass
then
2246 # intro are unambiguous in a class
2249 # Just try to simplify each part
2250 if mclassdef
.mmodule
.mproject
!= mproperty
.intro_mclassdef
.mmodule
.mproject
then
2251 # precise "p::m" only if "p" != "r"
2252 res
.append mproperty
.intro_mclassdef
.mmodule
.full_name
2254 else if mproperty
.visibility
<= private_visibility
then
2255 # Same project ("p"=="q"), but private visibility,
2256 # does the module part ("::m") need to be displayed
2257 if mclassdef
.mmodule
.namespace_for
(mclassdef
.mclass
.visibility
) != mproperty
.intro_mclassdef
.mmodule
.mproject
then
2259 res
.append mproperty
.intro_mclassdef
.mmodule
.name
2263 if mclassdef
.mclass
!= mproperty
.intro_mclassdef
.mclass
then
2264 # precise "B" only if not the same class than "A"
2265 res
.append mproperty
.intro_mclassdef
.name
2268 # Always use the property name "x"
2269 res
.append mproperty
.name
2274 redef var c_name
is lazy
do
2275 var res
= new FlatBuffer
2276 res
.append mclassdef
.c_name
2278 if mclassdef
.mclass
== mproperty
.intro_mclassdef
.mclass
then
2279 res
.append name
.to_cmangle
2281 if mclassdef
.mmodule
!= mproperty
.intro_mclassdef
.mmodule
then
2282 res
.append mproperty
.intro_mclassdef
.mmodule
.c_name
2285 if mclassdef
.mclass
!= mproperty
.intro_mclassdef
.mclass
then
2286 res
.append mproperty
.intro_mclassdef
.name
.to_cmangle
2289 res
.append mproperty
.name
.to_cmangle
2294 redef fun model
do return mclassdef
.model
2296 # Internal name combining the module, the class and the property
2297 # Example: "mymodule#MyClass#mymethod"
2298 redef var to_s
: String is noinit
2300 # Is self the definition that introduce the property?
2301 fun is_intro
: Bool do return mproperty
.intro
== self
2303 # Return the next definition in linearization of `mtype`.
2305 # This method is used to determine what method is called by a super.
2307 # REQUIRE: `not mtype.need_anchor`
2308 fun lookup_next_definition
(mmodule
: MModule, mtype
: MType): MPROPDEF
2310 assert not mtype
.need_anchor
2312 var mpropdefs
= self.mproperty
.lookup_all_definitions
(mmodule
, mtype
)
2313 var i
= mpropdefs
.iterator
2314 while i
.is_ok
and i
.item
!= self do i
.next
2315 assert has_property
: i
.is_ok
2317 assert has_next_property
: i
.is_ok
2322 # A local definition of a method
2326 redef type MPROPERTY: MMethod
2327 redef type MPROPDEF: MMethodDef
2329 # The signature attached to the property definition
2330 var msignature
: nullable MSignature = null is writable
2332 # The signature attached to the `new` call on a root-init
2333 # This is a concatenation of the signatures of the initializers
2335 # REQUIRE `mproperty.is_root_init == (new_msignature != null)`
2336 var new_msignature
: nullable MSignature = null is writable
2338 # List of initialisers to call in root-inits
2340 # They could be setters or attributes
2342 # REQUIRE `mproperty.is_root_init == (new_msignature != null)`
2343 var initializers
= new Array[MProperty]
2345 # Is the method definition abstract?
2346 var is_abstract
: Bool = false is writable
2348 # Is the method definition intern?
2349 var is_intern
= false is writable
2351 # Is the method definition extern?
2352 var is_extern
= false is writable
2354 # An optional constant value returned in functions.
2356 # Only some specific primitife value are accepted by engines.
2357 # Is used when there is no better implementation available.
2359 # Currently used only for the implementation of the `--define`
2360 # command-line option.
2361 # SEE: module `mixin`.
2362 var constant_value
: nullable Object = null is writable
2365 # A local definition of an attribute
2369 redef type MPROPERTY: MAttribute
2370 redef type MPROPDEF: MAttributeDef
2372 # The static type of the attribute
2373 var static_mtype
: nullable MType = null is writable
2376 # A local definition of a virtual type
2377 class MVirtualTypeDef
2380 redef type MPROPERTY: MVirtualTypeProp
2381 redef type MPROPDEF: MVirtualTypeDef
2383 # The bound of the virtual type
2384 var bound
: nullable MType = null is writable
2386 # Is the bound fixed?
2387 var is_fixed
= false is writable
2394 # * `interface_kind`
2398 # Note this class is basically an enum.
2399 # FIXME: use a real enum once user-defined enums are available
2401 redef var to_s
: String
2403 # Is a constructor required?
2406 # TODO: private init because enumeration.
2408 # Can a class of kind `self` specializes a class of kine `other`?
2409 fun can_specialize
(other
: MClassKind): Bool
2411 if other
== interface_kind
then return true # everybody can specialize interfaces
2412 if self == interface_kind
or self == enum_kind
then
2413 # no other case for interfaces
2415 else if self == extern_kind
then
2416 # only compatible with themselves
2417 return self == other
2418 else if other
== enum_kind
or other
== extern_kind
then
2419 # abstract_kind and concrete_kind are incompatible
2422 # remain only abstract_kind and concrete_kind
2427 # The class kind `abstract`
2428 fun abstract_kind
: MClassKind do return once
new MClassKind("abstract class", true)
2429 # The class kind `concrete`
2430 fun concrete_kind
: MClassKind do return once
new MClassKind("class", true)
2431 # The class kind `interface`
2432 fun interface_kind
: MClassKind do return once
new MClassKind("interface", false)
2433 # The class kind `enum`
2434 fun enum_kind
: MClassKind do return once
new MClassKind("enum", false)
2435 # The class kind `extern`
2436 fun extern_kind
: MClassKind do return once
new MClassKind("extern class", false)