do
var sub = self
if sub == sup then return true
+
+ #print "1.is {sub} a {sup}? ===="
+
if anchor == null then
assert not sub.need_anchor
assert not sup.need_anchor
else
+ # First, resolve the formal types to the simplest equivalent forms in the receiver
assert sub.can_resolve_for(anchor, null, mmodule)
+ sub = sub.lookup_fixed(mmodule, anchor)
assert sup.can_resolve_for(anchor, null, mmodule)
- end
-
- # First, resolve the formal types to a common version in the receiver
- # The trick here is that fixed formal type will be associated to the bound
- # And unfixed formal types will be associated to a canonical formal type.
- if sub isa MParameterType or sub isa MVirtualType then
- assert anchor != null
- sub = sub.resolve_for(anchor.mclass.mclass_type, anchor, mmodule, false)
- end
- if sup isa MParameterType or sup isa MVirtualType then
- assert anchor != null
- sup = sup.resolve_for(anchor.mclass.mclass_type, anchor, mmodule, false)
+ sup = sup.lookup_fixed(mmodule, anchor)
end
# Does `sup` accept null or not?
end
# Now the case of direct null and nullable is over.
- # A unfixed formal type can only accept itself
- if sup isa MParameterType or sup isa MVirtualType then
- return sub == sup
- end
-
# If `sub` is a formal type, then it is accepted if its bound is accepted
- if sub isa MParameterType or sub isa MVirtualType then
+ while sub isa MParameterType or sub isa MVirtualType do
+ #print "3.is {sub} a {sup}?"
+
+ # A unfixed formal type can only accept itself
+ if sub == sup then return true
+
assert anchor != null
- sub = sub.anchor_to(mmodule, anchor)
+ sub = sub.lookup_bound(mmodule, anchor)
+
+ #print "3.is {sub} a {sup}?"
# Manage the second layer of null/nullable
if sub isa MNullableType then
return sup_accept_null
end
end
+ #print "4.is {sub} a {sup}? <- no more resolution"
assert sub isa MClassType # It is the only remaining type
+ # A unfixed formal type can only accept itself
+ if sup isa MParameterType or sup isa MVirtualType then
+ return false
+ end
+
if sup isa MNullType then
# `sup` accepts only null
return false
# ENSURE: `not self.need_anchor implies result == self`
fun resolve_for(mtype: MType, anchor: nullable MClassType, mmodule: MModule, cleanup_virtual: Bool): MType is abstract
+ # Resolve formal type to its verbatim bound.
+ # If the type is not formal, just return self
+ #
+ # The result is returned exactly as declared in the "type" property (verbatim).
+ # So it could be another formal type.
+ #
+ # In case of conflict, the method aborts.
+ fun lookup_bound(mmodule: MModule, resolved_receiver: MType): MType do return self
+
+ # Resolve the formal type to its simplest equivalent form.
+ #
+ # Formal types are either free or fixed.
+ # When it is fixed, it means that it is equivalent with a simpler type.
+ # When a formal type is free, it means that it is only equivalent with itself.
+ # This method return the most simple equivalent type of `self`.
+ #
+ # This method is mainly used for subtype test in order to sanely compare fixed.
+ #
+ # By default, return self.
+ # See the redefinitions for specific behavior in each kind of type.
+ fun lookup_fixed(mmodule: MModule, resolved_receiver: MType): MType do return self
+
# Can the type be resolved?
#
# In order to resolve open types, the formal types must make sence.
# The property associated with the type.
# Its the definitions of this property that determine the bound or the virtual type.
- var mproperty: MProperty
+ var mproperty: MVirtualTypeProp
redef fun model do return self.mproperty.intro_mclassdef.mmodule.model
- # Lookup the bound for a given resolved_receiver
- # The result may be a other virtual type (or a parameter type)
- #
- # The result is returned exactly as declared in the "type" property (verbatim).
- #
- # In case of conflict, the method aborts.
- fun lookup_bound(mmodule: MModule, resolved_receiver: MType): MType
+ redef fun lookup_bound(mmodule: MModule, resolved_receiver: MType): MType
+ do
+ return lookup_single_definition(mmodule, resolved_receiver).bound.as(not null)
+ end
+
+ private fun lookup_single_definition(mmodule: MModule, resolved_receiver: MType): MVirtualTypeDef
do
assert not resolved_receiver.need_anchor
var props = self.mproperty.lookup_definitions(mmodule, resolved_receiver)
if props.is_empty then
abort
else if props.length == 1 then
- return props.first.as(MVirtualTypeDef).bound.as(not null)
+ return props.first
end
var types = new ArraySet[MType]
+ var res = props.first
for p in props do
- types.add(p.as(MVirtualTypeDef).bound.as(not null))
+ types.add(p.bound.as(not null))
+ if not res.is_fixed then res = p
end
if types.length == 1 then
- return types.first
+ return res
end
abort
end
- # Is the virtual type fixed for a given resolved_receiver?
- fun is_fixed(mmodule: MModule, resolved_receiver: MType): Bool
+ # A VT is fixed when:
+ # * the VT is (re-)defined with the annotation `is fixed`
+ # * the VT is (indirectly) bound to an enum class (see `enum_kind`) since there is no subtype possible
+ # * the receiver is an enum class since there is no subtype possible
+ redef fun lookup_fixed(mmodule: MModule, resolved_receiver: MType): MType
do
assert not resolved_receiver.need_anchor
- var props = self.mproperty.lookup_definitions(mmodule, resolved_receiver)
- if props.is_empty then
- abort
- end
- for p in props do
- if p.as(MVirtualTypeDef).is_fixed then return true
- end
- return false
+ resolved_receiver = resolved_receiver.as_notnullable
+ assert resolved_receiver isa MClassType # It is the only remaining type
+
+ var prop = lookup_single_definition(mmodule, resolved_receiver)
+ var res = prop.bound.as(not null)
+
+ # Recursively lookup the fixed result
+ res = res.lookup_fixed(mmodule, resolved_receiver)
+
+ # 1. For a fixed VT, return the resolved bound
+ if prop.is_fixed then return res
+
+ # 2. For a enum boud, return the bound
+ if res isa MClassType and res.mclass.kind == enum_kind then return res
+
+ # 3. for a enum receiver return the bound
+ if resolved_receiver.mclass.kind == enum_kind then return res
+
+ return self
end
redef fun resolve_for(mtype, anchor, mmodule, cleanup_virtual)
do
+ if not cleanup_virtual then return self
assert can_resolve_for(mtype, anchor, mmodule)
# self is a virtual type declared (or inherited) in mtype
# The point of the function it to get the bound of the virtual type that make sense for mtype
# But because mtype is maybe a virtual/formal type, we need to get a real receiver first
#print "{class_name}: {self}/{mtype}/{anchor}?"
- var resolved_reciever
+ var resolved_receiver
if mtype.need_anchor then
assert anchor != null
- resolved_reciever = mtype.resolve_for(anchor, null, mmodule, true)
+ resolved_receiver = mtype.resolve_for(anchor, null, mmodule, true)
else
- resolved_reciever = mtype
+ resolved_receiver = mtype
end
# Now, we can get the bound
- var verbatim_bound = lookup_bound(mmodule, resolved_reciever)
+ var verbatim_bound = lookup_bound(mmodule, resolved_receiver)
# The bound is exactly as declared in the "type" property, so we must resolve it again
var res = verbatim_bound.resolve_for(mtype, anchor, mmodule, cleanup_virtual)
- #print "{class_name}: {self}/{mtype}/{anchor} -> {self}/{resolved_receiver}/{anchor} -> {verbatim_bound}/{mtype}/{anchor} -> {res}"
-
- # What to return here? There is a bunch a special cases:
- # If 'cleanup_virtual' we must return the resolved type, since we cannot return self
- if cleanup_virtual then return res
- # If the receiver is a intern class, then the virtual type cannot be redefined since there is no possible subclass. self is just fixed. so simply return the resolution
- if resolved_reciever isa MNullableType then resolved_reciever = resolved_reciever.mtype
- if resolved_reciever.as(MClassType).mclass.kind == enum_kind then return res
- # If the resolved type isa MVirtualType, it means that self was bound to it, and cannot be unbound. self is just fixed. so return the resolution.
- if res isa MVirtualType then return res
- # If we are final, just return the resolution
- if is_fixed(mmodule, resolved_reciever) then return res
- # If the resolved type isa intern class, then there is no possible valid redefinition in any potential subclass. self is just fixed. so simply return the resolution
- if res isa MClassType and res.mclass.kind == enum_kind then return res
- # TODO: What if bound to a MParameterType?
- # Note that Nullable types can always be redefined by the non nullable version, so there is no specific case on it.
- # If anything apply, then `self' cannot be resolved, so return self
- return self
+ return res
end
redef fun can_resolve_for(mtype, anchor, mmodule)
redef fun to_s do return name
- # Resolve the bound for a given resolved_receiver
- # The result may be a other virtual type (or a parameter type)
- fun lookup_bound(mmodule: MModule, resolved_receiver: MType): MType
+ redef fun lookup_bound(mmodule: MModule, resolved_receiver: MType): MType
do
assert not resolved_receiver.need_anchor
+ resolved_receiver = resolved_receiver.as_notnullable
+ assert resolved_receiver isa MClassType # It is the only remaining type
var goalclass = self.mclass
+ if resolved_receiver.mclass == goalclass then
+ return resolved_receiver.arguments[self.rank]
+ end
var supertypes = resolved_receiver.collect_mtypes(mmodule)
for t in supertypes do
if t.mclass == goalclass then
abort
end
+ # A PT is fixed when:
+ # * Its bound is a enum class (see `enum_kind`).
+ # The PT is just useless, but it is still a case.
+ # * More usually, the `resolved_receiver` is a subclass of `self.mclass`,
+ # so it is necessarily fixed in a `super` clause, either with a normal type
+ # or with another PT.
+ # See `resolve_for` for examples about related issues.
+ redef fun lookup_fixed(mmodule: MModule, resolved_receiver: MType): MType
+ do
+ assert not resolved_receiver.need_anchor
+ resolved_receiver = resolved_receiver.as_notnullable
+ assert resolved_receiver isa MClassType # It is the only remaining type
+ var res = self.resolve_for(resolved_receiver.mclass.mclass_type, resolved_receiver, mmodule, false)
+ return res
+ end
+
redef fun resolve_for(mtype, anchor, mmodule, cleanup_virtual)
do
assert can_resolve_for(mtype, anchor, mmodule)
resolved_receiver = anchor.arguments[resolved_receiver.rank]
if resolved_receiver isa MNullableType then resolved_receiver = resolved_receiver.mtype
end
- assert resolved_receiver isa MClassType
+ assert resolved_receiver isa MClassType # It is the only remaining type
# Eh! The parameter is in the current class.
# So we return the corresponding argument, no mater what!
return self.mtype.can_resolve_for(mtype, anchor, mmodule)
end
+ # Efficiently returns `mtype.lookup_fixed(mmodule, resolved_receiver).as_nullable`
+ redef fun lookup_fixed(mmodule, resolved_receiver)
+ do
+ var t = mtype.lookup_fixed(mmodule, resolved_receiver)
+ if t == mtype then return self
+ return t.as_nullable
+ end
+
redef fun depth do return self.mtype.depth
redef fun length do return self.mtype.length
nitlanguage / nit.git / blobdiff