[nit.git] / src / modelize_class.nit

# This file is part of NIT ( http://www.nitlanguage.org ).
#
# Copyright 2012 Jean Privat <jean@pryen.org>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Analysis and verification of class definitions to instantiate model element
module modelize_class

import modelbuilder

redef class ToolContext
        var modelize_class_phase: Phase = new ModelizeClassPhase(self, null)
end

private class ModelizeClassPhase
        super Phase

        redef fun process_nmodule(nmodule)
        do
                toolcontext.modelbuilder.build_classes(nmodule)
        end
end

redef class ModelBuilder
        # Visit the AST and create the `MClass` objects
        private fun build_a_mclass(nmodule: AModule, nclassdef: AClassdef)
        do
                var mmodule = nmodule.mmodule.as(not null)

                var name: String
                var nkind: nullable AClasskind
                var mkind: MClassKind
                var nvisibility: nullable AVisibility
                var mvisibility: nullable MVisibility
                var arity = 0
                if nclassdef isa AStdClassdef then
                        name = nclassdef.n_id.text
                        nkind = nclassdef.n_classkind
                        mkind = nkind.mkind
                        nvisibility = nclassdef.n_visibility
                        mvisibility = nvisibility.mvisibility
                        arity = nclassdef.n_formaldefs.length
                        if mvisibility == protected_visibility then
                                error(nvisibility, "Error: only properties can be protected.")
                                return
                        else if mvisibility == intrude_visibility then
                                error(nvisibility, "Error: intrude is not a legal visibility for classes.")
                                return
                        end
                else if nclassdef isa ATopClassdef then
                        name = "Object"
                        nkind = null
                        mkind = interface_kind
                        nvisibility = null
                        mvisibility = public_visibility
                else if nclassdef isa AMainClassdef then
                        name = "Sys"
                        nkind = null
                        mkind = concrete_kind
                        nvisibility = null
                        mvisibility = public_visibility
                else
                        abort
                end

                var mclass = try_get_mclass_by_name(nclassdef, mmodule, name)
                if mclass == null then
                        if nclassdef isa AStdClassdef and nclassdef.n_kwredef != null then
                                error(nclassdef, "Redef error: No imported class {name} to refine.")
                                return
                        end
                        mclass = new MClass(mmodule, name, arity, mkind, mvisibility)
                        #print "new class {mclass}"
                else if nclassdef isa AStdClassdef and nmodule.mclass2nclassdef.has_key(mclass) then
                        error(nclassdef, "Error: A class {name} is already defined at line {nmodule.mclass2nclassdef[mclass].location.line_start}.")
                        return
                else if nclassdef isa AStdClassdef and nclassdef.n_kwredef == null then
                        error(nclassdef, "Redef error: {name} is an imported class. Add the redef keyword to refine it.")
                        return
                else if mclass.arity != arity then
                        error(nclassdef, "Redef error: Formal parameter arity missmatch; got {arity}, expected {mclass.arity}.")
                        return
                else if nkind != null and mkind != concrete_kind and mclass.kind != mkind then
                        error(nkind, "Error: refinement changed the kind from a {mclass.kind} to a {mkind}")
                else if nvisibility != null and mvisibility != public_visibility and mclass.visibility != mvisibility then
                        error(nvisibility, "Error: refinement changed the visibility from a {mclass.visibility} to a {mvisibility}")
                end
                nclassdef.mclass = mclass
                nmodule.mclass2nclassdef[mclass] = nclassdef
        end

        # Visit the AST and create the `MClassDef` objects
        private fun build_a_mclassdef(nmodule: AModule, nclassdef: AClassdef)
        do
                var mmodule = nmodule.mmodule.as(not null)
                var objectclass = try_get_mclass_by_name(nmodule, mmodule, "Object")
                var mclass = nclassdef.mclass
                if mclass == null then return # Skip error
                #var mclassdef = nclassdef.mclassdef.as(not null)

                var names = new Array[String]
                var bounds = new Array[MType]
                if nclassdef isa AStdClassdef and mclass.arity > 0 then
                        # Collect formal parameter names
                        for i in [0..mclass.arity[ do
                                var nfd = nclassdef.n_formaldefs[i]
                                var ptname = nfd.n_id.text
                                if names.has(ptname) then
                                        error(nfd, "Error: A formal parameter type `{ptname}' already exists")
                                        return
                                end
                                for c in ptname.chars do if c >= 'a' and c<= 'z' then
                                        warning(nfd, "Warning: lowercase in the formal parameter type {ptname}")
                                        break
                                end
                                names.add(ptname)
                                nfd.mtype = mclass.mclass_type.arguments[i].as(MParameterType)
                        end

                        # Revolve bound for formal parameter names
                        for i in [0..mclass.arity[ do
                                var nfd = nclassdef.n_formaldefs[i]
                                var nfdt = nfd.n_type
                                if nfdt != null then
                                        var bound = resolve_mtype_unchecked(mmodule, null, nfdt, false)
                                        if bound == null then return # Forward error
                                        if bound.need_anchor then
                                                # No F-bounds!
                                                error(nfd, "Error: Formal parameter type `{names[i]}' bounded with a formal parameter type")
                                        else
                                                bounds.add(bound)
                                                nfd.bound = bound
                                        end
                                else if mclass.mclassdefs.is_empty then
                                        # No bound, then implicitely bound by nullable Object
                                        var bound = objectclass.mclass_type.as_nullable
                                        bounds.add(bound)
                                        nfd.bound = bound
                                else
                                        # Inherit the bound
                                        var bound = mclass.intro.bound_mtype.arguments[i]
                                        bounds.add(bound)
                                        nfd.bound = bound
                                end
                        end
                end

                var bound_mtype = mclass.get_mtype(bounds)
                var mclassdef = new MClassDef(mmodule, bound_mtype, nclassdef.location, names)
                nclassdef.mclassdef = mclassdef
                self.mclassdef2nclassdef[mclassdef] = nclassdef

                if nclassdef isa AStdClassdef then
                        var ndoc = nclassdef.n_doc
                        if ndoc != null then
                                var mdoc = ndoc.to_mdoc
                                mclassdef.mdoc = mdoc
                                mdoc.original_mentity = mclassdef
                        end
                end

                if mclassdef.is_intro then
                        self.toolcontext.info("{mclassdef} introduces new {mclass.kind} {mclass.full_name}", 3)
                else
                        self.toolcontext.info("{mclassdef} refine {mclass.kind} {mclass.full_name}", 3)
                end
        end

        # Visit the AST and set the super-types of the `MClassDef` objects
        private fun collect_a_mclassdef_inheritance(nmodule: AModule, nclassdef: AClassdef)
        do
                var mmodule = nmodule.mmodule.as(not null)
                var objectclass = try_get_mclass_by_name(nmodule, mmodule, "Object")
                var pointerclass = try_get_mclass_by_name(nmodule, mmodule, "Pointer")
                var mclass = nclassdef.mclass.as(not null)
                var mclassdef = nclassdef.mclassdef.as(not null)

                # Do we need to specify Object as a super class?
                var specobject = true

                # Do we need to specify Pointer as a super class? (is only valid
                # if `nclassdef` is an extern class)
                var specpointer = true

                var supertypes = new Array[MClassType]
                if nclassdef isa AStdClassdef then
                        for nsc in nclassdef.n_superclasses do
                                specobject = false
                                var ntype = nsc.n_type
                                var mtype = resolve_mtype_unchecked(mmodule, mclassdef, ntype, false)
                                if mtype == null then continue # Skip because of error
                                if not mtype isa MClassType then
                                        error(ntype, "Error: supertypes cannot be a formal type")
                                        return
                                end
                                if not mclass.kind.can_specialize(mtype.mclass.kind) then
                                        error(ntype, "Error: {mclass.kind} {mclass} cannot specialize {mtype.mclass.kind} {mtype.mclass}")
                                end
                                supertypes.add mtype
                                #print "new super : {mclass} < {mtype}"
                                if mtype.mclass.kind == extern_kind then specpointer = false
                        end
                end

                if mclassdef.is_intro and objectclass != null then
                        if mclass.kind == extern_kind and mclass.name != "Pointer" then
                                # it is an extern class, but not a Pointer
                                if specpointer then supertypes.add pointerclass.mclass_type
                        else if specobject and mclass.name != "Object" then
                                # it is a standard class without super class (but is not Object)
                                supertypes.add objectclass.mclass_type
                        end
                end

                mclassdef.set_supertypes(supertypes)
                if not supertypes.is_empty then self.toolcontext.info("{mclassdef} new super-types: {supertypes.join(", ")}", 3)
        end

        # Check the validity of the specialization heirarchy
        private fun check_supertypes(nmodule: AModule, nclassdef: AClassdef)
        do
                var mmodule = nmodule.mmodule.as(not null)
                var objectclass = try_get_mclass_by_name(nmodule, mmodule, "Object")
                var mclass = nclassdef.mclass.as(not null)
                var mclassdef = nclassdef.mclassdef.as(not null)

                for s in mclassdef.supertypes do
                        if s.is_subtype(mmodule, mclassdef.bound_mtype, mclassdef.bound_mtype) then
                                error(nclassdef, "Error: Inheritance loop for class {mclass} with type {s}")
                        end
                end
        end

        # Build the classes of the module `nmodule`.
        # REQUIRE: classes of imported modules are already build. (let `phase` do the job)
        private fun build_classes(nmodule: AModule)
        do
                var errcount = toolcontext.error_count
                # Force building recursively
                if nmodule.build_classes_is_done then return
                nmodule.build_classes_is_done = true
                var mmodule = nmodule.mmodule.as(not null)
                for imp in mmodule.in_importation.direct_greaters do

                        if not mmodule2nmodule.has_key(imp) then continue
                        build_classes(mmodule2nmodule[imp])
                end

                if errcount != toolcontext.error_count then return

                # Create all classes
                for nclassdef in nmodule.n_classdefs do
                        self.build_a_mclass(nmodule, nclassdef)
                end

                if errcount != toolcontext.error_count then return

                # Create all classdefs
                for nclassdef in nmodule.n_classdefs do
                        self.build_a_mclassdef(nmodule, nclassdef)
                end

                if errcount != toolcontext.error_count then return

                # Create inheritance on all classdefs
                for nclassdef in nmodule.n_classdefs do
                        self.collect_a_mclassdef_inheritance(nmodule, nclassdef)
                end

                if errcount != toolcontext.error_count then return

                # Create the mclassdef hierarchy
                for mclassdef in mmodule.mclassdefs do
                        mclassdef.add_in_hierarchy
                end

                if errcount != toolcontext.error_count then return

                # Check inheritance
                for nclassdef in nmodule.n_classdefs do
                        self.check_supertypes(nmodule, nclassdef)
                end

                if errcount != toolcontext.error_count then return

                # Check unchecked ntypes
                for nclassdef in nmodule.n_classdefs do
                        if nclassdef isa AStdClassdef then
                                var mclassdef = nclassdef.mclassdef
                                # check bound of formal parameter
                                for nfd in  nclassdef.n_formaldefs do
                                        var nfdt = nfd.n_type
                                        if nfdt != null and nfdt.mtype != null then
                                                var bound = resolve_mtype(mmodule, mclassdef, nfdt)
                                                if bound == null then return # Forward error
                                        end
                                end
                                # check declared super types
                                for nsc in nclassdef.n_superclasses do
                                        var ntype = nsc.n_type
                                        if ntype.mtype != null then
                                                var mtype = resolve_mtype(mmodule, mclassdef, ntype)
                                                if mtype == null then return # Forward error
                                        end
                                end
                        end
                end

                if errcount != toolcontext.error_count then return

                # Check clash of ancestors
                for nclassdef in nmodule.n_classdefs do
                        var mclassdef = nclassdef.mclassdef.as(not null)
                        var superclasses = new HashMap[MClass, MClassType]
                        for scd in mclassdef.in_hierarchy.greaters do
                                for st in scd.supertypes do
                                        if not superclasses.has_key(st.mclass) then
                                                superclasses[st.mclass] = st
                                        else if superclasses[st.mclass] != st then
                                                var st1 = superclasses[st.mclass].resolve_for(mclassdef.mclass.mclass_type, mclassdef.bound_mtype, mmodule, false)
                                                var st2 = st.resolve_for(mclassdef.mclass.mclass_type, mclassdef.bound_mtype, mmodule, false)
                                                if st1 != st2 then
                                                        error(nclassdef, "Error: Incompatibles ancestors for {mclassdef.mclass}: {st1}, {st2}")
                                                end
                                        end
                                end
                        end
                end

                if errcount != toolcontext.error_count then return

                # TODO: Check that the super-class is not intrusive

                # Check that the superclasses are not already known (by transitivity)
                for nclassdef in nmodule.n_classdefs do
                        if not nclassdef isa AStdClassdef then continue
                        var mclassdef = nclassdef.mclassdef.as(not null)

                        # Get the direct superclasses
                        # Since we are a mclassdef, just look at the mclassdef hierarchy
                        var parents = new Array[MClass]
                        for sup in mclassdef.in_hierarchy.direct_greaters do
                                parents.add(sup.mclass)
                        end

                        # Used to track duplicates of superclasses
                        var seen_parents = new ArrayMap[MClass, AType]

                        # The Object class
                        var objectclass = try_get_mclass_by_name(nmodule, mmodule, "Object")

                        # Check each declared superclass to see if it belong to the direct superclass
                        for nsc in nclassdef.n_superclasses do
                                var ntype = nsc.n_type
                                var mtype = ntype.mtype
                                if mtype == null then continue
                                assert mtype isa MClassType
                                var sc = mtype.mclass
                                if not parents.has(sc) or sc == objectclass then
                                        warning(ntype, "Warning: superfluous super-class {mtype} in class {mclassdef.mclass}.")
                                else if not seen_parents.has_key(sc) then
                                        seen_parents[sc] = ntype
                                else
                                        warning(ntype, "Warning: duplicated super-class {mtype} in class {mclassdef.mclass}.")
                                end
                        end
                end
        end

        # Register the nclassdef associated to each mclassdef
        # FIXME: why not refine the `MClassDef` class with a nullable attribute?
        var mclassdef2nclassdef: HashMap[MClassDef, AClassdef] = new HashMap[MClassDef, AClassdef]

        # Return the static type associated to the node `ntype`.
        # `mmodule` and `mclassdef` is the context where the call is made (used to understand formal types)
        # In case of problem, an error is displayed on `ntype` and null is returned.
        # FIXME: the name "resolve_mtype" is awful
        fun resolve_mtype_unchecked(mmodule: MModule, mclassdef: nullable MClassDef, ntype: AType, with_virtual: Bool): nullable MType
        do
                var name = ntype.n_id.text
                var res: MType

                # Check virtual type
                if mclassdef != null and with_virtual then
                        var prop = try_get_mproperty_by_name(ntype, mclassdef, name).as(nullable MVirtualTypeProp)
                        if prop != null then
                                if not ntype.n_types.is_empty then
                                        error(ntype, "Type error: formal type {name} cannot have formal parameters.")
                                end
                                res = prop.mvirtualtype
                                if ntype.n_kwnullable != null then res = res.as_nullable
                                ntype.mtype = res
                                return res
                        end
                end

                # Check parameter type
                if mclassdef != null and mclassdef.parameter_names.has(name) then
                        if not ntype.n_types.is_empty then
                                error(ntype, "Type error: formal type {name} cannot have formal parameters.")
                        end
                        for i in [0..mclassdef.parameter_names.length[ do
                                if mclassdef.parameter_names[i] == name then
                                        res = mclassdef.mclass.mclass_type.arguments[i]
                                        if ntype.n_kwnullable != null then res = res.as_nullable
                                        ntype.mtype = res
                                        return res
                                end
                        end
                        abort
                end

                # Check class
                var mclass = try_get_mclass_by_name(ntype, mmodule, name)
                if mclass != null then
                        var arity = ntype.n_types.length
                        if arity != mclass.arity then
                                if arity == 0 then
                                        error(ntype, "Type error: '{name}' is a generic class.")
                                else if mclass.arity == 0 then
                                        error(ntype, "Type error: '{name}' is not a generic class.")
                                else
                                        error(ntype, "Type error: '{name}' has {mclass.arity} parameters ({arity} are provided).")
                                end
                                return null
                        end
                        if arity == 0 then
                                res = mclass.mclass_type
                                if ntype.n_kwnullable != null then res = res.as_nullable
                                ntype.mtype = res
                                return res
                        else
                                var mtypes = new Array[MType]
                                for nt in ntype.n_types do
                                        var mt = resolve_mtype_unchecked(mmodule, mclassdef, nt, with_virtual)
                                        if mt == null then return null # Forward error
                                        mtypes.add(mt)
                                end
                                res = mclass.get_mtype(mtypes)
                                if ntype.n_kwnullable != null then res = res.as_nullable
                                ntype.mtype = res
                                return res
                        end
                end

                # If everything fail, then give up :(
                error(ntype, "Type error: class {name} not found in module {mmodule}.")
                return null
        end

        # Return the static type associated to the node `ntype`.
        # `mmodule` and `mclassdef` is the context where the call is made (used to understand formal types)
        # In case of problem, an error is displayed on `ntype` and null is returned.
        # FIXME: the name "resolve_mtype" is awful
        fun resolve_mtype(mmodule: MModule, mclassdef: nullable MClassDef, ntype: AType): nullable MType
        do
                var mtype = ntype.mtype
                if mtype == null then mtype = resolve_mtype_unchecked(mmodule, mclassdef, ntype, true)
                if mtype == null then return null # Forward error

                if ntype.checked_mtype then return mtype
                if mtype isa MGenericType then
                        var mclass = mtype.mclass
                        for i in [0..mclass.arity[ do
                                var bound = mclass.intro.bound_mtype.arguments[i]
                                var nt = ntype.n_types[i]
                                var mt = resolve_mtype(mmodule, mclassdef, nt)
                                if mt == null then return null # forward error
                                var anchor
                                if mclassdef != null then anchor = mclassdef.bound_mtype else anchor = null
                                if not mt.is_subtype(mmodule, anchor, bound) then
                                        error(nt, "Type error: expected {bound}, got {mt}")
                                        return null
                                end
                        end
                end
                ntype.checked_mtype = true
                return mtype
        end

end

redef class AModule
        # Flag that indicate if the class building is already completed
        var build_classes_is_done: Bool = false
        # What is the AClassdef associated to a `MClass`?
        # Used to check multiple definition of a class.
        var mclass2nclassdef: Map[MClass, AClassdef] = new HashMap[MClass, AClassdef]
end

redef class AClassdef
        # The associated MClass once build by a `ModelBuilder`
        var mclass: nullable MClass
        # The associated MClassDef once build by a `ModelBuilder`
        var mclassdef: nullable MClassDef
end

redef class AClasskind
        # The class kind associated with the AST node class
        private fun mkind: MClassKind is abstract
end
redef class AConcreteClasskind
        redef fun mkind do return concrete_kind
end
redef class AAbstractClasskind
        redef fun mkind do return abstract_kind
end
redef class AInterfaceClasskind
        redef fun mkind do return interface_kind
end
redef class AEnumClasskind
        redef fun mkind do return enum_kind
end
redef class AExternClasskind
        redef fun mkind do return extern_kind
end

redef class AFormaldef
        # The associated parameter type
        var mtype: nullable MParameterType = null

        # The associated bound
        var bound: nullable MType = null
end

redef class AType
        # The mtype associated to the node
        var mtype: nullable MType = null

        # Is the mtype a valid one?
        var checked_mtype: Bool = false
end