Merge: Astbuilder improvement

[nit.git] / src / astbuilder.nit

# This file is part of NIT ( http://www.nitlanguage.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.

# Instantiation and transformation of semantic nodes in the AST of expressions and statements
module astbuilder

intrude import semantize::typing
intrude import literal
intrude import parser
intrude import semantize::scope
intrude import modelbuilder_base
intrude import modelize_property

# General factory to build semantic nodes in the AST of expressions
class ASTBuilder
        # The module used as reference for the building
        # It is used to gather types and other stuff
        var mmodule: MModule

        # The anchor used for some mechanism relying on types
        var anchor: nullable MClassType

        # Check mmodule to avoid a new instantiation of ASTBuilder
        fun check_mmodule(mmodule: MModule)
        do
                if self.mmodule != mmodule then self.mmodule = mmodule
        end

        # Make a new Int literal
        fun make_int(value: Int): AIntegerExpr
        do
                return new AIntegerExpr.make(value, mmodule.int_type)
        end

        # Make a new instantiation
        fun make_new(callsite: CallSite, args: nullable Array[AExpr]): ANewExpr
        do
                return new ANewExpr.make(callsite, args)
        end

        # Make a new message send
        fun make_call(recv: AExpr, callsite: CallSite, args: nullable Array[AExpr]): ACallExpr
        do
                return new ACallExpr.make(recv, callsite, args)
        end

        # Make a new, empty, sequence of statements
        fun make_block: ABlockExpr
        do
                return new ABlockExpr.make
        end

        # Make a new, empty, loop of statements
        fun make_loop: ALoopExpr
        do
                return new ALoopExpr.make
        end

        # Make a new variable read
        fun make_var_read(variable: Variable, mtype: MType): AVarExpr
        do
                return new AVarExpr.make(variable, mtype)
        end

        # Make a new variable assignment
        fun make_var_assign(variable: Variable, value: AExpr): AVarAssignExpr
        do
                return new AVarAssignExpr.make(variable, value)
        end

        # Make a new attribute read
        fun make_attr_read(recv: AExpr, attribute: MAttribute): AAttrExpr
        do
                var mtype = attribute.intro.static_mtype.resolve_for(recv.mtype.as(not null), anchor, mmodule, true)
                return new AAttrExpr.make(recv, attribute, mtype)
        end

        # Make a new attribute assignment
        fun make_attr_assign(recv: AExpr, attribute: MAttribute, value: AExpr): AAttrAssignExpr
        do
                return new AAttrAssignExpr.make(recv, attribute, value)
        end

        # Make a new escapable block
        fun make_do: ADoExpr
        do
                return new ADoExpr.make
        end

        # Make a new break for a given escapemark
        fun make_break(escapemark: EscapeMark): ABreakExpr
        do
                return new ABreakExpr.make(escapemark)
        end

        # Make a new conditional
        # `mtype` is the return type of the whole if, in case of a ternary operator.
        fun make_if(condition: AExpr, mtype: nullable MType): AIfExpr
        do
                return new AIfExpr.make(condition, mtype)
        end

        # Make a new assert
        fun make_assert(n_id : nullable TId , n_expr : AExpr , n_else : nullable AExpr): AAssertExpr
        do
                return new AAssertExpr.make(n_id , n_expr , n_else)
        end

        # Make a new method
        fun make_method(n_visibility: nullable AVisibility,
                                        tk_redef: nullable TKwredef,
                                        mmethoddef: nullable MMethodDef,
                                        n_signature: nullable ASignature,
                                        n_annotations: nullable AAnnotations,
                                        n_extern_calls: nullable AExternCalls,
                                        n_extern_code_block: nullable AExternCodeBlock,
                                        n_block: nullable AExpr): AMethPropdef
        do
                return new AMethPropdef.make(n_visibility, tk_redef, mmethoddef, n_signature, n_annotations, n_extern_calls, n_extern_code_block, n_block)
        end

        # Make a new or with two expr
        fun make_or(right_expr: AExpr, left_expr: AExpr): AOrExpr
        do
                return new AOrExpr.make(right_expr,left_expr)
        end

        # Make a new and with two expr
        fun make_and(right_expr: AExpr, left_expr: AExpr): AAndExpr
        do
                return new AAndExpr.make(right_expr,left_expr)
        end

        # Make a new parenthesis expr
        fun make_parenthesis(expr: AExpr, annotations: nullable AAnnotations): AParExpr
        do
                return new AParExpr.make(expr,annotations)
        end

        # Make a new message super
        fun make_super_call(args: nullable Array[AExpr], n_qualified: nullable AQualified): ASuperExpr
        do
                return new ASuperExpr.make(args,n_qualified)
        end

        # Make a new return
        fun make_return(expr: nullable AExpr): AReturnExpr
        do
                return new AReturnExpr.make(expr)
        end

        # Make a new not
        fun make_not(expr: AExpr): ANotExpr
        do
                return new ANotExpr.make(expr)
        end

        # Make a new attribute
        fun make_attribute(name: String,
                                        n_type: nullable AType,
                                        n_visibility: nullable AVisibility,
                                        initial_value: nullable AExpr,
                                        n_block: nullable AExpr,
                                        m_attributedef: nullable MAttributeDef,
                                        m_setterdef: nullable MMethodDef,
                                        m_getterdef: nullable MMethodDef): AAttrPropdef
        do
                return new AAttrPropdef.make(name, n_type, n_visibility, initial_value, n_block, m_attributedef, m_setterdef, m_getterdef)
        end

        # Make a new class (AStdClassdef)
        fun make_class(mclassdef: nullable MClassDef,
                                        n_visibility: nullable AVisibility,
                                        n_formaldefs : Collection[AFormaldef],
                                        n_extern_code_block : nullable AExternCodeBlock,
                                        n_propdefs : Collection[APropdef],
                                        n_classkind: nullable AClasskind): AStdClassdef
        do
                return new AStdClassdef.make(mclassdef, n_visibility, n_formaldefs, n_extern_code_block, n_propdefs, n_classkind)
        end

        fun make_var(variable: Variable, mtype: MType): AVarExpr
        do
                return new AVarExpr.make(variable, mtype)
        end

        # Make a call assignment i.e `a = 10`
        fun make_call_assign(recv: AExpr, callsite: CallSite, n_args: nullable Collection[AExpr], n_value: AExpr): ACallAssignExpr
        do
                return new ACallAssignExpr.make(recv, callsite, n_args, n_value)
        end

        # Build a callsite to call the `mproperty` in the current method `caller_method`.
        # `is_self_call` indicate if the method caller is a property of `self`
        fun create_callsite(modelbuilder: ModelBuilder, caller_property: APropdef, mproperty: MMethod, is_self_call: Bool): CallSite
        do
                # FIXME It's not the better solution to call `TypeVisitor` here to build a model entity, but some make need to have a callsite
                var type_visitor = new TypeVisitor(modelbuilder, caller_property.mpropdef.as(not null))
                var callsite = type_visitor.build_callsite_by_property(caller_property, mproperty.intro_mclassdef.bound_mtype, mproperty, is_self_call)
                assert callsite != null
                return callsite
        end
end

redef class AExpr
        # Return a new variable read that contains the value of the expression
        # This method take care efficiently of creating and initalising an anonymous local variable
        #
        # Note: since this method do side-effects (AST replacement), there could be unexpected effects when used as
        # argument of other methods related to AST transformations.
        fun make_var_read: AVarExpr
        do
                var variable = self.variable_cache
                if variable == null then
                        assert parent != null
                        var place = detach_with_placeholder
                        variable = new Variable("")
                        variable.declared_type = self.mtype
                        var nvar = new AVarAssignExpr.make(variable, self)
                        place.replace_with(nvar)
                        self.variable_cache = variable
                end
                return new AVarExpr.make(variable, variable.declared_type.as(not null))
        end

        private var variable_cache: nullable Variable

        # The `detach` method completely remove the node in the parent.
        # However, sometime, it is useful to keep the emplacement of the removed child.
        #
        # The standard use case is the insertion of a node between a parent `p` and a child `p.c`.
        # To create the new node `n`, we need to attach the child to it.
        # But, to put `n` where `c` was in `p`, the place has to be remembered.
        #
        # ~~~nitish
        # var p: AExpr
        # var c = p.c
        # var h = c.detach_with_placeholder
        # var n = astbuilder.make_XXX(c)
        # h.replace_with(n)
        # ~~~
        fun detach_with_placeholder: AExpr
        do
                var h = new APlaceholderExpr.make
                self.replace_with(h)
                return h
        end


        # Add `expr` at the end of the block
        #
        # REQUIRE: self isa ABlockExpr
        #
        # Note: this method, aimed to `ABlockExpr` is promoted to `AExpr` because of the limitations of the hierarchies generated by sablecc3
        fun add(expr: AExpr)
        do
                print "add not implemented in {inspect}"
                abort
        end

        redef fun accept_ast_validation(v)
        do
                super
                if mtype == null and not is_typed then
                        #debug "TYPING: untyped expression"
                end
        end
end

# A placeholder for a `AExpr` node
# Instances are transiantly used to mark some specific emplacements in the AST
# during complex transformations.
#
# Their must not appear in a valid AST
#
# @see AExpr::detach_with_placeholder
class APlaceholderExpr
        super AExpr
        private init make
        do
        end

        redef fun accept_ast_validation(v)
        do
                super
                debug "PARENT: remaining placeholder"
        end
end

redef class ACallAssignExpr
        private init make(recv: AExpr, callsite: CallSite, args: nullable Collection[AExpr], n_value: AExpr)
        do
                _callsite = callsite
                _mtype = callsite.recv
                _is_typed = true
                var n_args = new AListExprs
                if args != null then
                        n_args.n_exprs.add_all(args)
                end
                var n_qid = new AQid
                n_qid.n_id = new TId
                n_qid.n_id.text = callsite.mproperty.name
                init_acallassignexpr(recv, n_qid, n_args, new TAssign, n_value)
        end
end

redef class AStdClassdef
        private init make(mclassdef: nullable MClassDef,
                                        n_visibility: nullable AVisibility,
                                        n_formaldefs : Collection[Object],
                                        n_extern_code_block : nullable AExternCodeBlock,
                                        n_propdefs : Collection[Object],
                                        n_classkind: nullable AClasskind)
        do
                if n_visibility == null then n_visibility = new APublicVisibility
                if n_classkind == null then n_classkind = new AConcreteClasskind.init_aconcreteclasskind(new TKwclass)
                var n_qid = new AQclassid.init_aqclassid(null, new TClassid)
                init_astdclassdef(null, null, n_visibility, n_classkind, n_qid, null, n_formaldefs, null, n_extern_code_block, n_propdefs, new TKwend)
                _mclassdef = mclassdef
                _mclass = mclassdef.mclass
        end
end

redef class AAttrPropdef

        # Create a new `AAttrPropdef`
        # Note: By default if the `AVisibility` is not given the visibility is set to public
        private init make(name: String,
                                        n_type: nullable AType,
                                        n_visibility: nullable AVisibility,
                                        initial_value: nullable AExpr,
                                        n_block: nullable AExpr,
                                        m_attributedef: nullable MAttributeDef,
                                        m_setterdef: nullable MMethodDef,
                                        m_getterdef: nullable MMethodDef)
        do
                # Set the model type
                if n_type != null then mtype = n_type.mtype
                # Define the visibility default is public
                if n_visibility == null then n_visibility = new APublicVisibility
                init_aattrpropdef(null, null, n_visibility, new TKwvar, new TId, n_type, null, initial_value, null, null , n_block, null)
                # Set the name of the attribute
                _n_id2.text = name
                _mpropdef = m_attributedef
                _mreadpropdef = m_getterdef
                _mwritepropdef = m_setterdef
                if initial_value != null or n_block != null then has_value = true
                if m_attributedef != null then self.location = m_attributedef.location
        end
end

redef class ANotExpr
        private init make(expr: AExpr)
        do
                self.init_anotexpr(new TKwnot, expr)
        end
end

redef class AReturnExpr
        private init make(expr: nullable AExpr)
        do
                self.init_areturnexpr(null, expr)
        end
end

redef class ASuperExpr
        private init make(args: nullable Array[AExpr], n_qualified: nullable AQualified, mpropdef: nullable MMethodDef)
        do
                var n_args = new AListExprs
                if args != null then
                        n_args.n_exprs.add_all(args)
                end
                _mpropdef = mpropdef
                self.init_asuperexpr(n_qualified, new TKwsuper, n_args)
        end
end

redef class AOrExpr
        private init make(right_expr: AExpr, left_expr: AExpr)
        do
                self.init_aorexpr(right_expr,new TKwor,left_expr)
        end
end

redef class AAndExpr
        private init make(right_expr: AExpr, left_expr: AExpr)
        do
                self.init_aandexpr(right_expr,new TKwand ,left_expr)
        end
end

redef class AMethPropdef
        private init make(n_visibility: nullable AVisibility,
                                        tk_redef: nullable TKwredef,
                                        mmethoddef: nullable MMethodDef,
                                        n_signature: nullable ASignature,
                                        n_annotations: nullable AAnnotations,
                                        n_extern_calls: nullable AExternCalls,
                                        n_extern_code_block: nullable AExternCodeBlock,
                                        n_block: nullable AExpr)
        do
                var n_tid = new TId
                var n_methid = new AIdMethid.init_aidmethid(n_tid)
                if n_signature == null then n_signature = new ASignature
                if n_visibility == null then n_visibility = new APublicVisibility
                self.init_amethpropdef(null,tk_redef,n_visibility,new TKwmeth,null,null,null,n_methid,n_signature,n_annotations,n_extern_calls,n_extern_code_block,new TKwdo,n_block,new TKwend)
                self.mpropdef = mmethoddef
                if mpropdef != null then self.location = mmethoddef.location
        end

        # Execute all method verification scope flow and typing.
        # It also execute an ast validation to define all parents and all locations
        fun do_all(toolcontext: ToolContext)
        do
                self.validate
                # FIXME: The `do_` usage it is maybe to much (verification...). Solution: Cut the `do_` methods into simpler parts
                self.do_scope(toolcontext)
                self.do_flow(toolcontext)
                self.do_typing(toolcontext.modelbuilder)
        end
end

redef class AAssertExpr
        private init make(n_id : nullable TId , n_expr : nullable AExpr , n_else : nullable AExpr)
        do
                n_kwassert = new TKwassert
                n_kwelse = null
                if n_else != null then n_kwelse = new TKwelse
                self.init_aassertexpr(n_kwassert, n_id , n_expr , n_kwelse , n_else)
        end
end

redef class ALoopExpr
        private init make
        do
                _n_kwloop = new TKwloop
                self.is_typed = true
                n_block = new ABlockExpr
                n_block.is_typed = true
        end

        redef fun add(expr)
        do
                n_block.add expr
        end
end

redef class ADoExpr
        private init make
        do
                _n_kwdo = new TKwdo
                self.is_typed = true
                n_block = new ABlockExpr
                n_block.is_typed = true
        end

        # Make a new break expression of the given do
        fun make_break: ABreakExpr
        do
                var escapemark = self.break_mark
                if escapemark == null then
                        escapemark = new EscapeMark(null)
                        self.break_mark = escapemark
                end
                return new ABreakExpr.make(escapemark)
        end

        redef fun add(expr)
        do
                n_block.add expr
        end
end

redef class ABreakExpr
        private init make(escapemark: EscapeMark)
        do
                _n_kwbreak = new TKwbreak
                self.escapemark = escapemark
                escapemark.escapes.add self
                self.is_typed = true
        end
end

redef class AIfExpr
        private init make(condition: AExpr, mtype: nullable MType)
        do
                _n_kwif = new TKwif
                _n_expr = condition
                _n_expr.parent = self
                _n_kwthen = new TKwthen
                _n_then = new ABlockExpr.make
                _n_kwelse = new TKwelse
                _n_else = new ABlockExpr.make
                self.mtype = mtype
                if mtype != null then self.is_typed = true
        end
end

redef class AType

        private init make(t: nullable MType)
        do
                var n_id = new TClassid
                var n_qid = new AQclassid
                n_qid.n_id = n_id
                _n_qid = n_qid
                _mtype = t
        end

        redef fun clone: SELF
        do
                return new AType.make(mtype)
        end
end

# Primitive type

redef class AIntegerExpr

        private init make(value: nullable Numeric, t: nullable MType)
        do
                _mtype = t
                if t != null then self.is_typed = true
                _value = value
                _n_integer = new TInteger # dummy
        end

        redef fun clone: SELF
        do
                return new AIntegerExpr.make(value, mtype)
        end
end

redef class AFloatExpr

        private init make(value: nullable Float, t: nullable MType)
        do
                _mtype = t
                if t != null then self.is_typed = true
                _value = value
                _n_float = new TFloat # dummy
        end

        redef fun clone: SELF
        do
                return new AFloatExpr.make(value, mtype)
        end
end

redef class ATrueExpr

        private init make(t: nullable MType)
        do
                init_atrueexpr(new TKwtrue, null)
                _mtype = t
                if t != null then self.is_typed = true
        end

        redef fun clone: SELF
        do
                return new ATrueExpr.make(mtype)
        end
end

redef class AFalseExpr

        private init make(t: nullable MType)
        do
                init_afalseexpr(new TKwfalse, null)
                _mtype = t
                if t != null then self.is_typed = true
        end

        redef fun clone: SELF
        do
                return new AFalseExpr.make(mtype)
        end
end

redef class ACharExpr

        # `token_text` represent the real value as it's present in a file not only the char.
        # `token_text` is needed if you want to use some methods (for exemple: `prefix`, `suffix` or `is_code_point methods`)
        private init make(value: nullable Char, t: nullable MType, token_text: nullable String)
        do
                _value = value
                _mtype = t
                _n_char = new TChar
                if token_text != null then n_char.text = token_text
                if t != null then self.is_typed = true
        end

        redef fun clone: SELF
        do
                var self_clone = new ACharExpr.make(self.value, mtype, n_char.text)
                return self_clone
        end
end

redef class ANewExpr
        private init make(callsite: CallSite, args: nullable Array[AExpr])
        do
                _n_kwnew = new TKwnew
                _n_type = new AType.make
                _n_args = new AListExprs
                if args != null then
                        n_args.n_exprs.add_all(args)
                end
                self.callsite = callsite
                self.recvtype = callsite.recv.as(MClassType)
                if callsite.mproperty.is_new then
                        self.mtype = callsite.msignature.return_mtype
                else
                        self.mtype = callsite.recv
                end
                self.is_typed = true
        end
end

redef class ACallExpr
        private init make(recv: AExpr, callsite: nullable CallSite, args: nullable Array[AExpr])
        do
                self._n_expr = recv
                _n_args = new AListExprs
                _n_qid = new AQid
                _n_qid.n_id = new TId
                _n_qid.n_id.text = callsite.mproperty.name
                if args != null then
                        self.n_args.n_exprs.add_all(args)
                end

                if callsite != null then
                        self.callsite = callsite
                        self.mtype = callsite.msignature.return_mtype
                        self.is_typed = true
                end
        end
end

redef class AAsNotnullExpr
        private init make(n_expr: AExpr, t: nullable MType)
        do
                init_aasnotnullexpr(n_expr, new TKwas, null, new TKwnot, new TKwnull, null)
                _mtype = t
                if t != null then _is_typed = true
        end
end

redef class ANullExpr

        private init make(t: nullable MType)
        do
                init_anullexpr(new TKwnull, null)
                _mtype = t
                if t != null then self.is_typed = true
        end
end

redef class ASelfExpr

        private init make(v: nullable Variable, t: nullable MType)
        do
                init_aselfexpr(new TKwself, null)
                _mtype = t
                if t != null then is_typed =true
        end

        redef fun clone: SELF
        do
                return new ASelfExpr.make(self.variable, self.mtype)
        end
end

redef class AImplicitSelfExpr

        redef fun clone: SELF
        do
                var self_clone = new AImplicitSelfExpr.make(variable, mtype)
                self_clone.is_sys = is_sys
                return self_clone
        end
end


redef class AAttrExpr
        private init make(recv: AExpr, attribute: nullable MAttribute, t: nullable MType)
        do
                _n_expr = recv
                recv.parent = self
                _n_id = new TAttrid
                _mproperty = attribute
                _mtype = t
                if t != null then _is_typed = true
        end
end

redef class AAttrAssignExpr
        private init make(recv: AExpr, attribute: nullable MAttribute, value: AExpr)
        do
                _n_expr = recv
                recv.parent = self
                _n_id = new TAttrid
                _n_value = value
                value.parent = self
                _n_assign = new TAssign
                _mproperty = attribute
                _mtype = value.mtype
        end
end

redef class AVarExpr
        private init make(v: nullable Variable, t: nullable MType)
        do
                _n_id = new TId
                if v != null then _n_id.text = v.name
                _variable = v
                _mtype = t
                if t != null then is_typed = true
        end
end

redef class AVarAssignExpr
        private init make(v: nullable Variable, value: AExpr)
        do
                _n_id = new TId
                if v != null then _n_id.text = v.name
                _n_value = value
                value.parent = self
                _n_assign = new TAssign
                _variable = v
                _mtype = value.mtype
                if _mtype != null then _is_typed = true
        end
end

redef class ASignature

        init make_from_msignature(msignature: MSignature)
        do
                var nparams = new Array[AParam]
                for mparam in msignature.mparameters do
                        var variable = new Variable(mparam.name)
                        variable.declared_type = mparam.mtype
                        n_params.add(new AParam.make(variable, new AType.make(mparam.mtype)))
                end
                var return_type = null
                if msignature.return_mtype != null then return_type = new AType.make(msignature.return_mtype)
                init_asignature(null, nparams, null, return_type)
        end

        redef fun clone: SELF
        do
                var ntype = n_type
                if ntype != null then ntype = n_type.clone
                return new ASignature.init_asignature(null, n_params.clone, null, ntype)
        end
end

redef class AParam

        private init make(v: nullable Variable, t: nullable AType)
        do
                _n_id = new TId
                if v != null then _n_id.text = v.name
                _variable = v
                _n_type = t
        end

        redef fun clone: SELF
        do
                var ntype = n_type
                if ntype != null then ntype = n_type.clone
                return new AParam.make(variable, ntype)
        end
end

redef class AFormaldef

        private init make(mparameter: MParameterType, t: AType)
        do
                _n_id = new TClassid
                _n_id.text = mparameter.name
                _n_type = t
                _mtype = mparameter
        end
end

redef class ABlockExpr
        private init make(t: nullable MType)
        do
                if t != null then
                        _mtype = t
                        _is_typed = true
                end
        end

        redef fun add(expr)
        do
                n_expr.add expr
                expr.parent = self
        end

        fun add_all(exprs: Array[AExpr])
        do
                for expr in exprs do
                        add(expr)
                end
        end

        redef fun clone: SELF
        do
                var clone = new ABlockExpr.make(mtype)
                for expr in self.n_expr do
                        clone.add(expr.clone)
                end
                return clone
        end
end

redef class AQclassid
        redef fun clone: SELF
        do
                return new AQclassid.init_aqclassid(n_qualified.clone, n_id)
        end
end

redef class AQualified
        redef fun clone: SELF
        do
                return new AQualified.init_aqualified(n_id.clone, n_classid)
        end
end

redef class AQid
        redef fun clone: SELF
        do
                var clone_n_qualified = n_qualified
                if n_qualified != null then clone_n_qualified = n_qualified.clone
                return new AQid.init_aqid(clone_n_qualified, n_id.clone)
        end
end

redef class TId
        redef fun clone: SELF
        do
                return new TId.init_tk(location)
        end
end

redef class AParExpr
        private init make(expr: AExpr, annotations: nullable AAnnotations)
        do
                self.init_aparexpr(new TOpar, expr, new TCpar, annotations)
        end
end

# Check the consitency of AST
class ASTValidationVisitor
        super Visitor
        redef fun visit(node)
        do
                node.accept_ast_validation(self)
        end
        private var path = new CircularArray[ANode]
        private var seen = new HashSet[ANode]
end

redef class ANodes
        super Cloneable

        redef fun clone: SELF
        do
                var clone_anodes = new ANodes[E](self.parent)
                for node in self do
                        clone_anodes.add(node.clone)
                end
                return clone_anodes
        end
end

redef class ANode
        super Cloneable

        redef fun clone: SELF
        do
                # By default the clone abort to avoid surprises
                print "The clone method is not implemented for the `{self.class_name}` class"
                abort
        end
        # Recursively validate a AST node.
        # This ensure that location and parenting are defined and coherent.
        #
        # After complex low-level AST manipulation and construction,
        # it is recommended to call it.
        #
        # Note: this just instantiate and run an `ASTValidationVisitor`.
        fun validate
        do
                (new ASTValidationVisitor).enter_visit(self)
        end

        private fun accept_ast_validation(v: ASTValidationVisitor)
        do
                var parent = self.parent
                var path = v.path

                if path.length > 0 then
                        var path_parent = v.path.first
                        if parent == null then
                                self.parent = path_parent
                                #debug "PARENT: expected parent: {path_parent}"
                                v.seen.add(self)
                        else if parent != path_parent then
                                self.parent = path_parent
                                if v.seen.has(self) then
                                        debug "DUPLICATE (NOTATREE): already seen node with parent {parent} now with {path_parent}."
                                else
                                        v.seen.add(self)
                                        debug "PARENT: expected parent: {path_parent}, got {parent}"
                                end
                        end
                end

                if not isset _location then
                        #debug "LOCATION: unlocated node {v.path.join(", ")}"
                        _location = self.parent.location
                end

                path.unshift(self)
                visit_all(v)
                path.shift
        end
end

redef class AAnnotation

        redef fun accept_ast_validation(v)
        do
                # Do not enter in annotations
        end

        private init make(n_args : ANodes[AExpr])
        do
                _n_visibility = new APublicVisibility
                _n_args = n_args
        end
end

redef class MEntity
        # Build a ANode from `self`
        #
        # Allows the creation of an AST node from a model entity.
        fun create_ast_representation(astbuilder: nullable ASTBuilder): ANode is abstract
end

redef class MPropDef
        redef fun create_ast_representation(astbuilder: nullable ASTBuilder): APropdef is abstract
end

redef class MClassDef
        redef fun create_ast_representation(astbuilder: nullable ASTBuilder): AStdClassdef do
                if astbuilder == null then astbuilder = new ASTBuilder(mmodule)
                var n_propdefs = new Array[APropdef]
                for mpropdef in self.mpropdefs do
                        n_propdefs.add(mpropdef.create_ast_representation(astbuilder))
                end
                var n_formaldefs = new Array[AFormaldef]
                for mparameter in self.mclass.mparameters do n_formaldefs.add(mparameter.create_ast_representation(astbuilder))

                return astbuilder.make_class(self, visibility.create_ast_representation(astbuilder), n_formaldefs, null, n_propdefs, null)
        end
end

redef class MAttributeDef
        redef fun create_ast_representation(astbuilder: nullable ASTBuilder): AAttrPropdef do
                if astbuilder == null then astbuilder = new ASTBuilder(mclassdef.mmodule)
                var ntype = null
                if self.static_mtype != null then ntype = static_mtype.create_ast_representation(astbuilder)
                return astbuilder.make_attribute("_" + self.name, ntype, self.visibility.create_ast_representation(astbuilder), null, null, self, null, null)
        end
end

redef class MMethodDef
        redef fun create_ast_representation(astbuilder: nullable ASTBuilder): AMethPropdef do
                if astbuilder == null then astbuilder = new ASTBuilder(mclassdef.mmodule)
                var tk_redef = null
                if self.mproperty.intro != self then tk_redef = new TKwredef
                var  n_signature = if self.msignature == null then new ASignature else self.msignature.create_ast_representation(astbuilder)
                return astbuilder.make_method(visibility.create_ast_representation(astbuilder), tk_redef, self, n_signature)
        end
end

redef class MVisibility
        fun create_ast_representation(astbuilder: nullable ASTBuilder): AVisibility do
                if self.to_s == "public" then
                        return new APublicVisibility
                else if self.to_s == "private" then
                        return new APrivateVisibility
                else if self.to_s == "protected" then
                        return new AProtectedVisibility
                else
                        return new AIntrudeVisibility
                end
        end
end

redef class MSignature
        redef fun create_ast_representation(astbuilder: nullable ASTBuilder): ASignature do
                var nparams = new Array[AParam]
                for mparam in mparameters do nparams.add(mparam.create_ast_representation(astbuilder))
                var return_type = null
                if self.return_mtype != null then return_type = self.return_mtype.create_ast_representation(astbuilder)
                return new ASignature.init_asignature(null, nparams, null, return_type)
        end
end

redef class MParameter
        redef fun create_ast_representation(astbuilder: nullable ASTBuilder): AParam do
                var variable = new Variable(self.name)
                variable.declared_type = self.mtype
                return new AParam.make(variable, self.mtype.create_ast_representation(astbuilder))
        end
end

redef class MParameterType
        redef fun create_ast_representation(astbuilder: nullable ASTBuilder): AFormaldef do
                var n_type = super
                return new AFormaldef.make(self, n_type)
        end
end

redef class MType
        redef fun create_ast_representation(astbuilder: nullable ASTBuilder): AType do
                return new AType.make(self)
        end
end

redef class ModelBuilder
        # Try to get MMethod property if exist in the given mclassdef. return new `MMethod` if not exist.
        private fun get_mmethod(name: String, mclassdef: MClassDef, visibility: nullable MVisibility): MMethod do
                visibility = visibility or else public_visibility
                var mproperty = try_get_mproperty_by_name(null, mclassdef, name).as(nullable MMethod)
                if mproperty == null then mproperty = new MMethod(mclassdef, name, mclassdef.location, visibility)
                return mproperty
        end

        # Creation of a new method (AST and model representation) with the given name.
        # See `create_method_from_property` for more information.
        fun create_method_from_name(name: String, mclassdef: MClassDef, is_abstract: Bool, msignature: nullable MSignature, visibility: nullable MVisibility): AMethPropdef do
                var mproperty = get_mmethod(name, mclassdef, visibility)
                return create_method_from_property(mproperty, mclassdef, is_abstract, msignature)
        end

        # Creation of a new method (AST and model representation) with the given MMethod.
        # Take care, if `is_abstract == false` the AMethPropdef returned has an empty body (potential error if the given signature has an return type).
        fun create_method_from_property(mproperty: MMethod,  mclassdef: MClassDef, is_abstract: Bool, msignature: nullable MSignature): AMethPropdef do
                var m_def = new MMethodDef(mclassdef, mproperty, mclassdef.location)

                if msignature == null then msignature = new MSignature(new Array[MParameter])

                m_def.msignature = msignature
                m_def.is_abstract = true
                var n_def = m_def.create_ast_representation
                # Association new npropdef to mpropdef
                unsafe_add_mpropdef2npropdef(m_def,n_def)

                if not is_abstract then
                        n_def.mpropdef.is_abstract = false
                        n_def.n_block = new ABlockExpr.make
                end

                return n_def
        end

        # Creation of a new attribute (AST and model representation) with the given name.
        # See `create_attribute_from_property` for more information.
        fun create_attribute_from_name(name: String, mclassdef: MClassDef, mtype: MType, visibility: nullable MVisibility): AAttrPropdef do
                if visibility == null then visibility = public_visibility
                var mattribute = try_get_mproperty_by_name(null, mclassdef, name)
                if mattribute == null then mattribute = new MAttribute(mclassdef, name, mclassdef.location, visibility)
                return create_attribute_from_property(mattribute.as(MAttribute), mclassdef, mtype)
        end

        # Creation of a new attribute (AST and model representation) with the given MAttribute.
        # See `create_attribute_from_propdef` for more information.
        fun create_attribute_from_property(mattribute: MAttribute, mclassdef: MClassDef, mtype: MType): AAttrPropdef do
                var attribut_def = new MAttributeDef(mclassdef, mattribute, mclassdef.location)
                attribut_def.static_mtype = mtype
                return create_attribute_from_propdef(attribut_def)
        end

        # Creation of a new attribute (AST representation) with the given MAttributeDef.
        fun create_attribute_from_propdef(mattribut_def: MAttributeDef): AAttrPropdef
        is
                expect(mclassdef2node(mattribut_def.mclassdef) != null)
        do
                var n_attribute = mattribut_def.create_ast_representation

                var nclass = mclassdef2node(mattribut_def.mclassdef)

                n_attribute.location = mattribut_def.location
                n_attribute.validate

                nclass.n_propdefs.unsafe_add_all([n_attribute])
                nclass.validate

                n_attribute.build_read_property(self, mattribut_def.mclassdef)
                n_attribute.build_read_signature

                mpropdef2npropdef[mattribut_def] = n_attribute
                return n_attribute
        end

        # Creation of a new class (AST and model representation) with the given name.
        # `visibility` : Define the visibility of the method. If it's `null` the default is `public_visibility`
        # See `create_class_from_mclass` for more information.
        fun create_class_from_name(name: String, super_type: Array[MClassType], mmodule: MModule, visibility: nullable MVisibility): AStdClassdef do
                if visibility == null then visibility = public_visibility
                var mclass = try_get_mclass_by_name(null, mmodule, name)
                if mclass == null then mclass = new MClass(mmodule, name, mmodule.location, new Array[String], concrete_kind, visibility)
                return create_class_from_mclass(mclass, super_type, mmodule)
        end

        # Creation of a new class (AST and model representation) with the given MClass.
        # This method creates a new concrete class definition `MClassDef`, and adds it to the class hierarchy.
        # See `create_class_from_mclassdef` for more information.
        fun create_class_from_mclass(mclass: MClass, super_type: Array[MClassType], mmodule: MModule): AStdClassdef do
                var mclassdef = new MClassDef(mmodule, mclass.mclass_type, mmodule.location)
                mclassdef.set_supertypes(super_type)
                mclassdef.add_in_hierarchy

                return create_class_from_mclassdef(mclassdef, mmodule)
        end

        # Creation of a new class (AST representation) with the given MClassDef.
        # Note all the properties of our MClassDef will also generate an AST representation.
        # Make an error if the attribute already has a representation in the modelbuilder.
        # This method also create the default constructor.
        fun create_class_from_mclassdef(mclassdef: MClassDef, mmodule: MModule): AStdClassdef do
                var n_classdef = mclassdef.create_ast_representation
                n_classdef.location = mclassdef.location
                n_classdef.validate

                for n_propdef in n_classdef.n_propdefs do
                        var mpropdef = n_propdef.mpropdef
                        assert mpropdef != null

                        var p_npropdef = mpropdef2node(mpropdef)
                        if  p_npropdef != null then error(null, "The property `{mpropdef.name}` already has a representation in the AST.")
                        unsafe_add_mpropdef2npropdef(mpropdef, n_propdef)
                end

                process_default_constructors(n_classdef)
                unsafe_add_mclassdef2nclassdef(mclassdef, n_classdef)

                return n_classdef
        end
end