parser: `Visitor::visit` does not accepts `null`

[nit.git] / src / parser / parser_nodes.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.

# AST nodes of the Nit language
# Was previously based on parser_abs.nit.
package parser_nodes

import location

# Root of the AST class-hierarchy
abstract class ANode
        var _location: nullable Location = null

        # Location is set during AST building. Once built, location cannon be null.
        # However, manual instantiated nodes may need more care.
        fun location: Location do return _location.as(not null)

        # The location of the important part of the node (identifier or whatever)
        fun hot_location: Location do return location

        # Display a message for the colored location of the node
        fun debug(message: String)
        do
                print "{hot_location} {self.class_name}: {message}\n{hot_location.colored_line("0;32")}"
        end

        # Parent of the node in the AST
        readable writable var _parent: nullable ANode = null

        # Protect form invalid instantiation of nodes
        private init do end

        # Remove a child from the AST
        fun remove_child(child: ANode)
        do
                replace_child(child, null)
        end

        # Replace a child with an other node in the AST
        fun replace_child(old_child: ANode, new_child: nullable ANode) is abstract

        # Replace itself with an other node in the AST
        fun replace_with(node: ANode)
        do
                if _parent != null then
                        _parent.replace_child(self, node)
                end
        end

        # Visit all nodes in order.
        # Thus, call `v.enter_visit(e)` for each child `e`
        fun visit_all(v: Visitor) is abstract
end

# Ancestor of all tokens
# A token is a node that has a `text` but no children.
abstract class Token
        super ANode

        # The raw content on the token
        fun text: String is abstract
        fun text=(text: String) is abstract

        redef fun to_s: String do
                return "'{text}'"
        end

        redef fun visit_all(v: Visitor) do end
        redef fun replace_child(old_child: ANode, new_child: nullable ANode) do end
end

# Ancestor of all productions
# A production is a node without text but that usually has children.
abstract class Prod
        super ANode

        fun location=(l: Location) do _location = l

        # All the annotations attached directly to the node
        readable var _n_annotations: nullable AAnnotations = null

        redef fun replace_with(n: ANode)
        do
                super
                assert n isa Prod
                n.location = location
        end
end

# Abstract standard visitor on the AST
abstract class Visitor
        # What the visitor do when a node is visited
        # Concrete visitors should implement this method.
        # @toimplement
        protected fun visit(e: ANode) is abstract

        # Ask the visitor to visit a given node.
        # Usually automatically called by visit_all* methods.
        # This method should not be redefined
        fun enter_visit(e: nullable ANode)
        do
                if e == null then return
                var old = _current_node
                _current_node = e
                visit(e)
                _current_node = old
        end

        # The current visited node
        readable var _current_node: nullable ANode = null
end

# Token of end of line (basically `\n`)
class TEol
        super Token
        redef fun to_s
        do
                return "end of line"
        end
end

# Token of a line of comments
# Starts with the `#` and contains the final end-of-line (if any)
class TComment
        super Token
end

# A token associated with a keyword
abstract class TokenKeyword
        super Token
        redef fun to_s
        do
                return "keyword '{text}'"
        end
end
class TKwmodule
        super TokenKeyword
end
class TKwimport
        super TokenKeyword
end
class TKwclass
        super TokenKeyword
end
class TKwabstract
        super TokenKeyword
end
class TKwinterface
        super TokenKeyword
end
class TKwenum
        super TokenKeyword
end
class TKwend
        super TokenKeyword
end
class TKwmeth
        super TokenKeyword
end
class TKwtype
        super TokenKeyword
end
class TKwinit
        super TokenKeyword
end
class TKwredef
        super TokenKeyword
end
class TKwis
        super TokenKeyword
end
class TKwdo
        super TokenKeyword
end
class TKwreadable
        super TokenKeyword
end
class TKwwritable
        super TokenKeyword
end
class TKwvar
        super TokenKeyword
end
class TKwintern
        super TokenKeyword
end
class TKwextern
        super TokenKeyword
end
class TKwprotected
        super TokenKeyword
end
class TKwprivate
        super TokenKeyword
end
class TKwintrude
        super TokenKeyword
end
class TKwif
        super TokenKeyword
end
class TKwthen
        super TokenKeyword
end
class TKwelse
        super TokenKeyword
end
class TKwwhile
        super TokenKeyword
end
class TKwloop
        super TokenKeyword
end
class TKwfor
        super TokenKeyword
end
class TKwin
        super TokenKeyword
end
class TKwand
        super TokenKeyword
end
class TKwor
        super TokenKeyword
end
class TKwnot
        super TokenKeyword
end
class TKwreturn
        super TokenKeyword
end
class TKwcontinue
        super TokenKeyword
end
class TKwbreak
        super TokenKeyword
end
class TKwabort
        super TokenKeyword
end
class TKwassert
        super TokenKeyword
end
class TKwnew
        super TokenKeyword
end
class TKwisa
        super TokenKeyword
end
class TKwonce
        super TokenKeyword
end
class TKwsuper
        super TokenKeyword
end
class TKwself
        super TokenKeyword
end
class TKwtrue
        super TokenKeyword
end
class TKwfalse
        super TokenKeyword
end
class TKwnull
        super TokenKeyword
end
class TKwas
        super TokenKeyword
end
class TKwnullable
        super TokenKeyword
end
class TKwisset
        super TokenKeyword
end
class TKwlabel
        super TokenKeyword
end
class TKwdebug
        super Token
end
class TOpar
        super Token
end
class TCpar
        super Token
end
class TObra
        super Token
end
class TCbra
        super Token
end
class TComma
        super Token
end
class TColumn
        super Token
end
class TQuad
        super Token
end
class TAssign
        super Token
end

# A token associated with an operator (and other lookalike symbols)
abstract class TokenOperator
        super Token
        redef fun to_s
        do
                return "operator '{text}'"
        end
end
class TPluseq
        super TokenOperator
end
class TMinuseq
        super TokenOperator
end
class TDotdotdot
        super TokenOperator
end
class TDotdot
        super TokenOperator
end
class TDot
        super TokenOperator
end
class TPlus
        super TokenOperator
end
class TMinus
        super TokenOperator
end
class TStar
        super TokenOperator
end
class TSlash
        super TokenOperator
end
class TPercent
        super TokenOperator
end
class TEq
        super TokenOperator
end
class TNe
        super TokenOperator
end
class TLt
        super TokenOperator
end
class TLe
        super TokenOperator
end
class TLl
        super TokenOperator
end
class TGt
        super TokenOperator
end
class TGe
        super TokenOperator
end
class TGg
        super TokenOperator
end
class TStarship
        super TokenOperator
end
class TBang
        super TokenOperator
end
class TAt
        super Token
end

# A class (or formal type) identifier. They start with an uppercase.
class TClassid
        super Token
        redef fun to_s
        do
                do return "type identifier '{text}'"
        end
end

# A standard identifier (variable, method...). They start with a lowercase. 
class TId
        super Token
        redef fun to_s
        do
                do return "identifier '{text}'"
        end
end

# An attribute identifier. They start with an underscore.
class TAttrid
        super Token
        redef fun to_s
        do
                do return "attribute '{text}'"
        end
end

# A token of a literal value (string, integer, etc).
abstract class TokenLiteral
        super Token
        redef fun to_s
        do
                do return "literal value '{text}'"
        end
end
class TNumber
        super TokenLiteral
end
class TFloat
        super TokenLiteral
end
class TChar
        super TokenLiteral
end
class TString
        super TokenLiteral
end
class TStartString
        super TokenLiteral
end
class TMidString
        super TokenLiteral
end
class TEndString
        super Token
end

# A malformed string
class TBadString
        super Token
        redef fun to_s
        do
                do return "malformed string {text}"
        end
end

# A malformed char
class TBadChar
        super Token
        redef fun to_s
        do
                do return "malformed character {text}"
        end
end

class TExternCodeSegment
        super Token
end

# A end of file
class EOF
        super Token
        redef fun to_s
        do
                return "end of file"
        end
end

# A mark of an error
class AError
        super EOF
end
class ALexerError
        super AError
end
class AParserError
        super AError
end

# The main node of a Nit source-file
class AModule
        super Prod

        readable var _n_moduledecl: nullable AModuledecl = null
        readable var _n_imports: List[AImport] = new List[AImport]
        readable var _n_extern_code_blocks: List[AExternCodeBlock] = new List[AExternCodeBlock]
        readable var _n_classdefs: List[AClassdef] = new List[AClassdef]
end

# The declaration of the module with the documentation, name, and annotations
class AModuledecl
        super Prod
        readable var _n_doc: nullable ADoc = null
        readable var _n_kwmodule: TKwmodule
        readable var _n_name: AModuleName
end

# A import clause of a module
abstract class AImport
        super Prod
end

# A standard import clause. eg `import x`
class AStdImport
        super AImport
        readable var _n_visibility: AVisibility
        readable var _n_kwimport: TKwimport
        readable var _n_name: AModuleName
end

# The special import clause of the kernel module. eg `import end`
class ANoImport
        super AImport
        readable var _n_visibility: AVisibility
        readable var _n_kwimport: TKwimport
        readable var _n_kwend: TKwend
end

# A visibility modifier
#
# The public visibility is an empty production (no keyword).
#
# Note: even if some visibilities are only valid on some placse (for instance, no `protected` class or no `intrude` method)
# the parser has no such a restriction, therefore the semantic phases has to check that the visibilities make sense.
abstract class AVisibility
        super Prod
end
class APublicVisibility
        super AVisibility
end
class APrivateVisibility
        super AVisibility
        readable var _n_kwprivate: TKwprivate
end
class AProtectedVisibility
        super AVisibility
        readable var _n_kwprotected: TKwprotected
end
class AIntrudeVisibility
        super AVisibility
        readable var _n_kwintrude: TKwintrude
end

# A class definition
# While most definition are `AStdClassdef`
# There is tow special case of class definition
abstract class AClassdef super Prod
        readable var _n_propdefs: List[APropdef] = new List[APropdef]
end

# A standard class definition with a name, superclasses and properties
class AStdClassdef
        super AClassdef
        readable var _n_doc: nullable ADoc = null
        readable var _n_kwredef: nullable TKwredef = null
        readable var _n_visibility: AVisibility
        readable var _n_classkind: AClasskind
        readable var _n_id: nullable TClassid = null
        readable var _n_formaldefs: List[AFormaldef] = new List[AFormaldef]
        readable var _n_extern_code_block: nullable AExternCodeBlock = null
        readable var _n_superclasses: List[ASuperclass] = new List[ASuperclass]
        readable var _n_kwend: TKwend
        redef fun hot_location do return n_id.location
end

# The implicit class definition of the implicit main method
class ATopClassdef
        super AClassdef
end

# The implicit class definition of the top-level methods
class AMainClassdef
        super AClassdef
end

# The modifier for the kind of class (abstract, interface, etc.)
abstract class AClasskind
        super Prod
end
class AConcreteClasskind
        super AClasskind
        readable var _n_kwclass: TKwclass
end
class AAbstractClasskind
        super AClasskind
        readable var _n_kwabstract: TKwabstract
        readable var _n_kwclass: TKwclass
end
class AInterfaceClasskind
        super AClasskind
        readable var _n_kwinterface: TKwinterface
end
class AEnumClasskind
        super AClasskind
        readable var _n_kwenum: TKwenum
end
class AExternClasskind
        super AClasskind
        readable var _n_kwextern: TKwextern
        readable var _n_kwclass: nullable TKwclass = null
end

# The definition of a formal generic parameter type. eg `X: Y`
class AFormaldef
        super Prod
        readable var _n_id: TClassid
        # The bound of the parameter type
        readable var _n_type: nullable AType = null
end

# A super-class. eg `super X`
class ASuperclass
        super Prod
        readable var _n_kwsuper: TKwsuper
        readable var _n_type: AType
end

# The definition of a property
abstract class APropdef
        super Prod
        readable var _n_doc: nullable ADoc = null
end

# A definition of an attribute
# For historical reason, old-syle and new-style attributes use the same `ANode` sub-class
class AAttrPropdef
        super APropdef
        readable var _n_kwredef: nullable TKwredef = null
        readable var _n_visibility: AVisibility
        readable var _n_kwvar: TKwvar

        # The identifier for an old-style attribute (null if new-style)
        readable var _n_id: nullable TAttrid

        # The identifier for a new-style attribute (null if old-style)
        readable var _n_id2: nullable TId

        readable var _n_type: nullable AType = null
        readable var _n_readable: nullable AAble = null
        readable var _n_writable: nullable AAble = null

        # The initial value, if any
        readable var _n_expr: nullable AExpr = null
        redef fun hot_location
        do
                if n_id != null then return n_id.location else return n_id2.location
        end
end

# A definition of all kind of method (including constructors)
abstract class AMethPropdef
        super APropdef
        readable var _n_kwredef: nullable TKwredef = null
        readable var _n_visibility: nullable AVisibility
        readable var _n_methid: nullable AMethid = null
        readable var _n_signature: nullable ASignature
        redef fun hot_location
        do
                if n_methid != null then
                        return n_methid.location
                else
                        return location
                end
        end
end

# A method marked abstract
# *deferred* is a old synonynmous of *abstract* that comes from PRM, that comes from Eiffel.
class ADeferredMethPropdef
        super AMethPropdef
        readable var _n_kwmeth: TKwmeth
end

# A method marked intern
class AInternMethPropdef
        super AMethPropdef
        readable var _n_kwmeth: TKwmeth
end

# A method of a constructor marked extern
abstract class AExternPropdef
        super AMethPropdef
        readable var _n_extern: nullable TString = null
        readable var _n_extern_calls: nullable AExternCalls = null
        readable var _n_extern_code_block: nullable AExternCodeBlock = null
end

# A method marked extern
class AExternMethPropdef
        super AExternPropdef
        readable var _n_kwmeth: TKwmeth
end

# A method with a body
class AConcreteMethPropdef
        super AMethPropdef
        readable var _n_kwmeth: nullable TKwmeth
        readable var _n_block: nullable AExpr = null
end

# A constructor
abstract class AInitPropdef
        super AMethPropdef
end

# A constructor with a body
class AConcreteInitPropdef
        super AConcreteMethPropdef
        super AInitPropdef
        readable var _n_kwinit: TKwinit
        redef fun hot_location do return n_kwinit.location
end

# A constructor marked extern (defined with the `new` keyword)
class AExternInitPropdef
        super AExternPropdef
        super AInitPropdef
        readable var _n_kwnew: TKwnew
end

# The implicit main method
class AMainMethPropdef
        super AConcreteMethPropdef
end

# Declaration of callbacks for extern methods
class AExternCalls
        super Prod
        readable var _n_kwimport: TKwimport
        readable var _n_extern_calls: List[AExternCall] = new List[AExternCall]
end
abstract class AExternCall
        super Prod
end
abstract class APropExternCall
        super AExternCall
end
class ALocalPropExternCall
        super APropExternCall
        readable var _n_methid: AMethid
end
class AFullPropExternCall
        super APropExternCall
        readable var _n_classid: TClassid
        readable var _n_quad: nullable TQuad = null
        readable var _n_methid: AMethid
end
class AInitPropExternCall
        super APropExternCall
        readable var _n_classid: TClassid
end
class ASuperExternCall
        super AExternCall
        readable var _n_kwsuper: TKwsuper
end
abstract class ACastExternCall
        super AExternCall
end
class ACastAsExternCall
        super ACastExternCall
        readable var _n_from_type: AType
        readable var _n_kwas: TKwas
        readable var _n_to_type: AType
end
class AAsNullableExternCall
        super ACastExternCall
        readable var _n_type: AType
        readable var _n_kwas: TKwas
        readable var _n_kwnullable: TKwnullable
end
class AAsNotNullableExternCall
        super ACastExternCall
        readable var _n_type: AType
        readable var _n_kwas: TKwas
        readable var _n_kwnot: TKwnot
        readable var _n_kwnullable: TKwnullable
end

# A definition of a virtual type
class ATypePropdef
        super APropdef
        readable var _n_kwredef: nullable TKwredef = null
        readable var _n_visibility: AVisibility
        readable var _n_kwtype: TKwtype
        readable var _n_id: TClassid
        readable var _n_type: AType
end

# A `writable` or `readable` modifier
abstract class AAble
        super Prod
        readable var _n_visibility: nullable AVisibility = null
        readable var _n_kwredef: nullable TKwredef = null
end

# A `readable` modifier
class AReadAble
        super AAble
        readable var _n_kwreadable: TKwreadable
end

# A `writable` modifier
class AWriteAble
        super AAble
        readable var _n_kwwritable: TKwwritable
end

# The identifier of a method in a method declaration.
# There is a specific class because of operator and setters.
abstract class AMethid
        super Prod
end
class AIdMethid
        super AMethid
        readable var _n_id: TId
end
class APlusMethid
        super AMethid
        readable var _n_plus: TPlus
end
class AMinusMethid
        super AMethid
        readable var _n_minus: TMinus
end
class AStarMethid
        super AMethid
        readable var _n_star: TStar
end
class ASlashMethid
        super AMethid
        readable var _n_slash: TSlash
end
class APercentMethid
        super AMethid
        readable var _n_percent: TPercent
end
class AEqMethid
        super AMethid
        readable var _n_eq: TEq
end
class ANeMethid
        super AMethid
        readable var _n_ne: TNe
end
class ALeMethid
        super AMethid
        readable var _n_le: TLe
end
class AGeMethid
        super AMethid
        readable var _n_ge: TGe
end
class ALtMethid
        super AMethid
        readable var _n_lt: TLt
end
class AGtMethid
        super AMethid
        readable var _n_gt: TGt
end
class ALlMethid
        super AMethid
        readable writable var _n_ll: TLl
end
class AGgMethid
        super AMethid
        readable writable var _n_gg: TGg
end
class ABraMethid
        super AMethid
        readable var _n_obra: TObra
        readable var _n_cbra: TCbra
end
class AStarshipMethid
        super AMethid
        readable var _n_starship: TStarship
end
class AAssignMethid
        super AMethid
        readable var _n_id: TId
        readable var _n_assign: TAssign
end
class ABraassignMethid
        super AMethid
        readable var _n_obra: TObra
        readable var _n_cbra: TCbra
        readable var _n_assign: TAssign
end

# A signature in a method definition. eg `(x,y:X,z:Z):T`
class ASignature
        super Prod
        readable var _n_opar: nullable TOpar = null
        readable var _n_params: List[AParam] = new List[AParam]
        readable var _n_cpar: nullable TCpar = null
        readable var _n_type: nullable AType = null
        readable var _n_closure_decls: List[AClosureDecl] = new List[AClosureDecl]
end

# A parameter definition in a signature. eg `x:X`
class AParam
        super Prod
        readable var _n_id: TId
        readable var _n_type: nullable AType = null
        readable var _n_dotdotdot: nullable TDotdotdot = null
end

class AClosureDecl
        super Prod
        readable var _n_kwbreak: nullable TKwbreak = null
        readable var _n_bang: TBang
        readable var _n_id: TId
        readable var _n_signature: ASignature
        readable var _n_expr: nullable AExpr = null
end

# A static type. eg `nullable X[Y]`
class AType
        super Prod
        readable var _n_kwnullable: nullable TKwnullable = null

        # The name of the class or of the formal type
        readable var _n_id: TClassid

        # Type arguments for a generic type
        readable var _n_types: List[AType] = new List[AType]
end

# A label at the end of a block or in a break/continue statement. eg `label x`
class ALabel
        super Prod
        readable var _n_kwlabel: TKwlabel
        readable var _n_id: TId
end

# Expression and statements
# From a AST point of view there is no distinction between statement and expressions (even if the parser has to distinguish them)
abstract class AExpr
        super Prod
end

# A sequence of AExpr (usually statements)
# The last AExpr gives the value of the whole block
class ABlockExpr
        super AExpr
        readable var _n_expr: List[AExpr] = new List[AExpr]
        readable var _n_kwend: nullable TKwend = null
end

# A declaration of a local variable. eg `var x: X = y`
class AVardeclExpr
        super AExpr
        readable var _n_kwvar: TKwvar
        readable var _n_id: TId
        readable var _n_type: nullable AType = null
        readable var _n_assign: nullable TAssign = null

        # The initial value, if any
        readable var _n_expr: nullable AExpr = null
end

# A `return` statement. eg `return x`
class AReturnExpr
        super AExpr
        readable var _n_kwreturn: nullable TKwreturn = null
        readable var _n_expr: nullable AExpr = null
end

# Something that has a label.
abstract class ALabelable
        super Prod
        readable var _n_label: nullable ALabel = null
end

# A `break` statement.
class ABreakExpr
        super AExpr
        super ALabelable
        readable var _n_kwbreak: TKwbreak
        readable var _n_expr: nullable AExpr = null
end

# An `abort` statement
class AAbortExpr
        super AExpr
        readable var _n_kwabort: TKwabort
end

# A `continue` statement
class AContinueExpr
        super AExpr
        super ALabelable
        readable var _n_kwcontinue: nullable TKwcontinue = null
        readable var _n_expr: nullable AExpr = null
end

# A `do` statement
class ADoExpr
        super AExpr
        super ALabelable
        readable var _n_kwdo: TKwdo
        readable var _n_block: nullable AExpr = null
end

# A `if` statement
class AIfExpr
        super AExpr
        readable var _n_kwif: TKwif
        readable var _n_expr: AExpr
        readable var _n_then: nullable AExpr = null
        readable var _n_else: nullable AExpr = null
end

# A `if` expression
class AIfexprExpr
        super AExpr
        readable var _n_kwif: TKwif
        readable var _n_expr: AExpr
        readable var _n_kwthen: TKwthen
        readable var _n_then: AExpr
        readable var _n_kwelse: TKwelse
        readable var _n_else: AExpr
end

# A `while` statement
class AWhileExpr
        super AExpr
        super ALabelable
        readable var _n_kwwhile:  TKwwhile
        readable var _n_expr: AExpr
        readable var _n_kwdo: TKwdo
        readable var _n_block: nullable AExpr = null
end

# A `loop` statement
class ALoopExpr
        super AExpr
        super ALabelable
        readable var _n_kwloop: TKwloop
        readable var _n_block: nullable AExpr = null
end

# A `for` statement
class AForExpr
        super AExpr
        super ALabelable
        readable var _n_kwfor: TKwfor
        readable var _n_ids: List[TId] = new List[TId]
        readable var _n_expr: AExpr
        readable var _n_kwdo: TKwdo
        readable var _n_block: nullable AExpr = null
end

# An `assert` statement
class AAssertExpr
        super AExpr
        readable var _n_kwassert: TKwassert
        readable var _n_id: nullable TId = null
        readable var _n_expr: AExpr
        readable var _n_else: nullable AExpr = null
end

# Whatever is a simple assignment. eg `= something`
abstract class AAssignFormExpr
        super AExpr
        readable var _n_assign: TAssign
        readable var _n_value: AExpr
end

# Whatever is a combined assignment. eg `+= something`
abstract class AReassignFormExpr
        super AExpr
        readable var _n_assign_op: AAssignOp
        readable var _n_value: AExpr
end

# A `once` expression. eg `once x`
class AOnceExpr
        super AProxyExpr
        readable var _n_kwonce: TKwonce
end

# A polymorphic invocation of a method
# The form of the invocation (name, arguments, etc) are specific
abstract class ASendExpr
        super AExpr
        # The receiver of the method invocation
        readable var _n_expr: AExpr
        readable var _n_closure_defs: List[AClosureDef] = new List[AClosureDef]
end

# A binary operation on a method
abstract class ABinopExpr
        super ASendExpr
        # The second operand of the operation
        # Note: the receiver (`n_expr`) is the first operand
        readable var _n_expr2: AExpr
end

# Something that is boolean expression
abstract class ABoolExpr
        super AExpr
end

# A `or` expression 
class AOrExpr
        super ABoolExpr
        readable var _n_expr: AExpr
        readable var _n_expr2: AExpr
end

# A `and` expression
class AAndExpr
        super ABoolExpr
        readable var _n_expr: AExpr
        readable var _n_expr2: AExpr
end

# A `or else` expression
class AOrElseExpr
        super ABoolExpr
        readable var _n_expr: AExpr
        readable var _n_expr2: AExpr
end

# A `not` expression
class ANotExpr
        super ABoolExpr
        readable var _n_kwnot: TKwnot
        readable var _n_expr: AExpr
end

# A `==` expression
class AEqExpr
        super ABinopExpr
end

# A `is` expression
class AEeExpr
        super ABoolExpr
        readable var _n_expr: AExpr
        readable var _n_expr2: AExpr
end

# A `!=` expression
class ANeExpr
        super ABinopExpr
end

# A `<` expression
class ALtExpr
        super ABinopExpr
end

# A `<=` expression
class ALeExpr
        super ABinopExpr
end

# A `<<` expression
class ALlExpr
        super ABinopExpr
end

# A `>` expression
class AGtExpr
        super ABinopExpr
end

# A `>=` expression
class AGeExpr
        super ABinopExpr
end

# A `>>` expression
class AGgExpr
        super ABinopExpr
end

# A type-ckeck expression. eg `x isa T`
class AIsaExpr
        super ABoolExpr
        readable var _n_expr: AExpr
        readable var _n_type: AType
end

# A `+` expression
class APlusExpr
        super ABinopExpr
end

# A `-` expression
class AMinusExpr
        super ABinopExpr
end

# A `<=>` expression
class AStarshipExpr
        super ABinopExpr
end

# A `*` expression
class AStarExpr
        super ABinopExpr
end

# A `/` expression
class ASlashExpr
        super ABinopExpr
end

# A `%` expression
class APercentExpr
        super ABinopExpr
end

# A unary minus expression. eg `-x`
class AUminusExpr
        super ASendExpr
        readable var _n_minus: TMinus
end

# An explicit instantiation. eg `new T`
class ANewExpr
        super AExpr
        readable var _n_kwnew: TKwnew
        readable var _n_type: AType

        # The name of the named-constructor, if any
        readable var _n_id: nullable TId = null
        readable var _n_args: AExprs
end

# Whatever is a old-style attribute access
abstract class AAttrFormExpr
        super AExpr

        # The receiver of the attribute
        readable var _n_expr: AExpr

        # The name of the attribute
        readable var _n_id: TAttrid
end

# The read of an attribute. eg `x._a`
class AAttrExpr
        super AAttrFormExpr
end

# The assignment of an attribute. eg `x._a=y`
class AAttrAssignExpr
        super AAttrFormExpr
        super AAssignFormExpr
end

# Whatever looks-like a call with a standard method and any number of arguments.
abstract class ACallFormExpr
        super ASendExpr

        # The name of the method
        readable var _n_id: TId

        # The arguments of the call
        readable var _n_args: AExprs
end

# A complex setter call (standard or brackets)
abstract class ASendReassignFormExpr
        super ASendExpr
        super AReassignFormExpr
end

# A complex attribute assignment. eg `x._a+=y`
class AAttrReassignExpr
        super AAttrFormExpr
        super AReassignFormExpr
end

# A call with a standard method-name and any number of arguments. eg `x.m(y)`. OR just a simple id
# Note: because the parser cannot distinguish a variable read with a method call with an implicit receiver and no arguments. it always returns a ACallExpr.
# Semantic analysis have to transform them to instance of `AVarExpr`.
class ACallExpr
        super ACallFormExpr
end

# A setter call with a standard method-name and any number of arguments. eg `x.m(y)=z`. OR just a simple assignment.
# Note: because the parser cannot distinguish a variable write with a setter call with an implicit receiver and no arguments. it always returns a ACallAssignExpr.
# Semantic analysis have to transform them to instance of `AVarAssignExpr`.
class ACallAssignExpr
        super ACallFormExpr
        super AAssignFormExpr
end

# A complex setter call with a standard method-name and any number of arguments. eg `x.m(y)+=z`. OR just a simple complex assignment.
# Note: because the parser cannot distinguish a variable write with a compex setter call with an implicit receiver and no arguments. it always returns a ACallReassignExpr.
# Semantic analysis have to transform them to instance of `AVarReassignExpr`.
class ACallReassignExpr
        super ACallFormExpr
        super ASendReassignFormExpr
end

# A call to `super`. OR a call of a super-constructor
class ASuperExpr
        super AExpr
        readable var _n_qualified: nullable AQualified = null
        readable var _n_kwsuper: TKwsuper
        readable var _n_args: AExprs
end

# A call to the `init` constructor.
# Note: because `init` is a keyword and not a `TId`, the explicit call to init cannot be a ACallFormExpr
class AInitExpr
        super ASendExpr
        readable var _n_kwinit: TKwinit
        readable var _n_args: AExprs
end

# Whatever looks-like a call of the brackets `[]` operator.
abstract class ABraFormExpr
        super ASendExpr
        readable var _n_args: AExprs
end

# A call of the brackets operator. eg `x[y,z]`
class ABraExpr
        super ABraFormExpr
end

# A setter call of the bracket operator. eg `x[y,z]=t`
class ABraAssignExpr
        super ABraFormExpr
        super AAssignFormExpr
end

# Whatever is an access to a local variable
abstract class AVarFormExpr
        super AExpr
        readable var _n_id: TId
end

# A complex setter call of the bracket operator. eg `x[y,z]+=t`
class ABraReassignExpr
        super ABraFormExpr
        super ASendReassignFormExpr
end

class AClosureCallExpr
        super AExpr
        readable var _n_id: TId
        readable var _n_args: AExprs
        readable var _n_closure_defs: List[AClosureDef] = new List[AClosureDef]
end

# A local variable read access.
# The parser cannot instantiate them, see `ACallExpr`.
class AVarExpr
        super AVarFormExpr
end

# A local variable simple assigment access
# The parser cannot instantiate them, see `ACallAssingExpr`.
class AVarAssignExpr
        super AVarFormExpr
        super AAssignFormExpr
end

# A local variable complex assignment access
# The parser cannot instantiate them, see `ACallReassingExpr`.
class AVarReassignExpr
        super AVarFormExpr
        super AReassignFormExpr
end

# A literal range, open or closed
abstract class ARangeExpr
        super AExpr
        readable var _n_expr: AExpr
        readable var _n_expr2: AExpr
end

# A closed literal range. eg `[x..y]`
class ACrangeExpr
        super ARangeExpr
        readable var _n_obra: TObra
        readable var _n_cbra: TCbra
end

# An open literal range. eg `[x..y[`
class AOrangeExpr
        super ARangeExpr
        readable var _n_obra: TObra
        readable var _n_cbra: TObra
end

# A literal array. eg. `[x,y,z]`
class AArrayExpr
        super AExpr
        readable var _n_exprs: AExprs
end

# A read of `self` 
class ASelfExpr
        super AExpr
        readable var _n_kwself: nullable TKwself
end

# When there is no explicit receiver, `self` is implicit
class AImplicitSelfExpr
        super ASelfExpr
end

# A `true` boolean literal constant
class ATrueExpr
        super ABoolExpr
        readable var _n_kwtrue: TKwtrue
end
# A `false` boolean literal constant
class AFalseExpr
        super ABoolExpr
        readable var _n_kwfalse: TKwfalse
end
# A `null` literal constant
class ANullExpr
        super AExpr
        readable var _n_kwnull: TKwnull
end
# An integer literal
class AIntExpr
        super AExpr
        readable var _n_number: TNumber
end
# A float literal
class AFloatExpr
        super AExpr
        readable var _n_float: TFloat
end
# A character literal
class ACharExpr
        super AExpr
        readable var _n_char: TChar
end
# A string literal
abstract class AStringFormExpr
        super AExpr
        readable var _n_string: Token
end

# A simple string. eg. `"abc"`
class AStringExpr
        super AStringFormExpr
end

# The start of a superstring. eg `"abc{`
class AStartStringExpr
        super AStringFormExpr
end

# The middle of a superstring. eg `}abc{`
class AMidStringExpr
        super AStringFormExpr
end

# The end of a superstrng. eg `}abc"`
class AEndStringExpr
        super AStringFormExpr
end

# A superstring literal. eg "a{x}b{y}c"
# Each part is modelized a sequence of expression. eg. ["a{, x, }b{, y, }c"]
class ASuperstringExpr
        super AExpr
        readable var _n_exprs: List[AExpr] = new List[AExpr]
end

# A simple parenthesis. eg `(x)`
class AParExpr
        super AProxyExpr
        readable var _n_opar: TOpar
        readable var _n_cpar: TCpar
end

# Whatevej just contains (and mimic) an other expression
abstract class AProxyExpr
        super AExpr
        readable var _n_expr: AExpr
end

# A type cast. eg `x.as(T)`
class AAsCastExpr
        super AExpr
        readable var _n_expr: AExpr
        readable var _n_kwas: TKwas
        readable var _n_opar: TOpar
        readable var _n_type: AType
        readable var _n_cpar: TCpar
end

# A as-not-null cast. eg `x.as(not null)`
class AAsNotnullExpr
        super AExpr
        readable var _n_expr: AExpr
        readable var _n_kwas: TKwas
        readable var _n_opar: TOpar
        readable var _n_kwnot: TKwnot
        readable var _n_kwnull: TKwnull
        readable var _n_cpar: TCpar
end

# A is-set check of old-style attributes. eg `isset x._a`
class AIssetAttrExpr
        super AAttrFormExpr
        readable var _n_kwisset: TKwisset
end

# A list of expression separated with commas (arguments for instance)
abstract class AExprs
        super Prod 
        readable var _n_exprs: List[AExpr] = new List[AExpr]
end

class ADebugTypeExpr
        super AExpr
        readable var _n_kwdebug: TKwdebug
        readable var _n_kwtype: TKwtype
        readable var _n_expr: AExpr
        readable var _n_type: AType
end

# A simple list of expressions
class AListExprs
        super AExprs
end

# A list of expressions enclosed in parentheses
class AParExprs
        super AExprs
        readable var _n_opar: TOpar
        readable var _n_cpar: TCpar
end

# A list of expressions enclosed in brackets
class ABraExprs
        super AExprs
        readable var _n_obra: TObra
        readable var _n_cbra: TCbra
end

# A complex assignment operator. eg `+=`
abstract class AAssignOp
        super Prod
end
class APlusAssignOp
        super AAssignOp
        readable var _n_pluseq: TPluseq
end
class AMinusAssignOp
        super AAssignOp
        readable var _n_minuseq: TMinuseq
end

class AClosureDef
        super ALabelable
        readable var _n_bang: TBang
        readable var _n_id: AClosureId
        readable var _n_ids: List[TId] = new List[TId]
        readable var _n_kwdo: nullable TKwdo = null
        readable var _n_expr: nullable AExpr = null
        redef fun hot_location do return n_id.location
end
abstract class AClosureId
        super Prod
end
class ASimpleClosureId
        super AClosureId
        readable var _n_id: TId
end
class ABreakClosureId
        super AClosureId
        readable var _n_kwbreak: TKwbreak
end
class AModuleName
        super Prod
        readable var _n_quad: nullable TQuad = null
        readable var _n_path: List[TId] = new List[TId]
        readable var _n_id: TId
end
class AInLanguage
        super Prod
        readable var _n_kwin: TKwin
        readable var _n_string: TString
end
class AExternCodeBlock
        super Prod
        readable var _n_in_language: nullable AInLanguage = null
        readable var _n_extern_code_segment: TExternCodeSegment
end
class AQualified
        super Prod
        readable var _n_quad: nullable TQuad = null
        readable var _n_id: List[TId] = new List[TId]
        readable var _n_classid: nullable TClassid = null
end

# A documentation of a definition
# It contains the block of comments just above the declaration
class ADoc
        super Prod
        readable var _n_comment: List[TComment] = new List[TComment]
end

class AAnnotations
        super Prod
        readable var _n_at: nullable TAt = null
        readable var _n_opar: nullable TOpar = null
        readable var _n_items: List[AAnnotation] = new List[AAnnotation]
        readable var _n_cpar: nullable TCpar = null
end
class AAnnotation
        super Prod
        readable var _n_atid: AAtid
        readable var _n_opar: nullable TOpar = null
        readable var _n_args: List[AAtArg] = new List[AAtArg]
        readable var _n_cpar: nullable TCpar = null
end
abstract class AAtArg
        super Prod
end
class ATypeAtArg
        super AAtArg
        readable var _n_type: AType
end
class AExprAtArg
        super AAtArg
        readable var _n_expr: AExpr
end
class AAtAtArg
        super AAtArg
end
abstract class AAtid
        super Prod
        readable var _n_id: Token
end
class AIdAtid
        super AAtid
end
class AKwexternAtid
        super AAtid
end
class AKwinternAtid
        super AAtid
end
class AKwreadableAtid
        super AAtid
end
class AKwwritableAtid
        super AAtid
end
class AKwimportAtid
        super AAtid
end

# The root of the AST
class Start
        super Prod
        readable var _n_base: nullable AModule
        readable var _n_eof: EOF
        init(n_base: nullable AModule, n_eof: EOF)
        do
                self._n_base = n_base
                self._n_eof = n_eof
        end
end