[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.
module parser_nodes

import location

# Root of the AST class-hierarchy
abstract class ANode
        # Location is set during AST building. Once built, location cannon be null.
        # However, manual instantiated nodes may need more care.
        var location: Location is writable, noinit

        # 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
                sys.stderr.write "{hot_location} {self.class_name}: {message}\n{hot_location.colored_line("0;32")}\n"
        end

        # Parent of the node in the AST
        var parent: nullable ANode = null

        # The topmost ancestor of the element
        # This just apply `parent` until the first one
        fun root: ANode
        do
                var res = self
                loop
                        var p = res.parent
                        if p == null then return res
                        res = p
                end
        end

        # The most specific common parent between `self` and `other`
        # Return null if the two node are unrelated (distinct root)
        fun common_parent(other: ANode): nullable ANode
        do
                # First, get the same depth
                var s: nullable ANode = self
                var o: nullable ANode = other
                var d = s.depth - o.depth
                while d > 0 do
                        s = s.parent
                        d -= 1
                end
                while d < 0 do
                        o = o.parent
                        d += 1
                end
                assert o.depth == s.depth
                # Second, go up until same in found
                while s != o do
                        s = s.parent
                        o = o.parent
                end
                return s
        end

        # Number of nodes between `self` and the `root` of the AST
        # ENSURE `self == self.root implies result == 0 `
        # ENSURE `self != self.root implies result == self.parent.depth + 1`
        fun depth: Int
        do
                var n = self
                var res = 0
                loop
                        var p = n.parent
                        if p == null then return res
                        n = p
                        res += 1
                end
        end

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

        # Detach a node from its parent
        # Aborts if the node is not detashable. use `replace_with` instead
        # REQUIRE: parent != null
        # REQUIRE: is_detachable
        # ENDURE: parent == null
        fun detach
        do
                assert parent != null
                parent.replace_child(self, null)
                parent = null
        end

        # Replace itself with an other node in the AST
        # REQUIRE: parent != null
        # ENSURE: node.parent == old(parent)
        # ENSURE: parent == null
        fun replace_with(node: ANode)
        do
                assert parent != null
                parent.replace_child(self, node)
                parent = null
        end

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

# A sequence of nodes
# There is a specifc class (instead of a using Array) to track the parent/child relation when nodes are added or removed
class ANodes[E: ANode]
        super Sequence[E]
        private var parent: ANode
        private var items = new Array[E]
        redef fun iterator do return items.iterator
        redef fun length do return items.length
        redef fun is_empty do return items.is_empty
        redef fun push(e)
        do
                hook_add(e)
                items.push(e)
        end
        redef fun pop
        do
                var res = items.pop
                hook_remove(res)
                return res
        end
        redef fun unshift(e)
        do
                hook_add(e)
                items.unshift(e)
        end
        redef fun shift
        do
                var res = items.shift
                hook_remove(res)
                return res
        end
        redef fun has(e)
        do
                return items.has(e)
        end
        redef fun [](index)
        do
                return items[index]
        end
        redef fun []=(index, e)
        do
                hook_remove(self[index])
                hook_add(e)
                items[index]=e
        end
        redef fun remove_at(index)
        do
                hook_remove(items[index])
                items.remove_at(index)
        end
        private fun hook_add(e: E)
        do
                #assert e.parent == null
                e.parent = parent
        end
        private fun hook_remove(e: E)
        do
                assert e.parent == parent
                e.parent = null
        end

        # Used in parent contructor to fill elements
        private fun unsafe_add_all(nodes: Collection[Object])
        do
                var parent = self.parent
                for n in nodes do
                        assert n isa E
                        add n
                        n.parent = parent
                end
        end

        private fun replace_child(old_child: ANode, new_child: nullable ANode): Bool
        do
                var parent = self.parent
                for i in [0..length[ do
                        if self[i] == old_child then
                                if new_child != null then
                                        assert new_child isa E
                                        self[i] = new_child
                                        new_child.parent = parent
                                else
                                        self.remove_at(i)
                                end
                                return true
                        end
                end
                return false
        end

        private fun visit_all(v: Visitor)
        do
                for n in self do v.enter_visit(n)
        end
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

        # The previous token in the Lexer.
        # May have disapeared in the AST
        var prev_token: nullable Token = null

        # The next token in the Lexer.
        # May have disapeared in the AST
        var next_token: nullable Token = null

        # The verbatim blank text between `prev_token` and `self`
        fun blank_before: String
        do
                if prev_token == null then return ""
                var from = prev_token.location.pend+1
                var to = location.pstart
                return location.file.string.substring(from,to-from)
        end

        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

redef class SourceFile
        # The first token parser by the lexer
        # May have disapeared in the final AST
        var first_token: nullable Token = null

        # The first token parser by the lexer
        # May have disapeared in the final AST
        var last_token: nullable Token = null
end

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

        # All the annotations attached directly to the node
        var n_annotations: nullable AAnnotations = null is writable

        redef fun replace_with(n: ANode)
        do
                super
                assert n isa Prod
                if not isset n._location and isset _location then 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
        var current_node: nullable ANode = null is writable
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 TKwpackage
        super TokenKeyword
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 TKwvar
        super TokenKeyword
end
class TKwextern
        super TokenKeyword
end
class TKwpublic
        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 TKwimplies
        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 Token
end
class TDotdot
        super Token
end
class TDot
        super Token
end
class TPlus
        super TokenOperator
end
class TMinus
        super TokenOperator
end
class TStar
        super TokenOperator
end
class TStarstar
        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 THexNumber
        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 TokenLiteral
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

        var n_moduledecl: nullable AModuledecl = null is writable
        var n_imports: ANodes[AImport] = new ANodes[AImport](self)
        var n_extern_code_blocks: ANodes[AExternCodeBlock] = new ANodes[AExternCodeBlock](self)
        var n_classdefs: ANodes[AClassdef] = new ANodes[AClassdef](self)
end

# The declaration of the module with the documentation, name, and annotations
class AModuledecl
        super Prod
        var n_doc: nullable ADoc = null is writable
        var n_kwredef: nullable TKwredef = null is writable
        var n_visibility: AVisibility is writable, noinit
        var n_kwmodule: TKwmodule is writable, noinit
        var n_name: AModuleName is writable, noinit
end

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

# A standard import clause. eg `import x`
class AStdImport
        super AImport
        var n_visibility: AVisibility is writable, noinit
        var n_kwimport: TKwimport is writable, noinit
        var n_name: AModuleName is writable, noinit
end

# The special import clause of the kernel module. eg `import end`
class ANoImport
        super AImport
        var n_visibility: AVisibility is writable, noinit
        var n_kwimport: TKwimport is writable, noinit
        var n_kwend: TKwend is writable, noinit
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
        var n_kwpublic: nullable TKwpublic is writable
end
class APrivateVisibility
        super AVisibility
        var n_kwprivate: TKwprivate is writable, noinit
end
class AProtectedVisibility
        super AVisibility
        var n_kwprotected: TKwprotected is writable, noinit
end
class AIntrudeVisibility
        super AVisibility
        var n_kwintrude: TKwintrude is writable, noinit
end

# A class definition
# While most definition are `AStdClassdef`
# There is tow special case of class definition
abstract class AClassdef
        super Prod
        var n_propdefs: ANodes[APropdef] = new ANodes[APropdef](self)
end

# A standard class definition with a name, superclasses and properties
class AStdClassdef
        super AClassdef
        var n_doc: nullable ADoc = null is writable
        var n_kwredef: nullable TKwredef = null is writable
        var n_visibility: AVisibility is writable, noinit
        var n_classkind: AClasskind is writable, noinit
        var n_id: nullable TClassid = null is writable
        var n_formaldefs: ANodes[AFormaldef] = new ANodes[AFormaldef](self)
        var n_extern_code_block: nullable AExternCodeBlock = null is writable
        var n_superclasses: ANodes[ASuperclass] = new ANodes[ASuperclass](self)
        var n_kwend: TKwend is writable, noinit
        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
        var n_kwclass: TKwclass is writable, noinit
end
class AAbstractClasskind
        super AClasskind
        var n_kwabstract: TKwabstract is writable, noinit
        var n_kwclass: TKwclass is writable, noinit
end
class AInterfaceClasskind
        super AClasskind
        var n_kwinterface: TKwinterface is writable, noinit
end
class AEnumClasskind
        super AClasskind
        var n_kwenum: TKwenum is writable, noinit
end
class AExternClasskind
        super AClasskind
        var n_kwextern: TKwextern is writable, noinit
        var n_kwclass: nullable TKwclass = null is writable
end

# The definition of a formal generic parameter type. eg `X: Y`
class AFormaldef
        super Prod
        var n_id: TClassid is writable, noinit
        # The bound of the parameter type
        var n_type: nullable AType = null is writable
end

# A super-class. eg `super X`
class ASuperclass
        super Prod
        var n_kwsuper: TKwsuper is writable, noinit
        var n_type: AType is writable, noinit
end

# The definition of a property
abstract class APropdef
        super Prod
        var n_doc: nullable ADoc = null is writable
        var n_kwredef: nullable TKwredef = null is writable
        var n_visibility: nullable AVisibility = null is writable
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
        var n_kwvar: TKwvar is writable, noinit

        # The identifier for a new-style attribute (null if old-style)
        var n_id2: TId is writable, noinit

        var n_type: nullable AType = null is writable

        # The initial value, if any
        var n_expr: nullable AExpr = null is writable
        redef fun hot_location
        do
                return n_id2.location
        end
end

# A definition of all kind of method (including constructors)
class AMethPropdef
        super APropdef
        var n_kwmeth: nullable TKwmeth = null is writable
        var n_kwinit: nullable TKwinit = null is writable
        var n_kwnew: nullable TKwnew = null is writable
        var n_methid: nullable AMethid = null is writable
        var n_signature: nullable ASignature = null is writable
        var n_block: nullable AExpr = null is writable
        var n_extern_calls: nullable AExternCalls = null is writable
        var n_extern_code_block: nullable AExternCodeBlock = null is writable
        redef fun hot_location
        do
                if n_methid != null then
                        return n_methid.location
                else if n_kwinit != null then
                        return n_kwinit.location
                else if n_kwnew != null then
                        return n_kwnew.location
                else
                        return location
                end
        end
end

# The implicit main method
class AMainMethPropdef
        super AMethPropdef
end

# Declaration of callbacks for extern methods
class AExternCalls
        super Prod
        var n_kwimport: TKwimport is writable, noinit
        var n_extern_calls: ANodes[AExternCall] = new ANodes[AExternCall](self)
end
abstract class AExternCall
        super Prod
end
abstract class APropExternCall
        super AExternCall
end
class ALocalPropExternCall
        super APropExternCall
        var n_methid: AMethid is writable, noinit
end
class AFullPropExternCall
        super APropExternCall
        var n_type: AType is writable, noinit
        var n_dot: nullable TDot = null is writable
        var n_methid: AMethid is writable, noinit
end
class AInitPropExternCall
        super APropExternCall
        var n_type: AType is writable, noinit
end
class ASuperExternCall
        super AExternCall
        var n_kwsuper: TKwsuper is writable, noinit
end
abstract class ACastExternCall
        super AExternCall
end
class ACastAsExternCall
        super ACastExternCall
        var n_from_type: AType is writable, noinit
        var n_dot: nullable TDot = null is writable
        var n_kwas: TKwas is writable, noinit
        var n_to_type: AType is writable, noinit
end
class AAsNullableExternCall
        super ACastExternCall
        var n_type: AType is writable, noinit
        var n_kwas: TKwas is writable, noinit
        var n_kwnullable: TKwnullable is writable, noinit
end
class AAsNotNullableExternCall
        super ACastExternCall
        var n_type: AType is writable, noinit
        var n_kwas: TKwas is writable, noinit
        var n_kwnot: TKwnot is writable, noinit
        var n_kwnullable: TKwnullable is writable, noinit
end

# A definition of a virtual type
class ATypePropdef
        super APropdef
        var n_kwtype: TKwtype is writable, noinit
        var n_id: TClassid is writable, noinit
        var n_type: AType is writable, noinit
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
        var n_id: TId is writable, noinit
end
class APlusMethid
        super AMethid
        var n_plus: TPlus is writable, noinit
end
class AMinusMethid
        super AMethid
        var n_minus: TMinus is writable, noinit
end
class AStarMethid
        super AMethid
        var n_star: TStar is writable, noinit
end
class AStarstarMethid
        super AMethid
        var n_starstar: TStarstar is writable, noinit
end
class ASlashMethid
        super AMethid
        var n_slash: TSlash is writable, noinit
end
class APercentMethid
        super AMethid
        var n_percent: TPercent is writable, noinit
end
class AEqMethid
        super AMethid
        var n_eq: TEq is writable, noinit
end
class ANeMethid
        super AMethid
        var n_ne: TNe is writable, noinit
end
class ALeMethid
        super AMethid
        var n_le: TLe is writable, noinit
end
class AGeMethid
        super AMethid
        var n_ge: TGe is writable, noinit
end
class ALtMethid
        super AMethid
        var n_lt: TLt is writable, noinit
end
class AGtMethid
        super AMethid
        var n_gt: TGt is writable, noinit
end
class ALlMethid
        super AMethid
        var n_ll: TLl is writable, noinit
end
class AGgMethid
        super AMethid
        var n_gg: TGg is writable, noinit
end
class ABraMethid
        super AMethid
        var n_obra: TObra is writable, noinit
        var n_cbra: TCbra is writable, noinit
end
class AStarshipMethid
        super AMethid
        var n_starship: TStarship is writable, noinit
end
class AAssignMethid
        super AMethid
        var n_id: TId is writable, noinit
        var n_assign: TAssign is writable, noinit
end
class ABraassignMethid
        super AMethid
        var n_obra: TObra is writable, noinit
        var n_cbra: TCbra is writable, noinit
        var n_assign: TAssign is writable, noinit
end

# A signature in a method definition. eg `(x,y:X,z:Z):T`
class ASignature
        super Prod
        var n_opar: nullable TOpar = null is writable
        var n_params: ANodes[AParam] = new ANodes[AParam](self)
        var n_cpar: nullable TCpar = null is writable
        var n_type: nullable AType = null is writable
end

# A parameter definition in a signature. eg `x:X`
class AParam
        super Prod
        var n_id: TId is writable, noinit
        var n_type: nullable AType = null is writable
        var n_dotdotdot: nullable TDotdotdot = null is writable
end

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

        # The name of the class or of the formal type
        var n_id: TClassid is writable, noinit

        # Type arguments for a generic type
        var n_types: ANodes[AType] = new ANodes[AType](self)
end

# A label at the end of a block or in a break/continue statement. eg `label x`
class ALabel
        super Prod
        var n_kwlabel: TKwlabel is writable, noinit
        var n_id: nullable TId is writable
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
        var n_expr: ANodes[AExpr] = new ANodes[AExpr](self)
        var n_kwend: nullable TKwend = null is writable
end

# A declaration of a local variable. eg `var x: X = y`
class AVardeclExpr
        super AExpr
        var n_kwvar: TKwvar is writable, noinit
        var n_id: TId is writable, noinit
        var n_type: nullable AType = null is writable
        var n_assign: nullable TAssign = null is writable

        # The initial value, if any
        var n_expr: nullable AExpr = null is writable
end

# A `return` statement. eg `return x`
class AReturnExpr
        super AExpr
        var n_kwreturn: nullable TKwreturn = null is writable
        var n_expr: nullable AExpr = null is writable
end

# Something that has a label.
abstract class ALabelable
        super Prod
        var n_label: nullable ALabel = null is writable
end

# A `break` statement.
class ABreakExpr
        super AExpr
        super ALabelable
        var n_kwbreak: TKwbreak is writable, noinit
        var n_expr: nullable AExpr = null is writable
end

# An `abort` statement
class AAbortExpr
        super AExpr
        var n_kwabort: TKwabort is writable, noinit
end

# A `continue` statement
class AContinueExpr
        super AExpr
        super ALabelable
        var n_kwcontinue: nullable TKwcontinue = null is writable
        var n_expr: nullable AExpr = null is writable
end

# A `do` statement
class ADoExpr
        super AExpr
        super ALabelable
        var n_kwdo: TKwdo is writable, noinit
        var n_block: nullable AExpr = null is writable
end

# A `if` statement
class AIfExpr
        super AExpr
        var n_kwif: TKwif is writable, noinit
        var n_expr: AExpr is writable, noinit
        var n_then: nullable AExpr = null is writable
        var n_else: nullable AExpr = null is writable
end

# A `if` expression
class AIfexprExpr
        super AExpr
        var n_kwif: TKwif is writable, noinit
        var n_expr: AExpr is writable, noinit
        var n_kwthen: TKwthen is writable, noinit
        var n_then: AExpr is writable, noinit
        var n_kwelse: TKwelse is writable, noinit
        var n_else: AExpr is writable, noinit
end

# A `while` statement
class AWhileExpr
        super AExpr
        super ALabelable
        var n_kwwhile:  TKwwhile is writable, noinit
        var n_expr: AExpr is writable, noinit
        var n_kwdo: TKwdo is writable, noinit
        var n_block: nullable AExpr = null is writable
end

# A `loop` statement
class ALoopExpr
        super AExpr
        super ALabelable
        var n_kwloop: TKwloop is writable, noinit
        var n_block: nullable AExpr = null is writable
end

# A `for` statement
class AForExpr
        super AExpr
        super ALabelable
        var n_kwfor: TKwfor is writable, noinit
        var n_ids: ANodes[TId] = new ANodes[TId](self)
        var n_expr: AExpr is writable, noinit
        var n_kwdo: TKwdo is writable, noinit
        var n_block: nullable AExpr = null is writable
end

# An `assert` statement
class AAssertExpr
        super AExpr
        var n_kwassert: TKwassert is writable, noinit
        var n_id: nullable TId = null is writable
        var n_expr: AExpr is writable, noinit
        var n_else: nullable AExpr = null is writable
end

# Whatever is a simple assignment. eg `= something`
abstract class AAssignFormExpr
        super AExpr
        var n_assign: TAssign is writable, noinit
        var n_value: AExpr is writable, noinit
end

# Whatever is a combined assignment. eg `+= something`
abstract class AReassignFormExpr
        super AExpr
        var n_assign_op: AAssignOp is writable, noinit
        var n_value: AExpr is writable, noinit
end

# A `once` expression. eg `once x`
class AOnceExpr
        super AProxyExpr
        var n_kwonce: TKwonce is writable, noinit
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
        var n_expr: AExpr is writable, noinit
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
        var n_expr2: AExpr is writable, noinit
end

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

# A `or` expression 
class AOrExpr
        super ABoolExpr
        var n_expr: AExpr is writable, noinit
        var n_expr2: AExpr is writable, noinit
end

# A `and` expression
class AAndExpr
        super ABoolExpr
        var n_expr: AExpr is writable, noinit
        var n_expr2: AExpr is writable, noinit
end

# A `or else` expression
class AOrElseExpr
        super ABoolExpr
        var n_expr: AExpr is writable, noinit
        var n_expr2: AExpr is writable, noinit
end

# A `implies` expression
class AImpliesExpr
        super ABoolExpr
        var n_expr: AExpr is writable, noinit
        var n_expr2: AExpr is writable, noinit
end

# A `not` expression
class ANotExpr
        super ABoolExpr
        var n_kwnot: TKwnot is writable, noinit
        var n_expr: AExpr is writable, noinit
end

# A `==` expression
class AEqExpr
        super ABinopExpr
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
        var n_expr: AExpr is writable, noinit
        var n_type: AType is writable, noinit
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 AStarstarExpr
        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
        var n_minus: TMinus is writable, noinit
end

# An explicit instantiation. eg `new T`
class ANewExpr
        super AExpr
        var n_kwnew: TKwnew is writable, noinit
        var n_type: AType is writable, noinit

        # The name of the named-constructor, if any
        var n_id: nullable TId = null is writable
        var n_args: AExprs is writable, noinit
end

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

        # The receiver of the attribute
        var n_expr: AExpr is writable, noinit

        # The name of the attribute
        var n_id: TAttrid is writable, noinit

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
        var n_id: TId is writable, noinit

        # The arguments of the call
        var n_args: AExprs is writable, noinit
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
        var n_qualified: nullable AQualified = null is writable
        var n_kwsuper: TKwsuper is writable, noinit
        var n_args: AExprs is writable, noinit
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
        var n_kwinit: TKwinit is writable, noinit
        var n_args: AExprs is writable, noinit
end

# Whatever looks-like a call of the brackets `[]` operator.
abstract class ABraFormExpr
        super ASendExpr
        var n_args: AExprs is writable, noinit
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
        var n_id: TId is writable, noinit
end

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

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

# A literal range, open or closed
abstract class ARangeExpr
        super AExpr
        var n_expr: AExpr is writable, noinit
        var n_expr2: AExpr is writable, noinit
end

# A closed literal range. eg `[x..y]`
class ACrangeExpr
        super ARangeExpr
        var n_obra: TObra is writable, noinit
        var n_cbra: TCbra is writable, noinit
end

# An open literal range. eg `[x..y[`
class AOrangeExpr
        super ARangeExpr
        var n_obra: TObra is writable, noinit
        var n_cbra: TObra is writable, noinit
end

# A literal array. eg. `[x,y,z]`
class AArrayExpr
        super AExpr
        var n_exprs: AExprs is writable, noinit
end

# A read of `self` 
class ASelfExpr
        super AExpr
        var n_kwself: nullable TKwself is writable
end

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

# A `true` boolean literal constant
class ATrueExpr
        super ABoolExpr
        var n_kwtrue: TKwtrue is writable, noinit
end
# A `false` boolean literal constant
class AFalseExpr
        super ABoolExpr
        var n_kwfalse: TKwfalse is writable, noinit
end
# A `null` literal constant
class ANullExpr
        super AExpr
        var n_kwnull: TKwnull is writable, noinit
end
# An integer literal
class AIntExpr
        super AExpr
end
# An integer literal in decimal format
class ADecIntExpr
        super AIntExpr
        var n_number: TNumber is writable, noinit
end
# An integer literal in hexadecimal format
class AHexIntExpr
        super AIntExpr
        var n_hex_number: THexNumber is writable, noinit
end
# A float literal
class AFloatExpr
        super AExpr
        var n_float: TFloat is writable, noinit
end
# A character literal
class ACharExpr
        super AExpr
        var n_char: TChar is writable, noinit
end
# A string literal
abstract class AStringFormExpr
        super AExpr
        var n_string: Token is writable, noinit
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
        var n_exprs: ANodes[AExpr] = new ANodes[AExpr](self)
end

# A simple parenthesis. eg `(x)`
class AParExpr
        super AProxyExpr
        var n_opar: TOpar is writable, noinit
        var n_cpar: TCpar is writable, noinit
end

# Whatevej just contains (and mimic) an other expression
abstract class AProxyExpr
        super AExpr
        var n_expr: AExpr is writable, noinit
end

# A type cast. eg `x.as(T)`
class AAsCastExpr
        super AExpr
        var n_expr: AExpr is writable, noinit
        var n_kwas: TKwas is writable, noinit
        var n_opar: nullable TOpar = null is writable
        var n_type: AType is writable, noinit
        var n_cpar: nullable TCpar = null is writable
end

# A as-not-null cast. eg `x.as(not null)`
class AAsNotnullExpr
        super AExpr
        var n_expr: AExpr is writable, noinit
        var n_kwas: TKwas is writable, noinit
        var n_opar: nullable TOpar = null is writable
        var n_kwnot: TKwnot is writable, noinit
        var n_kwnull: TKwnull is writable, noinit
        var n_cpar: nullable TCpar = null is writable
end

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

# A elyspis notation used to pass an expression as it in a vararg parameter
class AVarargExpr
        super AExpr
        var n_expr: AExpr is writable, noinit
        var n_dotdotdot: TDotdotdot is writable, noinit
end

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


class ADebugTypeExpr
        super AExpr
        var n_kwdebug: TKwdebug is writable, noinit
        var n_kwtype: TKwtype is writable, noinit
        var n_expr: AExpr is writable, noinit
        var n_type: AType is writable, noinit
end

# A simple list of expressions
class AListExprs
        super AExprs
end

# A list of expressions enclosed in parentheses
class AParExprs
        super AExprs
        var n_opar: TOpar is writable, noinit
        var n_cpar: TCpar is writable, noinit
end

# A list of expressions enclosed in brackets
class ABraExprs
        super AExprs
        var n_obra: TObra is writable, noinit
        var n_cbra: TCbra is writable, noinit
end

# A complex assignment operator. eg `+=`
abstract class AAssignOp
        super Prod
end
class APlusAssignOp
        super AAssignOp
        var n_pluseq: TPluseq is writable, noinit
end
class AMinusAssignOp
        super AAssignOp
        var n_minuseq: TMinuseq is writable, noinit
end

class AModuleName
        super Prod
        var n_quad: nullable TQuad = null is writable
        var n_path: ANodes[TId] = new ANodes[TId](self)
        var n_id: TId is writable, noinit
end
class AInLanguage
        super Prod
        var n_kwin: TKwin is writable, noinit
        var n_string: TString is writable, noinit
end
class AExternCodeBlock
        super Prod
        var n_in_language: nullable AInLanguage = null is writable
        var n_extern_code_segment: TExternCodeSegment is writable, noinit
end
class AQualified
        super Prod
        var n_quad: nullable TQuad = null is writable
        var n_id: ANodes[TId] = new ANodes[TId](self)
        var n_classid: nullable TClassid = null is writable
end

# A documentation of a definition
# It contains the block of comments just above the declaration
class ADoc
        super Prod
        var n_comment: ANodes[TComment] = new ANodes[TComment](self)
end

class AAnnotations
        super Prod
        var n_at: nullable TAt = null is writable
        var n_opar: nullable TOpar = null is writable
        var n_items: ANodes[AAnnotation] = new ANodes[AAnnotation](self)
        var n_cpar: nullable TCpar = null is writable
end
class AAnnotation
        super Prod
        var n_doc: nullable ADoc = null is writable
        var n_kwredef: nullable TKwredef = null is writable
        var n_visibility: nullable AVisibility is writable
        var n_atid: AAtid is writable, noinit
        var n_opar: nullable TOpar = null is writable
        var n_args: ANodes[AAtArg] = new ANodes[AAtArg](self)
        var n_cpar: nullable TCpar = null is writable
end
abstract class AAtArg
        super Prod
end
class ATypeAtArg
        super AAtArg
        var n_type: AType is writable, noinit
end
class AExprAtArg
        super AAtArg
        var n_expr: AExpr is writable, noinit
end
class AAtAtArg
        super AAtArg
end
abstract class AAtid
        super Prod
        var n_id: Token is writable, noinit
end
class AIdAtid
        super AAtid
end
class AKwexternAtid
        super AAtid
end
class AKwimportAtid
        super AAtid
end
class AKwabstractAtid
        super AAtid
end

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