var Keywords = map[string]TokenType{

	"await":      AwaitToken,
	"break":      BreakToken,
	"case":       CaseToken,
	"catch":      CatchToken,
	"class":      ClassToken,
	"const":      ConstToken,
	"continue":   ContinueToken,
	"debugger":   DebuggerToken,
	"default":    DefaultToken,
	"delete":     DeleteToken,
	"do":         DoToken,
	"else":       ElseToken,
	"enum":       EnumToken,
	"export":     ExportToken,
	"extends":    ExtendsToken,
	"false":      FalseToken,
	"finally":    FinallyToken,
	"for":        ForToken,
	"function":   FunctionToken,
	"if":         IfToken,
	"import":     ImportToken,
	"in":         InToken,
	"instanceof": InstanceofToken,
	"new":        NewToken,
	"null":       NullToken,
	"return":     ReturnToken,
	"super":      SuperToken,
	"switch":     SwitchToken,
	"this":       ThisToken,
	"throw":      ThrowToken,
	"true":       TrueToken,
	"try":        TryToken,
	"typeof":     TypeofToken,
	"var":        VarToken,
	"void":       VoidToken,
	"while":      WhileToken,
	"with":       WithToken,
	"yield":      YieldToken,

	"let":        LetToken,
	"static":     StaticToken,
	"implements": ImplementsToken,
	"interface":  InterfaceToken,
	"package":    PackageToken,
	"private":    PrivateToken,
	"protected":  ProtectedToken,
	"public":     PublicToken,

	"as":     AsToken,
	"async":  AsyncToken,
	"from":   FromToken,
	"get":    GetToken,
	"meta":   MetaToken,
	"of":     OfToken,
	"set":    SetToken,
	"target": TargetToken,
}

type AST struct {
	Comment   []byte // first comment in file
	BlockStmt        // module
}

type Alias struct {
	Name    []byte // can be nil
	Binding []byte // can be nil
}

type Arguments struct {
	List []IExpr
	Rest IExpr // can be nil
}

type ArrayExpr struct {
	List []Element
}

type ArrowFunc struct {
	Async  bool
	Params Params
	Body   BlockStmt
}

type BinaryExpr struct {
	Op   TokenType
	X, Y IExpr
}

type BindingArray struct {
	List []BindingElement
	Rest IBinding // can be nil
}

type BindingElement struct {
	Binding IBinding // can be nil (in case of ellision)
	Default IExpr    // can be nil
}

type BindingObject struct {
	List []BindingObjectItem
	Rest *Var // can be nil
}

type BindingObjectItem struct {
	Key   *PropertyName // can be nil
	Value BindingElement
}

type BlockStmt struct {
	List []IStmt
	Scope
}

type BranchStmt struct {
	Type  TokenType
	Label []byte // can be nil
}

type CallExpr struct {
	X    IExpr
	Args Arguments
}

type CaseClause struct {
	TokenType
	Cond IExpr // can be nil
	List []IStmt
}

type ClassDecl struct {
	Name    *Var  // can be nil
	Extends IExpr // can be nil
	Methods []MethodDecl
}

type CondExpr struct {
	Cond, X, Y IExpr
}

type DebuggerStmt struct {
}

type DeclType uint16

const (
	NoDecl       DeclType = iota // undeclared variables
	VariableDecl                 // var
	FunctionDecl                 // function
	LexicalDecl                  // let, const, class
	ArgumentDecl                 // function, method, and catch statement arguments
	ExprDecl                     // function expression name or class expression name
)

type DoWhileStmt struct {
	Cond IExpr
	Body IStmt
}

type DotExpr struct {
	X    IExpr
	Y    LiteralExpr
	Prec OpPrec
}

type Element struct {
	Value  IExpr // can be nil
	Spread bool
}

type EmptyStmt struct {
}

type ExportStmt struct {
	List    []Alias
	Module  []byte // can be nil
	Default bool
	Decl    IExpr
}

type ExprStmt struct {
	Value IExpr
}

type ForInStmt struct {
	Init  IExpr
	Value IExpr
	Body  BlockStmt
}

type ForOfStmt struct {
	Await bool
	Init  IExpr
	Value IExpr
	Body  BlockStmt
}

type ForStmt struct {
	Init IExpr // can be nil
	Cond IExpr // can be nil
	Post IExpr // can be nil
	Body BlockStmt
}

type FuncDecl struct {
	Async     bool
	Generator bool
	Name      *Var // can be nil
	Params    Params
	Body      BlockStmt
}

type GroupExpr struct {
	X IExpr
}

type IBinding interface {
	String() string
	// contains filtered or unexported methods
}

type IExpr interface {
	String() string
	// contains filtered or unexported methods
}

type IStmt interface {
	String() string
	// contains filtered or unexported methods
}

type IfStmt struct {
	Cond IExpr
	Body IStmt
	Else IStmt // can be nil
}

type ImportMetaExpr struct {
}

type ImportStmt struct {
	List    []Alias
	Default []byte // can be nil
	Module  []byte
}

type IndexExpr struct {
	X     IExpr
	Index IExpr
	Prec  OpPrec
}

type LabelledStmt struct {
	Label []byte
	Value IStmt
}

type Lexer struct {
	// contains filtered or unexported fields
}

type LiteralExpr struct {
	TokenType
	Data []byte
}

type MethodDecl struct {
	Static    bool
	Async     bool
	Generator bool
	Get       bool
	Set       bool
	Name      PropertyName
	Params    Params
	Body      BlockStmt
}

type NewExpr struct {
	X    IExpr
	Args *Arguments // can be nil
}

type NewTargetExpr struct {
}

type ObjectExpr struct {
	List []Property
}

type OpPrec int

const (
	OpExpr     OpPrec = iota // a,b
	OpAssign                 // a?b:c, yield x, ()=>x, async ()=>x, a=b, a+=b, ...
	OpCoalesce               // a??b
	OpOr                     // a||b
	OpAnd                    // a&&b
	OpBitOr                  // a|b
	OpBitXor                 // a^b
	OpBitAnd                 // a&b
	OpEquals                 // a==b, a!=b, a===b, a!==b
	OpCompare                // a<b, a>b, a<=b, a>=b, a instanceof b, a in b
	OpShift                  // a<<b, a>>b, a>>>b
	OpAdd                    // a+b, a-b
	OpMul                    // a*b, a/b, a%b
	OpExp                    // a**b
	OpUnary                  // ++x, --x, delete x, void x, typeof x, +x, -x, ~x, !x, await x
	OpUpdate                 // x++, x--
	OpLHS                    // CallExpr/OptChainExpr or NewExpr
	OpCall                   // a?.b, a(b), super(a), import(a)
	OpNew                    // new a
	OpMember                 // a[b], a.b, a`b`, super[x], super.x, new.target, import.meta, new a(b)
	OpPrimary                // literal, function, class, parenthesized
)

type OptChainExpr struct {
	X IExpr
	Y IExpr // can be CallExpr, IndexExpr, LiteralExpr, or TemplateExpr
}

type Params struct {
	List []BindingElement
	Rest IBinding // can be nil
}

type Parser struct {
	// contains filtered or unexported fields
}

type Property struct {
	// either Name or Spread are set. When Spread is set then Value is AssignmentExpression
	// if Init is set then Value is IdentifierReference, otherwise it can also be MethodDefinition
	Name   *PropertyName // can be nil
	Spread bool
	Value  IExpr
	Init   IExpr // can be nil
}

type PropertyName struct {
	Literal  LiteralExpr
	Computed IExpr // can be nil
}

type ReturnStmt struct {
	Value IExpr // can be nil
}

type Scope struct {
	Parent, Func   *Scope   // Parent is nil for global scope, Parent equals Func for function scope
	Declared       VarArray // Link in Var are always nil
	Undeclared     VarArray
	NumVarDecls    uint16 // number of variable declaration statements in a function scope
	NumArguments   uint16 // offset into Undeclared to mark variables used in arguments
	IsGlobalOrFunc bool
	HasWith        bool
}

type SwitchStmt struct {
	Init IExpr
	List []CaseClause
}

type TemplateExpr struct {
	Tag  IExpr // can be nil
	List []TemplatePart
	Tail []byte
	Prec OpPrec
}

type TemplatePart struct {
	Value []byte
	Expr  IExpr
}

type ThrowStmt struct {
	Value IExpr
}

type TokenType uint16 // from LSB to MSB: 8 bits for tokens per category, 1 bit for numeric, 1 bit for punctuator, 1 bit for operator, 1 bit for identifier, 4 bits unused

const (
	ErrorToken TokenType = iota // extra token when errors occur
	WhitespaceToken
	LineTerminatorToken // \r \n \r\n
	CommentToken
	CommentLineTerminatorToken
	StringToken
	TemplateToken
	TemplateStartToken
	TemplateMiddleToken
	TemplateEndToken
	RegExpToken
)

const (
	NumericToken TokenType = 0x0100 + iota
	DecimalToken
	BinaryToken
	OctalToken
	HexadecimalToken
	BigIntToken
)

const (
	PunctuatorToken   TokenType = 0x0200 + iota
	OpenBraceToken              // {
	CloseBraceToken             // }
	OpenParenToken              // (
	CloseParenToken             // )
	OpenBracketToken            // [
	CloseBracketToken           // ]
	DotToken                    // .
	SemicolonToken              // ;
	CommaToken                  // ,
	QuestionToken               // ?
	ColonToken                  // :
	ArrowToken                  // =>
	EllipsisToken               // ...
)

const (
	OperatorToken TokenType = 0x0600 + iota
	EqToken                 // =
	EqEqToken               // ==
	EqEqEqToken             // ===
	NotToken                // !
	NotEqToken              // !=
	NotEqEqToken            // !==
	LtToken                 // <
	LtEqToken               // <=
	LtLtToken               // <<
	LtLtEqToken             // <<=
	GtToken                 // >
	GtEqToken               // >=
	GtGtToken               // >>
	GtGtEqToken             // >>=
	GtGtGtToken             // >>>
	GtGtGtEqToken           // >>>=
	AddToken                // +
	AddEqToken              // +=
	IncrToken               // ++
	SubToken                // -
	SubEqToken              // -=
	DecrToken               // --
	MulToken                // *
	MulEqToken              // *=
	ExpToken                // **
	ExpEqToken              // **=
	DivToken                // /
	DivEqToken              // /=
	ModToken                // %
	ModEqToken              // %=
	BitAndToken             // &
	BitOrToken              // |
	BitXorToken             // ^
	BitNotToken             // ~
	BitAndEqToken           // &=
	BitOrEqToken            // |=
	BitXorEqToken           // ^=
	AndToken                // &&
	OrToken                 // ||
	NullishToken            // ??
	OptChainToken           // ?.

	// unused in lexer
	PosToken      // +a
	NegToken      // -a
	PreIncrToken  // ++a
	PreDecrToken  // --a
	PostIncrToken // a++
	PostDecrToken // a--
)

const (
	ReservedToken TokenType = 0x0800 + iota
	AwaitToken
	BreakToken
	CaseToken
	CatchToken
	ClassToken
	ConstToken
	ContinueToken
	DebuggerToken
	DefaultToken
	DeleteToken
	DoToken
	ElseToken
	EnumToken
	ExportToken
	ExtendsToken
	FalseToken
	FinallyToken
	ForToken
	FunctionToken
	IfToken
	ImportToken
	InToken
	InstanceofToken
	NewToken
	NullToken
	ReturnToken
	SuperToken
	SwitchToken
	ThisToken
	ThrowToken
	TrueToken
	TryToken
	TypeofToken
	YieldToken
	VarToken
	VoidToken
	WhileToken
	WithToken
)

const (
	IdentifierToken TokenType = 0x1000 + iota
	AsToken
	AsyncToken
	FromToken
	GetToken
	ImplementsToken
	InterfaceToken
	LetToken
	MetaToken
	OfToken
	PackageToken
	PrivateToken
	ProtectedToken
	PublicToken
	SetToken
	StaticToken
	TargetToken
)

type TryStmt struct {
	Body    BlockStmt
	Binding IBinding   // can be nil
	Catch   *BlockStmt // can be nil
	Finally *BlockStmt // can be nil
}

type UnaryExpr struct {
	Op TokenType
	X  IExpr
}

type Var struct {
	Decl DeclType
	Data []byte
	Link *Var // is set when merging variable uses, as in:  {a} {var a}  where the first lins to the second
	Uses uint16
}

type VarArray []*Var

type VarDecl struct {
	TokenType
	List []BindingElement
}

type VarsByUses VarArray

type WhileStmt struct {
	Cond IExpr
	Body IStmt
}

type WithStmt struct {
	Cond IExpr
	Body IStmt
}

type YieldExpr struct {
	Generator bool
	X         IExpr // can be nil
}