oxc_parser/lexer/

kind.rs

//! ECMAScript Token Kinds

use std::fmt::{self, Display};

use oxc_data_structures::fieldless_enum;

// `fieldless_enum!` macro provides `Kind::VARIANTS` constant listing all variants
fieldless_enum! {
    /// Lexer token kind
    ///
    /// Exported for other oxc crates to use. You generally don't need to use this directly.
    #[derive(Debug, Default, Clone, Copy, Eq, PartialEq)]
    #[repr(u8)]
    #[non_exhaustive]
    pub enum Kind {
        #[default]
        Eof = 0,
        Undetermined,
        Skip, // Whitespace, line breaks, comments
        // 12.5 Hashbang Comments
        HashbangComment,
        // 12.7.1 identifier
        Ident,
        // 12.7.2 keyword
        Await,
        Break,
        Case,
        Catch,
        Class,
        Const,
        Continue,
        Debugger,
        Default,
        Delete,
        Do,
        Else,
        Enum,
        Export,
        Extends,
        Finally,
        For,
        Function,
        If,
        Import,
        In,
        Instanceof,
        New,
        Return,
        Super,
        Switch,
        This,
        Throw,
        Try,
        Typeof,
        Var,
        Void,
        While,
        With,
        // Contextual Keywords
        Async,
        From,
        Get,
        Meta, // import.meta
        Of,
        Set,
        Target,   // new.target
        Accessor, // keyword from https://github.com/tc39/proposal-decorators
        Source,   // import.source https://github.com/tc39/proposal-source-phase-imports
        Defer,    // import.defer https://github.com/tc39/proposal-defer-import-eval
        // TypeScript Contextual Keywords
        Abstract,
        As,
        Asserts,
        Assert,
        Any,
        Boolean,
        Constructor,
        Declare,
        Infer,
        Intrinsic,
        Is,
        KeyOf,
        Module,
        Namespace,
        Never,
        Out,
        Readonly,
        Require,
        Number, // the "number" keyword for TypeScript
        Object,
        Satisfies,
        String, // the "string" keyword for TypeScript
        Symbol,
        Type,
        Undefined,
        Unique,
        Using,
        Unknown,
        Global,
        BigInt, // the "bigint" keyword for TypeScript
        Override,
        // Future keywords (strict mode reserved words)
        Implements,
        Interface,
        Let,
        Package,
        Private,
        Protected,
        Public,
        Static,
        Yield,
        // 12.9.1 Null Literals
        // 12.9.2 Boolean Literals
        // Moved here to make all keywords contiguous for range check optimization
        True,
        False,
        Null,
        // 12.8 punctuators
        Amp, // &
        Amp2,
        Amp2Eq,
        AmpEq,
        Bang, // !
        Caret,
        CaretEq,
        Colon,
        Comma,
        Dot,
        Dot3, // ...
        Eq,
        Eq2,
        Eq3,
        GtEq, // >=
        LAngle,
        LBrack,
        LCurly,
        LParen,
        LtEq, // <=
        Minus,
        Minus2,
        MinusEq,
        Neq,
        Neq2,
        Percent,
        PercentEq,
        Pipe,
        Pipe2,
        Pipe2Eq,
        PipeEq,
        Plus,
        Plus2,
        PlusEq,
        Question,
        Question2,
        Question2Eq,
        QuestionDot,
        RAngle,
        RBrack,
        RCurly,
        RParen,
        Semicolon,
        ShiftLeft,     // <<
        ShiftLeftEq,   // <<=
        ShiftRight,    // >>
        ShiftRight3,   // >>>
        ShiftRight3Eq, // >>>=
        ShiftRightEq,  // >>=
        Slash,
        SlashEq,
        Star,
        Star2,
        Star2Eq,
        StarEq,
        Tilde,
        // arrow function
        Arrow,
        // 12.9.3 Numeric Literals
        Decimal,
        Float,
        Binary,
        Octal,
        Hex,
        // for `1e10`, `1e+10`
        PositiveExponential,
        // for `1e-10`
        NegativeExponential,
        // BigInt Literals (numeric literals with 'n' suffix)
        DecimalBigInt,
        BinaryBigInt,
        OctalBigInt,
        HexBigInt,
        // 12.9.4 String Literals
        /// String Type
        Str,
        // 12.9.5 Regular Expression Literals
        RegExp,
        // 12.9.6 Template Literal
        NoSubstitutionTemplate,
        TemplateHead,
        TemplateMiddle,
        TemplateTail,
        // es2022 Private Identifier
        PrivateIdentifier,
        // JSX
        JSXText,
        // Decorator
        At,
    }
}

#[allow(clippy::enum_glob_use, clippy::allow_attributes)]
use Kind::*;

impl Kind {
    #[inline]
    pub const fn is_eof(self) -> bool {
        matches!(self, Eof)
    }

    #[rustfmt::skip]
    #[inline]
    pub const fn is_number(self) -> bool {
        matches!(
            self,
            Decimal | Float | Binary | Octal | Hex | PositiveExponential | NegativeExponential
            | DecimalBigInt | BinaryBigInt | OctalBigInt | HexBigInt
        )
    }

    #[inline] // Inline into `read_non_decimal` - see comment there as to why
    pub fn matches_number_byte(self, b: u8) -> bool {
        match self {
            Decimal => b.is_ascii_digit(),
            Binary => matches!(b, b'0'..=b'1'),
            Octal => matches!(b, b'0'..=b'7'),
            Hex => b.is_ascii_hexdigit(),
            _ => unreachable!(),
        }
    }

    /// [Identifiers](https://tc39.es/ecma262/#sec-identifiers)
    /// `IdentifierReference`
    #[inline]
    pub const fn is_identifier_reference(
        self,
        is_yield_context: bool,
        is_await_context: bool,
    ) -> bool {
        self.is_identifier()
            || (!is_yield_context && matches!(self, Yield))
            || (!is_await_context && matches!(self, Await))
    }

    /// `BindingIdentifier`
    #[inline]
    pub const fn is_binding_identifier(self) -> bool {
        self.is_identifier() || matches!(self, Yield | Await)
    }

    /// `LabelIdentifier`
    #[inline]
    pub const fn is_label_identifier(self, is_yield_context: bool, is_await_context: bool) -> bool {
        self.is_identifier()
            || (!is_yield_context && matches!(self, Yield))
            || (!is_await_context && matches!(self, Await))
    }

    /// Identifier
    /// `IdentifierName` but not `ReservedWord`
    #[inline]
    pub const fn is_identifier(self) -> bool {
        self.is_identifier_name() && !self.is_reserved_keyword()
    }

    /// TypeScript Identifier
    ///
    /// <https://github.com/microsoft/TypeScript/blob/15392346d05045742e653eab5c87538ff2a3c863/src/compiler/parser.ts#L2316-L2335>
    #[inline]
    pub const fn is_ts_identifier(self, is_yield_context: bool, is_await_context: bool) -> bool {
        self.is_identifier_reference(is_yield_context, is_await_context)
            && !self.is_strict_mode_contextual_keyword()
            && !self.is_contextual_keyword()
    }

    /// `IdentifierName`
    /// All identifier names are either `Ident` or keywords (Await..=Null in the enum).
    #[inline]
    pub const fn is_identifier_name(self) -> bool {
        matches!(self, Ident) || matches!(self as u8, x if x >= Await as u8 && x <= Null as u8)
    }

    /// Check the succeeding token of a `let` keyword.
    ///
    /// ```javascript
    /// let { a, b } = c, let [a, b] = c, let ident
    /// ```
    #[inline]
    pub const fn is_after_let(self) -> bool {
        !matches!(self, In | Instanceof)
            && (matches!(self, LCurly | LBrack | Ident) || self.is_any_keyword())
    }

    /// Section 13.2.4 Literals
    /// Literal :
    ///     `NullLiteral`
    ///     `BooleanLiteral`
    ///     `NumericLiteral`
    ///     `StringLiteral`
    #[inline]
    pub const fn is_literal(self) -> bool {
        matches!(self, Null | True | False | Str | RegExp) || self.is_number()
    }

    #[inline]
    pub const fn is_after_await_or_yield(self) -> bool {
        !self.is_binary_operator() && (self.is_literal() || self.is_identifier_name())
    }

    /// Section 13.2.6 Object Initializer
    /// `LiteralPropertyName` :
    ///     `IdentifierName`
    ///     `StringLiteral`
    ///     `NumericLiteral`
    #[inline]
    pub const fn is_literal_property_name(self) -> bool {
        self.is_identifier_name() || matches!(self, Str) || self.is_number()
    }

    #[inline]
    pub const fn is_identifier_or_keyword(self) -> bool {
        self.is_literal_property_name() || matches!(self, PrivateIdentifier)
    }

    #[rustfmt::skip]
    #[inline]
    pub const fn is_assignment_operator(self) -> bool {
        matches!(
            self,
            Eq | PlusEq | MinusEq | StarEq | SlashEq | PercentEq | ShiftLeftEq | ShiftRightEq
            | ShiftRight3Eq | Pipe2Eq | Amp2Eq | PipeEq | CaretEq | AmpEq | Question2Eq | Star2Eq
        )
    }

    #[rustfmt::skip]
    #[inline]
    pub const fn is_binary_operator(self) -> bool {
        matches!(
            self,
            Eq2 | Neq | Eq3 | Neq2 | LAngle | LtEq | RAngle | GtEq | ShiftLeft | ShiftRight | ShiftRight3
            | Plus | Minus | Star | Slash | Percent | Pipe | Caret | Amp | In | Instanceof | Star2
        )
    }

    #[inline]
    pub const fn is_logical_operator(self) -> bool {
        matches!(self, Pipe2 | Amp2 | Question2)
    }

    #[inline]
    pub const fn is_unary_operator(self) -> bool {
        matches!(self, Minus | Plus | Bang | Tilde | Typeof | Void | Delete)
    }

    #[inline]
    pub const fn is_update_operator(self) -> bool {
        matches!(self, Plus2 | Minus2)
    }

    /// [Keywords and Reserved Words](https://tc39.es/ecma262/#sec-keywords-and-reserved-words)
    #[inline]
    pub const fn is_any_keyword(self) -> bool {
        // Note: `is_future_reserved_keyword` is a subset of `is_strict_mode_contextual_keyword`,
        // so the last arm is redundant. We include it anyway so each spec category is represented:
        // - Reserved words: https://tc39.es/ecma262/#prod-ReservedWord
        // - Contextual keywords: https://tc39.es/ecma262/#sec-keywords-and-reserved-words
        // - Strict mode reserved words: https://tc39.es/ecma262/#sec-strict-mode-of-ecmascript
        // - Future reserved words: https://tc39.es/ecma262/#sec-future-reserved-words
        // The compiler optimizes all four calls into a single range check (2 instructions total),
        // so keeping `is_future_reserved_keyword` has no performance impact.
        self.is_reserved_keyword()
            || self.is_contextual_keyword()
            || self.is_strict_mode_contextual_keyword()
            || self.is_future_reserved_keyword()
    }

    #[rustfmt::skip]
    #[inline]
    pub const fn is_reserved_keyword(self) -> bool {
        matches!(
            self,
            Await | Break | Case | Catch | Class | Const | Continue | Debugger | Default
            | Delete | Do | Else | Enum | Export | Extends | False | Finally | For | Function | If
            | Import | In | Instanceof | New | Null | Return | Super | Switch | This | Throw
            | True | Try | Typeof | Var | Void | While | With | Yield
        )
    }

    #[rustfmt::skip]
    #[inline]
    pub const fn is_strict_mode_contextual_keyword(self) -> bool {
        matches!(self, Let | Static | Implements | Interface | Package | Private | Protected | Public)
    }

    #[rustfmt::skip]
    #[inline]
    pub const fn is_contextual_keyword(self) -> bool {
        matches!(
            self,
            Async | From | Get | Meta | Of | Set | Target | Accessor | Abstract | As | Asserts | Assert
            | Any | Boolean | Constructor | Declare | Infer | Intrinsic | Is | KeyOf | Module | Namespace
            | Never | Out | Readonly | Require | Number | Object | Satisfies | String | Symbol | Type
            | Undefined | Unique | Unknown | Using | Global | BigInt | Override | Source | Defer
        )
    }

    #[rustfmt::skip]
    #[inline]
    pub const fn is_future_reserved_keyword(self) -> bool {
        matches!(self, Implements | Interface | Package | Private | Protected | Public | Static)
    }

    #[inline]
    pub const fn is_template_start_of_tagged_template(self) -> bool {
        matches!(self, NoSubstitutionTemplate | TemplateHead)
    }

    #[rustfmt::skip]
    #[inline]
    pub const fn is_modifier_kind(self) -> bool {
        matches!(
            self,
            Abstract | Accessor | Async | Const | Declare
            | In | Out | Public | Private | Protected | Readonly | Static | Override
            | Default | Export
        )
    }

    #[inline]
    pub const fn is_binding_identifier_or_private_identifier_or_pattern(self) -> bool {
        matches!(self, LCurly | LBrack | PrivateIdentifier) || self.is_binding_identifier()
    }

    #[cold]
    pub fn match_keyword(s: &str) -> Self {
        let len = s.len();
        // SAFETY: Already checked `len <= 1`.
        if len <= 1 || len >= 12 || !unsafe { s.as_bytes().get_unchecked(0) }.is_ascii_lowercase() {
            return Ident;
        }
        Self::match_keyword_impl(s)
    }

    fn match_keyword_impl(s: &str) -> Self {
        match s {
            "as" => As,
            "do" => Do,
            "if" => If,
            "in" => In,
            "is" => Is,
            "of" => Of,

            "any" => Any,
            "for" => For,
            "get" => Get,
            "let" => Let,
            "new" => New,
            "out" => Out,
            "set" => Set,
            "try" => Try,
            "var" => Var,

            "case" => Case,
            "else" => Else,
            "enum" => Enum,
            "from" => From,
            "meta" => Meta,
            "null" => Null,
            "this" => This,
            "true" => True,
            "type" => Type,
            "void" => Void,
            "with" => With,

            "async" => Async,
            "await" => Await,
            "break" => Break,
            "catch" => Catch,
            "class" => Class,
            "const" => Const,
            "false" => False,
            "infer" => Infer,
            "keyof" => KeyOf,
            "never" => Never,
            "super" => Super,
            "throw" => Throw,
            "using" => Using,
            "while" => While,
            "yield" => Yield,
            "defer" => Defer,

            "assert" => Assert,
            "bigint" => BigInt,
            "delete" => Delete,
            "export" => Export,
            "global" => Global,
            "import" => Import,
            "module" => Module,
            "number" => Number,
            "object" => Object,
            "public" => Public,
            "return" => Return,
            "static" => Static,
            "string" => String,
            "switch" => Switch,
            "symbol" => Symbol,
            "target" => Target,
            "typeof" => Typeof,
            "unique" => Unique,
            "source" => Source,

            "asserts" => Asserts,
            "boolean" => Boolean,
            "declare" => Declare,
            "default" => Default,
            "extends" => Extends,
            "finally" => Finally,
            "package" => Package,
            "private" => Private,
            "require" => Require,
            "unknown" => Unknown,

            "abstract" => Abstract,
            "accessor" => Accessor,
            "continue" => Continue,
            "debugger" => Debugger,
            "function" => Function,
            "override" => Override,
            "readonly" => Readonly,

            "interface" => Interface,
            "intrinsic" => Intrinsic,
            "namespace" => Namespace,
            "protected" => Protected,
            "satisfies" => Satisfies,
            "undefined" => Undefined,

            "implements" => Implements,
            "instanceof" => Instanceof,

            "constructor" => Constructor,
            _ => Ident,
        }
    }

    pub fn to_str(self) -> &'static str {
        #[expect(clippy::match_same_arms)]
        match self {
            Undetermined => "Unknown",
            Eof => "EOF",
            Skip => "Skipped",
            HashbangComment => "#!",
            Ident => "Identifier",
            Await => "await",
            Break => "break",
            Case => "case",
            Catch => "catch",
            Class => "class",
            Const => "const",
            Continue => "continue",
            Debugger => "debugger",
            Default => "default",
            Delete => "delete",
            Do => "do",
            Else => "else",
            Enum => "enum",
            Export => "export",
            Extends => "extends",
            Finally => "finally",
            For => "for",
            Function => "function",
            Using => "using",
            If => "if",
            Import => "import",
            In => "in",
            Instanceof => "instanceof",
            New => "new",
            Return => "return",
            Super => "super",
            Switch => "switch",
            This => "this",
            Throw => "throw",
            Try => "try",
            Typeof => "typeof",
            Var => "var",
            Void => "void",
            While => "while",
            With => "with",
            As => "as",
            Async => "async",
            From => "from",
            Get => "get",
            Meta => "meta",
            Of => "of",
            Set => "set",
            Asserts => "asserts",
            Accessor => "accessor",
            Abstract => "abstract",
            Readonly => "readonly",
            Declare => "declare",
            Override => "override",
            Type => "type",
            Target => "target",
            Source => "source",
            Defer => "defer",
            Implements => "implements",
            Interface => "interface",
            Package => "package",
            Private => "private",
            Protected => "protected",
            Public => "public",
            Static => "static",
            Let => "let",
            Yield => "yield",
            Amp => "&",
            Amp2 => "&&",
            Amp2Eq => "&&=",
            AmpEq => "&=",
            Bang => "!",
            Caret => "^",
            CaretEq => "^=",
            Colon => ":",
            Comma => ",",
            Dot => ".",
            Dot3 => "...",
            Eq => "=",
            Eq2 => "==",
            Eq3 => "===",
            GtEq => ">=",
            LAngle => "<",
            LBrack => "[",
            LCurly => "{",
            LParen => "(",
            LtEq => "<=",
            Minus => "-",
            Minus2 => "--",
            MinusEq => "-=",
            Neq => "!=",
            Neq2 => "!==",
            Percent => "%",
            PercentEq => "%=",
            Pipe => "|",
            Pipe2 => "||",
            Pipe2Eq => "||=",
            PipeEq => "|=",
            Plus => "+",
            Plus2 => "++",
            PlusEq => "+=",
            Question => "?",
            Question2 => "??",
            Question2Eq => "??=",
            QuestionDot => "?.",
            RAngle => ">",
            RBrack => "]",
            RCurly => "}",
            RParen => ")",
            Semicolon => ";",
            ShiftLeft => "<<",
            ShiftLeftEq => "<<=",
            ShiftRight => ">>",
            ShiftRight3 => ">>>",
            ShiftRight3Eq => ">>>=",
            ShiftRightEq => ">>=",
            Slash => "/",
            SlashEq => "/=",
            Star => "*",
            Star2 => "**",
            Star2Eq => "**=",
            StarEq => "*=",
            Tilde => "~",
            Arrow => "=>",
            Null => "null",
            True => "true",
            False => "false",
            Decimal => "decimal",
            Float | PositiveExponential | NegativeExponential => "float",
            Binary => "binary",
            Octal => "octal",
            Hex => "hex",
            DecimalBigInt => "decimal bigint",
            BinaryBigInt => "binary bigint",
            OctalBigInt => "octal bigint",
            HexBigInt => "hex bigint",
            Str | String => "string",
            RegExp => "/regexp/",
            NoSubstitutionTemplate => "${}",
            TemplateHead => "${",
            TemplateMiddle => "${expr}",
            TemplateTail => "}",
            PrivateIdentifier => "#identifier",
            JSXText => "jsx",
            At => "@",
            Assert => "assert",
            Any => "any",
            Boolean => "boolean",
            Constructor => "constructor",
            Infer => "infer",
            Intrinsic => "intrinsic",
            Is => "is",
            KeyOf => "keyof",
            Module => "module",
            Namespace => "namaespace",
            Never => "never",
            Out => "out",
            Require => "require",
            Number => "number",
            Object => "object",
            Satisfies => "satisfies",
            Symbol => "symbol",
            Undefined => "undefined",
            Unique => "unique",
            Unknown => "unknown",
            Global => "global",
            BigInt => "bigint",
        }
    }
}

impl Display for Kind {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        self.to_str().fmt(f)
    }
}