export declare const TokenType: {
    readonly LParen: "LParen";
    readonly RParen: "RParen";
    readonly LBracket: "LBracket";
    readonly RBracket: "RBracket";
    readonly LBrace: "LBrace";
    readonly RBrace: "RBrace";
    readonly Comma: "Comma";
    readonly Semi: "Semi";
    readonly Colon: "Colon";
    readonly Dot: "Dot";
    readonly QuestDot: "QuestDot";
    readonly DollarDot: "DollarDot";
    readonly Dollar: "Dollar";
    readonly DoubleDollar: "DoubleDollar";
    readonly TripleDollar: "TripleDollar";
    readonly QuadDollar: "QuadDollar";
    readonly Spread: "Spread";
    readonly Plus: "Plus";
    readonly Minus: "Minus";
    readonly Star: "Star";
    readonly StarStar: "StarStar";
    readonly Slash: "Slash";
    readonly Percent: "Percent";
    readonly PlusPlus: "PlusPlus";
    readonly MinusMinus: "MinusMinus";
    readonly Eq: "Eq";
    readonly PlusEq: "PlusEq";
    readonly MinusEq: "MinusEq";
    readonly StarEq: "StarEq";
    readonly SlashEq: "SlashEq";
    readonly EqEq: "EqEq";
    readonly EqEqEq: "EqEqEq";
    readonly BangEq: "BangEq";
    readonly BangEqEq: "BangEqEq";
    readonly Gt: "Gt";
    readonly GtEq: "GtEq";
    readonly Lt: "Lt";
    readonly LtEq: "LtEq";
    readonly AmpAmp: "AmpAmp";
    readonly PipePipe: "PipePipe";
    readonly Bang: "Bang";
    readonly Amp: "Amp";
    readonly Pipe: "Pipe";
    readonly Caret: "Caret";
    readonly Tilde: "Tilde";
    readonly QuestQuest: "QuestQuest";
    readonly Quest: "Quest";
    readonly Arrow: "Arrow";
    readonly Number: "Number";
    readonly BigInt: "BigInt";
    readonly String: "String";
    readonly True: "True";
    readonly False: "False";
    readonly Null: "Null";
    readonly Undefined: "Undefined";
    readonly RegexLiteral: "RegexLiteral";
    readonly TemplateStart: "TemplateStart";
    readonly TemplateChars: "TemplateChars";
    readonly TemplateExprStart: "TemplateExprStart";
    readonly TemplateEnd: "TemplateEnd";
    readonly In: "In";
    readonly New: "New";
    readonly Typeof: "Typeof";
    readonly Delete: "Delete";
    readonly Let: "Let";
    readonly Ident: "Ident";
    readonly EOF: "EOF";
};
export type TokenType = (typeof TokenType)[keyof typeof TokenType];
/**
 * Human-friendly display string for each token type, used in lexer/parser error
 * messages so users see `'('` instead of the internal `LParen` enum name. For
 * punctuation we quote the literal character(s); for value-bearing tokens
 * (identifiers, numbers, strings, …) we use a descriptive word so the message
 * still reads naturally when paired with `got 'foo'`. Keep in sync with the
 * `TokenType` declaration above.
 */
export declare const TOKEN_DISPLAY: Record<TokenType, string>;
/**
 * Format a token for the "but got X" half of an error message. For value-bearing
 * tokens (identifiers, numbers, strings) the actual lexeme is more useful than
 * the category name, so we render it as e.g. `an identifier 'foo'` or
 * `a number '42'`. For punctuation the display already *is* the lexeme, so the
 * `('${value}')` suffix would be redundant.
 */
export declare function formatActualToken(t: Token): string;
export type Token = {
    type: TokenType;
    value: string;
    pos: number;
    flags?: string;
};
export declare class LexError extends Error {
    readonly pos: number;
    constructor(message: string, pos: number);
}
export declare class Lexer {
    private pos;
    private readonly tokens;
    private tokenIdx;
    private lastTokenType;
    private braceDepth;
    private templateBraceDepths;
    private readonly src;
    constructor(src: string);
    peek(): Token;
    next(): Token;
    lookahead(offset: number): Token;
    expect(type: TokenType): Token;
    private pushToken;
    private tokenize;
    private emit;
    private static readonly LINE_TERMINATORS;
    private skipTrivia;
    private skipLineComment;
    private skipBlockComment;
    private isDigit;
    private isIdentStart;
    private isIdentPart;
    private readNumber;
    /**
     * Consume a run of digits, allowing single underscores between them as numeric
     * separators (1_000_000). Rejects leading, trailing, or doubled underscores.
     */
    private consumeDigitsWithSeparators;
    private readString;
    /**
     * Read a chunk of a template literal — characters between the previous boundary
     * (opening `, or `${...}`) and the next boundary (closing `, or `${`).
     *
     * Always emits a TemplateChars token (possibly empty) followed by either:
     *   - TemplateExprStart for `${`, then returns to caller (main lex loop resumes
     *     normal lexing inside the expression — the matching `}` re-enters this method)
     *   - TemplateEnd for closing backtick, then returns
     */
    private readTemplateChunk;
    private readRegex;
    private readIdent;
    private keywordToken;
}
//# sourceMappingURL=lexer.d.ts.map