/**
 * OpenQASM 2.0 Token Definitions and Utilities
 *
 * This module defines the token types used in OpenQASM 2.0 syntax. OpenQASM 2.0
 * has a simpler token set compared to 3.0, focusing on basic quantum operations
 * and classical registers without advanced control flow or data types.
 *
 * Key differences from OpenQASM 3.0:
 * - Limited to `qreg` and `creg` declarations (no advanced types)
 * - No control flow tokens (if/else/for/while)
 * - No subroutine or function definitions
 * - Simpler expression and operator support
 *
 * @module
 *
 * @example OpenQASM 2.0 token usage
 * ```typescript
 * import { lookup, Token } from './qasm2/token';
 *
 * console.log(lookup('qreg'));    // Token.QReg
 * console.log(lookup('barrier')); // Token.Barrier
 * console.log(lookup('measure')); // Token.Measure
 * ```
 */
/**
 * Enumeration of OpenQASM 2.0 token types.
 *
 * This simplified token set reflects OpenQASM 2.0's focus on basic quantum
 * circuit description without the advanced features of version 3.0.
 */
declare enum Token {
    Illegal = 0,
    EndOfFile = 1,
    Real = 2,
    NNInteger = 3,
    Id = 4,
    OpenQASM = 5,
    Semicolon = 6,
    Comma = 7,
    LParen = 8,
    LSParen = 9,
    LCParen = 10,
    RParen = 11,
    RSParen = 12,
    RCParen = 13,
    Arrow = 14,
    Equals = 15,
    Plus = 16,
    Minus = 17,
    Times = 18,
    Divide = 19,
    Power = 20,
    Sin = 21,
    Cos = 22,
    Tan = 23,
    Exp = 24,
    Ln = 25,
    Sqrt = 26,
    Pi = 27,
    QReg = 28,
    CReg = 29,
    Barrier = 30,
    Gate = 31,
    Measure = 32,
    Reset = 33,
    Include = 34,
    If = 35,
    String = 36,
    Opaque = 37
}
/**
 * Returns the token that represents a given string.
 * @param ident - The string.
 * @return The corresponding token.
 */
declare function lookup(ident: string): Token;
/**
 * Returns the string representation of a token.
 * @param tokens - The token.
 * @return The string representation of the token.
 */
declare function inverseLookup(token: Token): string;
/**
 * Determines whether a token denotes a parameter.
 * @param tokens - The token.
 * @return Whether the token does NOT denote a parameter.
 */
declare function notParam(token: Token): boolean;
export { Token, notParam, lookup, inverseLookup };