import { BaseTokenReader } from './BaseTokenReader';
import { Lexeme } from '../models/Lexeme';
/**
 * Reads SQL parameter tokens (@param, :param, $param, ?, ${param})
 */
export declare class ParameterTokenReader extends BaseTokenReader {
    constructor(input: string);
    /**
     * Try to read a parameter token
     */
    tryRead(previous: Lexeme | null): Lexeme | null;
    /**
     * Check if we're in an array slice context where : should be treated as an operator
     * Look backwards for an opening bracket that suggests array access
     */
    private isInArraySliceContext;
    /**
     * Check if the current position starts a PostgreSQL dollar-quoted string
     * Patterns: $$ or $tag$
     */
    private isDollarQuotedString;
    /**
     * Check if character is alphanumeric (letter or digit)
     */
    private isAlphanumeric;
}