import Token from './Token';
/**
 * The lexer is responsible for reading in source code of the dsl and turn it into a list of meaningful tokens.
 */
export default class Lexer {
    private static readonly singleCharTokens;
    private static readonly keywords;
    /**
     * Checks if the given symbol is a digit from 0-9.
     *
     * @param symbol character to check
     * @private
     */
    private static isDigit;
    /**
     * Checks if the given symbol is an alphabetic lower- or uppercase value.
     *
     * @param symbol character to check
     * @private
     */
    private static isAlpha;
    /**
     * Checks if the given symbol is either a digit or alphabetic.
     *
     * @param symbol character to check
     * @private
     */
    private static isAlphaNumeric;
    private readonly tokens;
    private readonly source;
    private readonly offset;
    private start;
    private current;
    /**
     * Creates a new lexer instance for a given string of source code
     *
     * @param source source code
     * @param offset index offset into the source code
     */
    constructor(source: string, offset?: number);
    /**
     * Scans the source code and turns it into a list of tokens.
     */
    scan(): Token[];
    /**
     * Scans a single token on the current index.
     * @private
     */
    private scanToken;
    /**
     * Should the lexer come to a single quote char, it interprets as a string the next symbols until the next quote.
     * @private
     */
    private handleString;
    /**
     * Scans a number token.
     * @private
     */
    private handleNumber;
    /**
     * Scans an identifier token.
     * @private
     */
    private handleIdentifier;
    /**
     * Checks if the lexer is done scanning.
     * @private
     */
    private isAtEnd;
    /**
     * Consume the current symbol.
     * @private
     */
    private advance;
    /**
     * Consume the current symbol if it matches a given character, else return false.
     * @param expected expected character
     * @private
     */
    private match;
    /**
     * Returns the current symbol.
     * @private
     */
    private peek;
    /**
     * Returns the symbol after the current symbol.
     * @private
     */
    private peekNext;
    /**
     * Push a new token to the output list.
     *
     * @param type token type
     * @param literal token value
     * @param begin start index in source
     * @param end end index in source
     * @param position position in source (may be different from begin)
     * @private
     */
    private emitToken;
    /**
     * Prints an error message to the console, then throws an error.
     *
     * @param message error message
     * @param position position in source where the error occurred
     * @private
     */
    private errorOnPosition;
}