function ContextParams(context, currentIndex) {
    this.context = context;
    this.index = currentIndex;
    this.length = context.length;
    this.current = context[currentIndex];
    this.backtrack = context.slice(0, currentIndex);
    this.lookahead = context.slice(currentIndex + 1);
}
Converts a string into a list of tokens
@param {any} events tokenizer core events