function arabicSentenceStartCheck(contextParams) {
    var char = contextParams.current;
    var prevChar = contextParams.get(-1);
    return (
        // ? an arabic char preceded with a non arabic char
        (isArabicChar(char) || isTashkeelArabicChar(char)) &&
        !isArabicChar(prevChar)
    );
}
Apply chaining context substitution format 3
@param {Array} substitutions substitutions
@param {any} tokens a list of tokens
@param {number} index token index