handy marco for key-value binds support nil value in value list

KTOptionalBindings.txt

#define KTOptionalBindings(...) __KTOptionalBindings(@#__VA_ARGS__,__VA_ARGS__)
NSMutableDictionary *__KTOptionalBindings(NSString *command_value_list, id firstValue, ...) {
    va_list args;
    va_start(args, firstValue);
    NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];
    NSArray *keys = [command_value_list componentsSeparatedByString:@", "];
    NSInteger inputCount = keys.count;
    for (NSInteger i = 0; i < inputCount; i++) {
        NSString *key = keys[i];
        id val = nil;
        if (i == 0) {
            val = firstValue;
        } else {
            val = va_arg(args, id);
        }
        dict[key] = val;
    }
    va_end(args);
    return dict;
}