How to get error line and column on the script? if it throw error from custom function? #520

Hi chaiscript team.

i just want to know how to get exception error line on the script.

// imported function

std::shared_ptroc::ocImage imread(std::string _path, bool _isColor) {

cv::ImreadModes mode = cv::IMREAD_GRAYSCALE;

if (_isColor)
	mode = cv::IMREAD_COLOR;

cv::Mat cvImage = cv::imread(_path, mode);

if (cvImage.empty()) {
	OCERROR(error)
	OCERRORWRITE(error, "image file not found")
	throw std::runtime_error(error);
}

int depth = 1;
if (cvImage.depth() == CV_8U || cvImage.depth() == CV_8S)
	depth = 1;
else if (cvImage.depth() == CV_16U || cvImage.depth() == CV_16S)
	depth = 2;

std::shared_ptr<oc::ocImage> image = std::shared_ptr<oc::ocImage>(new oc::ocImage(cvImage.cols, cvImage.rows, cvImage.channels(), depth, cvImage.data));

return image;

}

/// Script txt
import("cv");

var image1 = cv.imread("D:\Github\OpenScript\TestScript\Lenna.png",false);
var test2 = cv.imread("D:\Github\OpenScript\TestScript\Lenna.png",true);

as you can see this function i made throw std::runtime_exception contain error information.
(this error info contain error line , ex: LINE , FUNCTION, with using custom macro function OCERROR)

but it not means that this throw contain error line on script like chaiscript::exception::eval_error's start_position.line, start_position.column

if i need to modify chaiscript source code ,,,, could you let me know how to do?

Thanks