I feel like the responsible thing to do here is throw an error if you encounter an unexpected character. Others have already pointed out that there's an actual

I feel like the responsible thing to do here is throw an error if you encounter an unexpected character. Others have already pointed out that there's an actual minus sign character that would break this. This code is dealing with like four different tricky/unpredictable things (parsing PDFs, parsing strings, unicode, money) and the lack of basic exception handling should raise alarm bells.