double SolveSpaceUI::ExprToMm(Expr *e) {
    return (e->Eval()) * MmPerUnit();
}
double SolveSpaceUI::StringToMm(const std::string &str) {
    return std::stod(str) * MmPerUnit();
}
double SolveSpace::StringToMm(const char *str) {
    return atof(str) * MmPerUnit();
}