QScriptEngine with negative numbers, pe: 5*-2

Question

I'm trying to run a script which evaluates only expressions that have add, subs, mults and divs, but can use negative numbers. This negative numbers are taken from instructions like this:

set 1, 5 * D[5]

This implies that you have to store the result of 5 * [whatever it's in a variable]. If this variable contains a negative number, let's say -2, the expression will be 5*-2, and this expression is evaluated by QScriptEngine, resulting 0 (Error). I need to parse expressions like this to be 5*(-2). In PERL, a RegExp to do it will be:

$expresion =~ s/\[\\*\\+\\-\\/](\\-\d+)/($1)/g;

How can I do this in Qt?

Answer 1

QString s = "...";
s.replace(QRegExp("[\\*\\+\\-\\/](\\-\\d+)"), "\\1");

See http://doc.qt.io/qt-4.8/qstring.html#replace-16