 | A pattern for integer or decimal notation:
-?((\d+\.\d*|\d*\.\d+)|\d+) |
| Can get rid of an OR by allowing the dot and digits behind
the dot be optional:
-?(\d+(\.\d*)?|\d*\.\d+) |
| Such a number, followed by an optional exponent (a la e+02),
makes up a general real number (!)
-?(\d+(\.\d*)?|\d*\.\d+)([eE][+\-]?\d+)? |
