IsUnknown only takes reals

[asalafranca]

IsUnknown only takes reals. It should work whith any grammar that has an
unkown constant defined like Matrix, Serie...

[danirus]

After an open discussion (in spanish) about this bug, accesible in:
​http://www.tol-project.org/pipermail/desarrollo-tol/2005-November/000193.html

There's a new function of Type "Anything", called "IsUnknownObject",
implementing the behavior you request. This function accepts any Variable or
Value and returns a Real "1" whether the given parameter has an Unknown value,
or "0" in other case.

Tol has unknown variables for the following Data Types:

Real:
Variable's Name: "?", value: "?"
Real IsUnknownObject(Real ?) returns 1

Date:
Variable's Name: "UnknownDate", value: "Unknown"
Real IsUnknownObject(UnknownDate) returns 1

Code:
Variable's Name: "UnknownCode", value: no value (an internal null pointer)
Real IsUnknownObject(UnknownCode) returns 1

Complex:
Variable's Name: "?", value: "(?)+i*(?)"
Real IsUnknownObject(Complex ?) returns 1

Matrix:
Variable's Name: "UnknownMatrix",
value: dumped as "?;" but it is a 1x1 matrix with an unknown value painted as a 0.0
A Matrix is unknown when one or more of their values is an unknown Real.
Real IsUnknownObject(Matrix ((0,1),(2,3))) returns 0
Real IsUnknownObject(Matrix ((0,1),(2,?))) returns 1

Polyn:
Variable's Name: "UnknownPolyn", value: "-?"
Real IsUnknownObject(UnknownPolyn) returns 1

Ratio:
Variable's Name: "UnknownRatio", value: "(-?) / (1.000000)"
Real IsUnknownObject(UnknownRatio) returns 1

Serie:
Variable's Name: "UnknownSerie", value unknown, dumped as "UnknownSerie"
Real IsUnknownObject(UnknownSerie) returns 1

There is no unknown value for Text, Set and TimeSet Data Types.