<< obj (type?) data_conversion type >>
<< obj (type??) data_conversion type >>
<< obj (key word) data_conversion obj >>
integer type; object obj;
Key words: null, integer, literal, dollar, string, poly, universalNumber,
           ring, numerator, denominator, double, cancel,
           map, orderMatrix, error, 
 or [(class) (class-name)].
The primitive reports and converts the data type of obj.
Special combinations of obj and keyword.
   ring (oxRingStructure) data_conversion list
Example: (2) (integer) data_conversion ===> 2

Nobuki Takayama 2020-11-24