Describe variable types.

You can find more information in comments below.

enum VARIABLE_TYPE
    {
        vtString,      // Variable is string 
        vtIdentifier,  // Variable is identifier 
        vtInteger,     // Variable is integer 
        vtFloat,       // Variable is float 
        vtRange,       // Variable is range(have 2 items: from..to) 
        vtArray        // Variable is array of other values 
    };