Certain functions return integer values to identify datatypes of values. For example, these type codes are returned by the dataType() function in the "tads-gen" function set, and by the propDefined() method in the Object intrinsic class.
The type names shown below are macros that are defined in the system header file "systype.h".
TYPE_NIL – nil
TYPE_TRUE – true
TYPE_OBJECT – object
TYPE_PROP – property pointer
TYPE_INT – integer
TYPE_SSTRING – single-quoted string
TYPE_DSTRING – double-quoted string
TYPE_LIST – list
TYPE_CODE – executable code (i.e., the property is a method)
TYPE_FUNCPTR – function pointer
TYPE_NATIVE_CODE – native code (an intrinsic class method)
TYPE_ENUM - enumerator