There is a very close relationship between HDSPAR, intended for bulk data parameters, and PAR,
intended for parameters which are simple, primitive-type values. If a parameter is given a primitive
value, The ADAM parameter system creates an HDS object in the program’s private parameter file
(usually ~/adam/program_name). The object has the name of the parameter and contains the given
value. This object is then associated with the parameter in the same way as DAT_ASSOC associates any
other object.
This relationship allows primitive values and HDS object names to be used interchangeably for parameter values to be accessed by either HDSPAR or PAR subroutines (subject, of course, to suitable type and dimensionality).
Try typing:
HDSTRACE (see SUN/102) would normally expect an HDS object (parameter OBJECT) as
input and uses DAT_ASSOC to open it. In this case it opens the parameter file component and
displays:
This feature also allows the program to handle parameters without knowing in advance the type of parameter which will be given.