Some parameters are describing in the reference documentation as being associated with a group of objects. For instance, some parameters may require a group of strings, others may require a group of numerical values, or data files. No matter what the nature of the object, groups are specified using a syntax called a group expression. The GRP library is used to interpret these group expressions, and the GRP documentation , should be consulted for full details. A summary is given here.
A group expression can identify the members of the group in any of the following ways:
A typical group expression will often include characters that are of significance to the shell. If the group expression is supplied on the command line it may be necessary to place quotes around the string to prevent the shell from removing these characters. Two lots of quotes are usually required, as in the following example where a group expression (in this case, a comma-separated list) is used to specify a plotting style:
% display style='"grid=1,colour(grid)=red,title=My new image"'
These quotes are not required if the group expression is given in response to a prompt.
If the supplied group expression is terminated with a hyphen, the user is re-prompted for another group expression (using the same parameter). The objects specified by this second group expression are added to those specified by the first. This re-prompting continues until a group expression is supplied that does not end with a hyphen.
Certain classes of objects have additional features, for instance if the objects are the names of data files, then wild-card characters are allowed in the supplied values.
KAPPA --- Kernel Application Package