Group Expressions

One of the most useful routines within GRP is GRP_GROUP. This routine appends names to the end of a previously created group using a ``group expression'' obtained from the environment via a named parameter which can be of any type. The routine GRP_GRPEX also performs this function, except that the group expression is provided by the calling application, rather than being obtained through the parameter system.

This section describes the syntax of group expressions.