Function needed to create a frmt_structure object, which is a building block
of body_plan(). This specifies the rows the format will be applied to.
Arguments
- group_val
A string or a named list of strings which represent the value of group should be when the given frmt is implemented
- label_val
A string which represent the value of label should be when the given frmt is implemented
- ...
either a
frmt(),frmt_combine(), or afrmt_when()object. This can be named to also specify the parameter value
See also
body_plan() combines the frmt_structures to be applied to the
table body, and frmt(), frmt_combine(), and frmt_when() define the
format semantics.
