Using sys.calls(), sys.frames() and match.call(), this utility function extracts and/or deducts information about the data being processed. Data frame name, variable names and labels if any, subsetting information, grouping information (when by() is used) are returned by the function which tries various methods to get this information.
parse_args(sys_calls, sys_frames, match_call, var = "x")Object created using sys.calls().
Object created using sys.frames().
Object created using match.call().
One of “x” or “y” (the latter being used only
in ctable).
A list comprised of:
df_name The data frame name when applicable.
var_names The variable names when applicable.
rows_subset The subsetting condition when applicable.
by_group The group, when functions are called through
by()
by_first A binary indicator used when function was called
through by()
by_last A binary indicator used when function was called
through by()