Checks the current call for an argument corresponding to
name.
The name can be one of the formal arguments or a named component
of
....
The behavior on
... distinguishes this function
from
!missing(name).
USAGE:
hasArg(names)
REQUIRED ARGUMENTS:
name
Name of one of the arguments to the function in which the call
to
hasArg occurs.
VALUE:
a logical value.
If
x is a standard argument,
hasArg(x) returns
TRUE
if
missing(x) is
FALSE.
Otherwise,
hasArg(x) returns
TRUE
if
... is an argument
and the actual call has a named argument of the form
"x=".