The basename root such that nameroot + nameext == basename, and
nameext is empty or begins with a period and contains at most one
period. For the purposes of path splitting leading periods on the
basename are ignored; a basename of .cshrc will have a nameroot of
.cshrc.
The implementation must set this field automatically based on the value
of basename prior to evaluating parameter references or expressions.
The basename root such that nameroot + nameext == basename, and nameext is empty or begins with a period and contains at most one period. For the purposes of path splitting leading periods on the basename are ignored; a basename of .cshrc will have a nameroot of .cshrc. The implementation must set this field automatically based on the value of basename prior to evaluating parameter references or expressions.