It might be better to change the order of calls in
macintosh()
macintosh(5,3,12)
should be equivalent to
macintosh(width=5,height=2,pointsize=12)
at the time it complains about missing string constant
Error in Macintosh(display, width, height, pointsize) :
invalid string argument
I guess instead of
macintosh
function (display = "", width = 5, height = 5, pointsize = 12)
.Internal(Macintosh(display, width, height, pointsize))
use better
macintosh
function (width = 5, height = 5, pointsize = 12, display = "")
.Internal(Macintosh(display, width, height, pointsize))
(or/and change the documentation to include display.)