isDirectory fn
i1 : isDirectory "." o1 = true
i2 : fn = temporaryFileName() o2 = /tmp/M2-499355-0/0
i3 : fn << "hi there" << close o3 = /tmp/M2-499355-0/0 o3 : File
i4 : isDirectory fn o4 = false
i5 : removeFile fn
The object isDirectory is a compiled function.