Reads the next element from the stream but does not advance the stream’s position. Handles end-of-stream conditions just as read-element does.
open
| stream | An instance of <stream>. |
| on-end-of-stream: | An instance of <object>. The default is $not-supplied. |
| element-or-eof | An instance of <object> or the value on-end-of-stream:. |