Character I/O

nl
nl/0 (B) A new line is started on the current output stream.

get0(N)
get0/1 (B) Nis the ASCII code of the next character from the current input stream. If the current input stream reaches its end of file, a -1 is returned (however, unlike in C-Prolog, the input stream is not closed on encountering end-of-file).

get(N)
get/1 (B) N is the ASCII code of the next non-blank printable character from the current input stream. It has the same behaviour as get0 on end of file.

put(N)
put/1 (B) ASCII character code N is output to the current output stream. N must be an integer.

tab(N)
tab/1 (B) N spaces are output to the current output stream. N must be an integer.