The function (EXT:ELASTIC-NEWLINE [stream]) is like FRESH-LINE but the other way around: It outputs a conditional newline on stream, which is canceled if the next output on stream happens to be a newline. More precisely, it causes a newline to be output right before the next character is written on stream, if this character is not a newline. The newline is also output if the next operation on the stream is FRESH-LINE, FINISH-OUTPUT, FORCE-OUTPUT or CLOSE.

The functionality of EXT:ELASTIC-NEWLINE is also available through the FORMAT directive ~..

A technique for avoiding unnecessary blank lines in output is to begin each chunk of output with a call to FRESH-LINE and to terminate it with a call to EXT:ELASTIC-NEWLINE.

See also Section 21.6, “Newline Convention”.