(EXT:MAKE-BUFFERED-OUTPUT-STREAM function). Returns a buffered output STREAM. function is a FUNCTION expecting one argument, a SIMPLE-STRING. WRITE-CHAR collects the CHARACTERs in a STRING, until a newline character is written or FORCE-OUTPUT/FINISH-OUTPUT is called. Then function is called with a SIMPLE-STRING as argument, that contains the characters collected so far. CLEAR-OUTPUT discards the characters collected so far.

(EXT:MAKE-BUFFERED-INPUT-STREAM function mode). Returns a buffered input STREAM. function is a FUNCTION of 0 arguments that returns either NIL (stands for end-of-stream) or up to three values string, start, end. READ-CHAR returns the CHARACTERs of the current string one after another, as delimited by start and end, which default to 0 and NIL, respectively. When the string is consumed, function is called again. The string returned by function should not be changed by the user. function should copy the string with COPY-SEQ or SUBSEQ before returning if the original string is to be modified. mode determines the behavior of LISTEN when the current string buffer is empty:

CLEAR-INPUT discards the rest of the current string, so function will be called upon the next READ-CHAR operation.