prog.lisp

(let ((quicklisp-init (merge-pathnames "quicklisp/setup.lisp" (user-homedir-pathname))))
  (when (probe-file quicklisp-init)
    (load quicklisp-init)))

(with-open-file (*standard-output* "/dev/null" :direction :output
				   :if-exists :supersede)
		(ql:quickload :trivial-gray-streams))

(defvar *heads* (list))
(defvar *tails* (list))
(defvar *chunk-size* (* 4096 16))
(shadowing-import (list 'trivial-gray-streams:fundamental-character-output-stream
			'trivial-gray-streams:stream-write-char))

(defclass my-output-stream (fundamental-character-output-stream)
  ((count :initform 0)
   (buffer :initform (make-string *chunk-size*))))

(defmethod stream-write-char ((stream my-output-stream) character)
  (with-slots (count buffer) stream
    (setf (char buffer count) character)
    (incf count)
    (when (= count *chunk-size*)
      (format t "~a" buffer)
      (setf count 0))))

(defvar *my-out* (make-instance 'my-output-stream))

(setq *tails* (loop for line = (read-line *standard-input* nil :eof)
		    until (eq line :eof)
		    for sp = (position #\Space line)
		    for head = (subseq line 0 sp)
		    for tail = (string-trim '(#\Space #\return) (subseq line sp))
		    do (push head *heads*)
		    collect tail))
(setq *heads* (nreverse *heads*))

(loop for head in *heads*
      do (loop for tail in *tails*
	       do (format *my-out* "~a~a~%" head tail)))

(with-slots (count buffer) *my-out*
  (format t "~a" (subseq buffer 0 count)))