;;; Read characters from PORT until EOF, collect into a string.

(define (port->string port)
  (let ((sc (make-string-collector)))
    (letrec ((lp (lambda ()
		   (cond ((read-string 1024 port) =>
			  (lambda (s)
			    (collect-string! sc s)
			    (lp)))
			 (else (string-collector->string sc))))))
      (lp))))

;;; (loop (initial (sc (make-string-collector)))
;;;       (bind (s (read-string 1024 port)))
;;;       (while s)
;;;       (do (collect-string! sc s))
;;;       (result (string-collector->string sc)))

;;; Read items from PORT with READER until EOF. Collect items into a list.

(define (port->list reader port)
  (let lp ((ans '()))
    (let ((x (reader port)))
      (if (eof-object? x) (reverse! ans)
	  (lp (cons x ans))))))

(define (port->sexp-list port)
  (port->list read port))

(define (port->string-list port)
  (port->list read-line port))

(define (port-fold port reader op . seeds)
  (letrec ((fold (lambda seeds
		     (let ((x (reader port)))
		       (if (eof-object? x) (apply values seeds)
			   (call-with-values (lambda () (apply op x seeds))
					     fold))))))
    (apply fold seeds)))

(define reduce-port
  (deprecated-proc port-fold 'reduce-port "Use port-fold instead."))

;;; Not defined:
;;; (field-reader field-delims record-delims)
;;; Returns a reader that reads strings delimited by 1 or more chars from
;;; the string FIELD-DELIMS. These strings are collected in a list until
;;; eof or until 1 or more chars from RECORD-DELIMS are read. Then the
;;; accumulated list of strings is returned. For example, if we want
;;; a procedure that reads one line of input, splitting it into 
;;; whitespace-delimited strings, we can use 
;;;     (field-reader " \t" "\n")
;;; for a reader.



;; Loop until EOF reading characters or strings and writing (FILTER char)
;; or (FILTER string). Useful as an arg to FORK or FORK/PIPE.

(define (make-char-port-filter filter)
  (lambda ()
    (let lp ()
      (let ((c (read-char)))
	(if (not (eof-object? c))
	    (begin (write-char (filter c))
		   (lp)))))))

(define (make-string-port-filter filter . maybe-buflen)
  (let* ((buflen (:optional maybe-buflen 1024))
	 (buf (make-string buflen)))
    (lambda ()
      (let lp ()
	(cond ((read-string! buf 0 buflen) =>
	       (lambda (nread)
		 (display (filter (if (= nread buflen) buf
				      (substring buf 0 nread)))) ; last one.
		 (lp))))))))