78 lines
2.3 KiB
Scheme
78 lines
2.3 KiB
Scheme
;;; 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))))))))
|