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(define-module (ice-9 rdelim) |
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#:export (read-line |
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read-line! |
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read-delimited |
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read-delimited! |
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read-string |
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read-string! |
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%read-delimited! |
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%read-line |
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write-line)) |
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(%init-rdelim-builtins) |
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(define* (read-line! string #:optional (port current-input-port)) |
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(define scm-line-incrementors "\n") |
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(let* ((rv (%read-delimited! scm-line-incrementors |
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string |
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#t |
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port)) |
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(terminator (car rv)) |
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(nchars (cdr rv))) |
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(cond ((and (= nchars 0) |
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(eof-object? terminator)) |
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terminator) |
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((not terminator) #f) |
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(else nchars)))) |
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(define* (read-delimited! delims buf #:optional |
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(port (current-input-port)) (handle-delim 'trim) |
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(start 0) (end (string-length buf))) |
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(let* ((rv (%read-delimited! delims |
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buf |
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(not (eq? handle-delim 'peek)) |
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port |
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start |
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end)) |
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(terminator (car rv)) |
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(nchars (cdr rv))) |
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(cond ((or (not terminator) |
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(eof-object? terminator)) |
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(if (zero? nchars) |
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(if (eq? handle-delim 'split) |
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(cons terminator terminator) |
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terminator) |
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(if (eq? handle-delim 'split) |
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(cons nchars terminator) |
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nchars))) |
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(else |
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(case handle-delim |
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((trim peek) nchars) |
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((concat) (string-set! buf (+ nchars start) terminator) |
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(+ nchars 1)) |
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((split) (cons nchars terminator)) |
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(else (error "unexpected handle-delim value: " |
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handle-delim))))))) |
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(define* (read-delimited delims #:optional (port (current-input-port)) |
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(handle-delim 'trim)) |
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(let loop ((substrings '()) |
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(total-chars 0) |
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(buf-size 100)) |
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(let* ((buf (make-string buf-size)) |
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(rv (%read-delimited! delims |
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buf |
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(not (eq? handle-delim 'peek)) |
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port)) |
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(terminator (car rv)) |
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(nchars (cdr rv)) |
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(new-total (+ total-chars nchars))) |
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(cond |
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((not terminator) |
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(loop (cons (substring buf 0 nchars) substrings) |
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new-total |
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(* buf-size 2))) |
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((and (eof-object? terminator) (zero? new-total)) |
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(if (eq? handle-delim 'split) |
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(cons terminator terminator) |
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terminator)) |
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(else |
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(let ((joined |
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(string-concatenate-reverse |
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(cons (substring buf 0 nchars) substrings)))) |
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(case handle-delim |
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((concat) |
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(if (eof-object? terminator) |
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joined |
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(string-append joined (string terminator)))) |
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((trim peek) joined) |
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((split) (cons joined terminator)) |
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(else (error "unexpected handle-delim value: " |
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handle-delim))))))))) |
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(define-syntax-rule (check-arg exp message arg ...) |
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(unless exp |
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(error message arg ...))) |
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(define (index? n) |
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(and (integer? n) (exact? n) (>= n 0))) |
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(define* (read-string! buf #:optional |
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(port (current-input-port)) |
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(start 0) (end (string-length buf))) |
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"Read all of the characters out of PORT and write them to BUF. |
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Returns the number of characters read. |
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This function only reads out characters from PORT if it will be able to |
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write them to BUF. That is to say, if BUF is smaller than the number of |
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available characters, then BUF will be filled, and characters will be |
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left in the port." |
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(check-arg (string? buf) "not a string" buf) |
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(check-arg (index? start) "bad index" start) |
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(check-arg (index? end) "bad index" end) |
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(check-arg (<= start end) "start beyond end" start end) |
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(check-arg (<= end (string-length buf)) "end beyond string length" end) |
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(let lp ((n start)) |
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(if (< n end) |
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(let ((c (read-char port))) |
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(if (eof-object? c) |
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(- n start) |
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(begin |
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(string-set! buf n c) |
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(lp (1+ n))))) |
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(- n start)))) |
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(define* read-string |
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(case-lambda* |
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"Read all of the characters out of PORT and return them as a string. |
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If the COUNT argument is present, treat it as a limit to the number of |
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characters to read. By default, there is no limit." |
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((#:optional (port (current-input-port))) |
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|
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(let loop ((head (make-string 30)) (pos 0) (tail '())) |
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(let ((char (read-char port))) |
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(cond |
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((eof-object? char) |
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(let ((head (substring head 0 pos))) |
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(if (null? tail) |
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(substring head 0 pos) |
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(string-concatenate-reverse tail head pos)))) |
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(else |
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(string-set! head pos char) |
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(if (< (1+ pos) (string-length head)) |
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(loop head (1+ pos) tail) |
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(loop (make-string (* (string-length head) 2)) 0 |
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(cons head tail)))))))) |
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((port count) |
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(let loop ((chars '()) |
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(total 0)) |
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(let ((char (read-char port))) |
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(if (or (eof-object? char) (>= total count)) |
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(list->string (reverse chars)) |
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(loop (cons char chars) (+ 1 total)))))))) |
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(define* (read-line #:optional (port (current-input-port)) |
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(handle-delim 'trim)) |
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(let* ((line/delim (%read-line port)) |
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(line (car line/delim)) |
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(delim (cdr line/delim))) |
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(case handle-delim |
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((trim) line) |
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((split) line/delim) |
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((concat) (if (and (string? line) (char? delim)) |
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(string-append line (string delim)) |
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line)) |
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((peek) (if (char? delim) |
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(unread-char delim port)) |
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line) |
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(else |
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(error "unexpected handle-delim value: " handle-delim))))) |
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