From bd9733926076885e3417b74de76e4c9c7bc56254 Mon Sep 17 00:00:00 2001
From: Bryan Newbold <bnewbold@robocracy.org>
Date: Mon, 20 Feb 2017 00:05:28 -0800
Subject: Import Upstream version 2c7

---
 lineio.scm | 68 +++++++++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 50 insertions(+), 18 deletions(-)

(limited to 'lineio.scm')

diff --git a/lineio.scm b/lineio.scm
index ad8320b..c80ece8 100644
--- a/lineio.scm
+++ b/lineio.scm
@@ -17,34 +17,66 @@
 ;promotional, or sales literature without prior written consent in
 ;each case.
 
-(define (read-line . arg)
-  (let* ((char (apply read-char arg)))
+
+;;@args
+;;@args port
+;;Returns a string of the characters up to, but not including a
+;;newline or end of file, updating @var{port} to point to the
+;;character following the newline.  If no characters are available, an
+;;end of file object is returned.  The @var{port} argument may be
+;;omitted, in which case it defaults to the value returned by
+;;@code{current-input-port}.
+(define (read-line . port)
+  (let* ((char (apply read-char port)))
     (if (eof-object? char)
 	char
-	(do ((char char (apply read-char arg))
+	(do ((char char (apply read-char port))
 	     (clist '() (cons char clist)))
 	    ((or (eof-object? char) (char=? #\newline char))
 	     (list->string (reverse clist)))))))
 
-(define (read-line! str . arg)
-  (let* ((char (apply read-char arg))
-	 (len (+ -1 (string-length str))))
+;;@args string
+;;@args string port
+;;Fills @1 with characters up to, but not including a newline or end
+;;of file, updating the @var{port} to point to the last character read
+;;or following the newline if it was read.  If no characters are
+;;available, an end of file object is returned.  If a newline or end
+;;of file was found, the number of characters read is returned.
+;;Otherwise, @code{#f} is returned.  The @var{port} argument may be
+;;omitted, in which case it defaults to the value returned by
+;;@code{current-input-port}.
+(define (read-line! str . port)
+  (let* ((char (apply read-char port))
+	 (midx (+ -1 (string-length str))))
     (if (eof-object? char)
 	char
-	(do ((char char (apply read-char arg))
+	(do ((char char (apply read-char port))
 	     (i 0 (+ 1 i)))
 	    ((or (eof-object? char)
 		 (char=? #\newline char)
-		 (>= i len))
-	     (cond ((or (eof-object? char) (char=? #\newline char))
-		    i)
-		   (else
-		    (string-set! str i char)
-		    (set! char (apply peek-char arg))
-		    (if (or (eof-object? char) (char=? #\newline char))
-			(+ 1 i) #f))))
+		 (> i midx))
+	     (if (> i midx) #f i))
 	  (string-set! str i char)))))
 
-(define (write-line str . arg)
-  (apply display str arg)
-  (apply newline arg))
+;;@args string
+;;@args string port
+;;Writes @1 followed by a newline to the given @var{port} and returns
+;;an unspecified value.  The @var{Port} argument may be omited, in
+;;which case it defaults to the value returned by
+;;@code{current-input-port}.@refill
+(define (write-line str . port)
+  (apply display str port)
+  (apply newline port))
+
+;;@args path
+;;@args path port
+;;Displays the contents of the file named by @1 to @var{port}.  The
+;;@var{port} argument may be ommited, in which case it defaults to the
+;;value returned by @code{current-output-port}.
+(define (display-file path . port)
+  (set! port (if (null? port) (current-output-port) (car port)))
+  (call-with-input-file path
+    (lambda (inport)
+      (do ((line (read-line inport) (read-line inport)))
+	  ((eof-object? line))
+	(write-line line port)))))
-- 
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