batch io expanded

svn: r18766

collects/2htdp/batch-io.ss

@@ -3,19 +3,44 @@
 (require htdp/error)
 
 (define (read-file f)
-  (check-arg 'read-file (string? f) "string" "first" f)
+  (check-file f 'read-file)
   (check-arg 'read-file (file-exists? f) "name of file in program's folder" "first" f)
   (list->string
-    (with-input-from-file f 
-      (lambda ()
-	(let loop ([accu '()])
-	  (define nxt (read-char))
-	  (if (eof-object? nxt)
-	      (reverse (if (char=? (car accu) #\newline) (cdr accu) accu))
-	      (loop (cons nxt accu))))))))
- 
+   (with-input-from-file f 
+     (lambda ()
+       (let loop ([accu '()])
+         (define nxt (read-char))
+         (if (eof-object? nxt)
+             (reverse (if (char=? (car accu) #\newline) (cdr accu) accu))
+             (loop (cons nxt accu))))))))
+
+(define (read-file-as-lines f)
+  (check-file f 'read-file-as-lines)
+  (with-input-from-file f 
+    (lambda ()
+      (let loop ([accu '()])
+        (define nxt (read-line))
+        (if (eof-object? nxt)
+            (reverse accu)
+            (loop (cons nxt accu)))))))
+
+(define (read-file-as-1strings f)
+  (check-file f 'read-file-as-1strings)
+  (read-chars f string))
+
+;; 
+(define (read-chars f action)
+  (with-input-from-file f 
+    (lambda ()
+      (let loop ([accu '()])
+        (define nxt (read-char))
+        (if (eof-object? nxt)
+            (reverse (if (char=? (car accu) #\newline) (cdr accu) accu))
+            (loop (cons nxt accu)))))))
+
 (define (write-file f str)
-  (check-arg 'read-file (string? f) "string" "first" f)
+  (check-arg 'write-file (string? f) "name of file (string)" "first" f)
+  (check-arg 'write-file (string? str) "string" "second" str)
   (let ([result (not (file-exists? f))])
     (with-output-to-file f 
       (lambda () (printf "~a" str))
@@ -25,6 +50,9 @@
 ;; -----------------------------------------------------------------------------
 
 (provide 
+ read-file-as-lines ;; String -> [Listof String]
+ ;; read the fule f (in current-directory) as a list of strings
+ 
  read-file ;; String -> String
  ;; read the file f (in current-directory) as a string
  
@@ -34,6 +62,11 @@
  ;; true, if f doesn't exist
  )
 
+;; String[file name] Symbol -> Void
+;; effect: ensure that f is a file in current directory or report error for t
+(define (check-file f t)
+  (check-arg t (string? f) "string" "first" f)
+  (check-arg t (file-exists? f) "name of file in program's folder" "first" f))
 
 ;                                                                               
 ;                                                                               

collects/2htdp/tests/batch-io.ss

@@ -0,0 +1,43 @@
+#lang scheme 
+
+(require schemeunit)
+(require 2htdp/batch-io)
+
+(define file "batch-io.txt")
+
+(define test1 #<<eos
+test1
+eos
+)
+
+(define test2-as-list '("test1" "test2"))
+
+(define test2
+  (apply string-append 
+         (list (first test2-as-list)
+               (string #\newline)
+               (second test2-as-list))))
+
+(or (write-file file test1)
+    (check-true (string=? (read-file file) test1) "read-file 1"))
+
+(or (write-file file test2)
+    (check-true (string=? (read-file file) test2) "read-file 2"))
+
+(or (write-file file test1)
+    (check-equal? (read-file-as-lines file) (list test1) "read-file-as-lines 1"))
+
+(or (write-file file test2)
+    (check-equal? (read-file-as-lines file) test2-as-list "read-file-as-lines 2"))
+
+
+(check-exn exn:fail:contract? (lambda () (write-file 0 1)))
+(check-exn exn:fail:contract? (lambda () (write-file '("test") 1)))
+(check-exn exn:fail:contract? (lambda () (write-file "test" '("test"))))
+
+(check-exn exn:fail:contract? (lambda () (read-file 0)))
+(check-exn exn:fail:contract? (lambda () (read-file '("test"))))
+
+(check-exn exn:fail:contract? (lambda () (read-file-as-lines 0)))
+(check-exn exn:fail:contract? (lambda () (read-file-as-lines '("test"))))
+