use queue

csv.diff

--- /home/shuji/gauche-dev/Gauche/lib/text/csv.scm	2013-06-01 15:43:19.339012570 +0900
+++ csv.scm	2013-06-03 16:05:43.100572304 +0900
@@ -31,16 +31,18 @@
 ;;;   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ;;;
 
-(define-module text.csv
+(define-module csv.csv
   (use srfi-1)
   (use srfi-11)
   (use srfi-13)
   (use gauche.regexp)
+  ;
+  (use util.queue)
   (export <csv>
           make-csv-reader
           make-csv-writer)
   )
-(select-module text.csv)
+(select-module csv.csv)
 
 ;; Parameters:
 ;;   separator - a character to be used to separate fields.
@@ -73,43 +75,48 @@
 
 (define (csv-reader sep quo)
   (define (eor? ch) (or (eqv? ch #\newline) (eof-object? ch)))
-
-  (define (start fields)
+  (define fields (make-queue))
+  (define (field-enqueue! x)   (enqueue! fields x) )
+  (define (field-dequeue-all!) (dequeue-all! fields))
+  ;
+  (define (start)
     (let1 ch (read-char)
-      (cond [(eor? ch) (reverse (cons "" fields))]
-            [(eqv? ch sep) (start (cons "" fields))]
-            [(eqv? ch quo) (quoted fields)]
-            [(char-whitespace? ch) (start fields)]
-            [else (unquoted (list ch) fields)])))
+      (cond [(eor? ch) (field-enqueue! "") (field-dequeue-all!) ]
+            ;
+            [(eqv? ch sep) (field-enqueue! "") (start) ]
+            ;
+            [(eqv? ch quo) (quoted) ]
+            [(char-whitespace? ch) (start)]
+            [else (unquoted (list ch) )])))
 
-  (define (unquoted chs fields)
+  (define (unquoted chs)
     (let loop ([ch (read-char)] [last chs] [chs chs])
-      (cond [(eor? ch) (reverse (cons (finish last) fields))]
-            [(eqv? ch sep) (start (cons (finish last) fields))]
+      (cond [(eor? ch)     (field-enqueue! (finish last)) (field-dequeue-all!) ]
+            [(eqv? ch sep) (field-enqueue! (finish last)) (start)]
             [(char-whitespace? ch) (loop (read-char) last (cons ch chs))]
             [else (let1 chs (cons ch chs)
                     (loop (read-char) chs chs))])))
 
-  (define (finish rchrs) (list->string (reverse rchrs)))
+  (define (finish rchrs) (list->string (reverse! rchrs)))
 
-  (define (quoted fields)
+  (define (quoted)
     (let loop ([ch (read-char)] [chs '()])
       (cond [(eof-object? ch) (error "unterminated quoted field")]
             [(eqv? ch quo)
              (if (eqv? (peek-char) quo)
                (begin (read-char) (loop (read-char) (cons quo chs)))
-               (quoted-tail (cons (finish chs) fields)))]
+               (begin (field-enqueue! (finish chs)) (quoted-tail) ) )]
             [else (loop (read-char) (cons ch chs))])))
 
-  (define (quoted-tail fields)
+  (define (quoted-tail)
     (let loop ([ch (read-char)])
-      (cond [(eor? ch) (reverse fields)]
-            [(eq? ch sep) (start fields)]
+      (cond [(eor? ch) (field-dequeue-all!)]
+            [(eq? ch sep) (start)]
             [else (loop (read-char))])))
 
   (if (eof-object? (peek-char))
     (eof-object)
-    (start '())))
+    (begin (field-dequeue-all!) (start) ) ))
 
 (define (make-csv-writer separator :optional (newline "\n") (quote-char #\"))
   (let* ((quote-string (string quote-char))