[Guile-commits] 01/01: Support ~N in SRFI-19 string->date

[Daniel Llorens]

lloda pushed a commit to branch stable-2.2
in repository guile.

commit f74cfce4f1572931ec66616a32633c74874769fc
Author: Daniel Llorens <address@hidden>
Date:   Mon Dec 10 11:57:05 2018 +0100

    Support ~N in SRFI-19 string->date
    
    * module/srfi/srfi-19.scm (fractional-integer-reader,
      make-fractional-integer-reader): From reference implementation.
      (reader-directives): Handle #\N, from reference implementation.
    * test-suite/tests/srfi-19: Add tests for string->date ~N.
    * doc/ref/srfi-modules.texi (string->date): Add line for ~N.
---
 doc/ref/srfi-modules.texi     |  5 +++++
 module/srfi/srfi-19.scm       | 22 ++++++++++++++++++++++
 test-suite/tests/srfi-19.test | 10 ++++++++++
 3 files changed, 37 insertions(+)

diff --git a/doc/ref/srfi-modules.texi b/doc/ref/srfi-modules.texi
index 99967e5..11fa24d 100644
--- a/doc/ref/srfi-modules.texi
+++ b/doc/ref/srfi-modules.texi
@@ -2926,6 +2926,11 @@ the date.
 @tab minute
 @tab @nicode{date-minute}
 
address@hidden @nicode{~N}
address@hidden @nicode{char-numeric?}
address@hidden nanosecond
address@hidden @nicode{date-nanosecond}
+
 @item @nicode{~S}
 @tab @nicode{char-numeric?}
 @tab second
diff --git a/module/srfi/srfi-19.scm b/module/srfi/srfi-19.scm
index 46de91a..66939f9 100644
--- a/module/srfi/srfi-19.scm
+++ b/module/srfi/srfi-19.scm
@@ -1193,6 +1193,24 @@
   (lambda (port)
     (integer-reader upto port)))
 
+;; read an fractional integer upto n characters long on port; upto -> #f if 
any length
+;;
+;; The return value is normalized to upto decimal places. For example, if upto 
is 9 and
+;; the string read is "123", the return value is 123000000.
+(define (fractional-integer-reader upto port)
+  (define (accum-int port accum nchars)
+    (let ((ch (peek-char port)))
+      (if (or (eof-object? ch)
+              (not (char-numeric? ch))
+              (and upto (>= nchars  upto)))
+          (* accum (expt 10 (- upto nchars)))
+          (accum-int port (+ (* accum 10) (char->int (read-char port))) (+ 
nchars 1)))))
+  (accum-int port 0 0))
+
+(define (make-fractional-integer-reader upto)
+  (lambda (port)
+    (fractional-integer-reader upto port)))
+
 ;; read *exactly* n characters and convert to integer; could be padded
 (define (integer-reader-exact n port)
   (let ((padding-ok #t))
@@ -1305,6 +1323,7 @@
 (define read-directives
   (let ((ireader4 (make-integer-reader 4))
         (ireader2 (make-integer-reader 2))
+        (fireader9 (make-fractional-integer-reader 9))
         (eireader2 (make-integer-exact-reader 2))
         (locale-reader-abbr-weekday (make-locale-reader
                                      locale-abbr-weekday->index))
@@ -1343,6 +1362,9 @@
      (list #\M char-numeric? ireader2 (lambda (val object)
                                         (set-date-minute!
                                          object val)))
+     (list #\N char-numeric? fireader9 (lambda (val object)
+                                        (set-date-nanosecond!
+                                          object val)))
      (list #\S char-numeric? ireader2 (lambda (val object)
                                         (set-date-second! object val)))
      (list #\y char-fail eireader2
diff --git a/test-suite/tests/srfi-19.test b/test-suite/tests/srfi-19.test
index 4d79f10..256ff74 100644
--- a/test-suite/tests/srfi-19.test
+++ b/test-suite/tests/srfi-19.test
@@ -176,6 +176,16 @@ incomplete numerical tower implementation.)"
       (equal? "Sun Jun 05 18:33:00+0200 2005"
               (date->string date))))
 
+  (pass-if "string->date understands nanoseconds (1)"
+    (time=? (date->time-utc (string->date "2018-12-10 10:53:24.189"
+                                          "~Y-~m-~d ~H:~M:~S.~N"))
+            (date->time-utc (make-date 189000000 24 53 10 10 12 2018 3600))))
+
+  (pass-if "string->date understands nanoseconds (2)"
+    (time=? (date->time-utc (string->date "2018-12-10 10:53:24.189654321"
+                                          "~Y-~m-~d ~H:~M:~S.~N"))
+            (date->time-utc (make-date 189654321 24 53 10 10 12 2018 3600))))
+
   (pass-if "date->string pads small nanoseconds values correctly"
     (let* ((date (make-date 99999999 5 34 12 26 3 2017 0)))
       (equal? "099999999"