From 10b73053d1cbef78fd325686e04f82f74d9d6e5c Mon Sep 17 00:00:00 2001
From: Jinser Kafka <aimer@purejs.icu>
Date: Fri, 30 Jan 2026 17:24:08 +0800
Subject: [PATCH 01/15] feat(srfi-19): init

---
 goldfish/scheme/time.scm          |  21 +-
 goldfish/srfi/srfi-19.scm         | 560 +++++++++++++++++++++++++++
 src/goldfish.hpp                  |  56 ++-
 tests/goldfish/liii/time-test.scm | 615 +++++++++++++++++++++++++++++-
 4 files changed, 1235 insertions(+), 17 deletions(-)
 create mode 100644 goldfish/srfi/srfi-19.scm

diff --git a/goldfish/scheme/time.scm b/goldfish/scheme/time.scm
index 3630dfb9..8993c02e 100644
--- a/goldfish/scheme/time.scm
+++ b/goldfish/scheme/time.scm
@@ -15,15 +15,26 @@
 ;
 
 (define-library (scheme time)
-  (export current-second current-jiffy jiffies-per-second)
+  (import (only (scheme base) let-values))
+  (export current-second current-jiffy jiffies-per-second
+          get-time-of-day monotonic-nanosecond
+          system-clock-resolution steady-clock-resolution)
   (begin
 
     (define (jiffies-per-second) 1000000)
 
-    (define (current-second) (g_current-second))
+    (define get-time-of-day g_get-time-of-day)
+    (define monotonic-nanosecond g_monotonic-nanosecond)
+    (define system-clock-resolution g_system-clock-resolution)
+    (define steady-clock-resolution g_steady-clock-resolution)
+
+    (define (current-second)
+      (let-values (((sec usec) (get-time-of-day)))
+        (+ sec (exact->inexact (/ usec 1000000)))))
 
     (define (current-jiffy)
-      (round (* (current-second) (jiffies-per-second))))
+      ;; NOTE: use the s7-round to ensure that a natural number is returned.
+      (s7-round (* (current-second) (jiffies-per-second))))))
 
-    ) ; end of begin
-  ) ; end of define-library
+     ; end of begin
+   ; end of define-library
diff --git a/goldfish/srfi/srfi-19.scm b/goldfish/srfi/srfi-19.scm
new file mode 100644
index 00000000..38bec21b
--- /dev/null
+++ b/goldfish/srfi/srfi-19.scm
@@ -0,0 +1,560 @@
+;
+; Copyright (C) 2026 The Goldfish Scheme Authors
+;
+; Licensed under the Apache License, Version 2.0 (the "License");
+; you may not use this file except in compliance with the License.
+; You may obtain a copy of the License at
+;
+; http://www.apache.org/licenses/LICENSE-2.0
+;
+; Unless required by applicable law or agreed to in writing, software
+; distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+; WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+; License for the specific language governing permissions and limitations
+; under the License.
+;
+
+;;
+;; SRFI-19 Implementation for Goldfish Scheme
+;;
+;; This is a heavily modified implementation of SRFI-19 "Time Data Types
+;; and Procedures". While based on the original reference implementation,
+;; nearly every function has been rewritten for performance, clarity, or
+;; to adapt to Goldfish Scheme's idioms.
+;;
+;; ======================================================================
+;; SRFI-19: Time Data Types and Procedures.
+;;
+;; Copyright (C) I/NET, Inc. (2000, 2002, 2003). All Rights Reserved.
+;;
+;; Permission is hereby granted, free of charge, to any person obtaining
+;; a copy of this software and associated documentation files (the
+;; "Software"), to deal in the Software without restriction, including
+;; without limitation the rights to use, copy, modify, merge, publish,
+;; distribute, sublicense, and/or sell copies of the Software, and to
+;; permit persons to whom the Software is furnished to do so, subject to
+;; the following conditions:
+;;
+;; The above copyright notice and this permission notice shall be
+;; included in all copies or substantial portions of the Software.
+;;
+;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+;; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+;; MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+;; NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+;; LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+;; OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+;; WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+(define-library (srfi srfi-19)
+  (import (rename (scheme time)
+                  (get-time-of-day      glue:get-time-of-day)
+                  (monotonic-nanosecond glue:monotonic-nanosecond))
+          (only (srfi srfi-13) string-pad string-tokenize string-trim-right))
+  (export
+    ;; Constants
+    TIME-DURATION TIME-MONOTONIC TIME-PROCESS
+    TIME-TAI      TIME-THREAD    TIME-UTC
+    ;; Time object and accessors
+    make-time time?
+    time-type      time-nanosecond      time-second
+    set-time-type! set-time-nanosecond! set-time-second!
+    copy-time
+    ;; Time comparison procedures
+    ;; Time arithmetic procedures
+    ;; Current time and clock resolution
+    current-date current-julian-day current-time time-resolution
+    ;; Date object and accessors
+    make-date date?
+    date-nanosecond date-second date-minute date-hour
+    date-day        date-month  date-year   date-zone-offset
+    ;; Time/Date/Julian Day/Modified Julian Day Converters
+    ;; Date to String/String to Date Converters
+    date->string)
+  (begin
+
+    ;; ====================
+    ;; Constants
+    ;; ====================
+
+    (define TIME-DURATION  'time-duration)
+    (define TIME-MONOTONIC 'time-monotonic)
+    (define TIME-PROCESS   'time-process)
+    (define TIME-TAI       'time-tai)
+    (define TIME-THREAD    'time-thread)
+    (define TIME-UTC       'time-utc)
+
+    (define priv:LOCALE-DECIMAL-POINT ".")
+
+    (define priv:LOCALE-ABBR-WEEKDAY-VECTOR (vector "Sun" "Mon" "Tue" "Wed"
+                                                    "Thu" "Fri" "Sat"))
+    (define priv:LOCALE-LONG-WEEKDAY-VECTOR (vector "Sunday" "Monday"
+                                                    "Tuesday" "Wednesday"
+                                                    "Thursday" "Friday"
+                                                    "Saturday"))
+    ;; note empty string in 0th place.
+    (define priv:LOCALE-ABBR-MONTH-VECTOR   (vector "" "Jan" "Feb" "Mar"
+                                                    "Apr" "May" "Jun" "Jul"
+                                                    "Aug" "Sep" "Oct" "Nov"
+                                                    "Dec"))
+    (define priv:LOCALE-LONG-MONTH-VECTOR   (vector "" "January" "February"
+                                                    "March" "April" "May"
+                                                    "June" "July" "August"
+                                                    "September" "October"
+                                                    "November" "December"))
+
+    (define priv:LOCALE-PM "PM")
+    (define priv:LOCALE-AM "AM")
+
+    ;; See `date->string` below
+    (define priv:LOCALE-DATE-TIME-FORMAT   "~a ~b ~d ~H:~M:~S~z ~Y")
+    (define priv:LOCALE-SHORT-DATE-FORMAT  "~m/~d/~y")
+    (define priv:LOCALE-TIME-FORMAT        "~H:~M:~S")
+    (define priv:ISO-8601-DATE-TIME-FORMAT "~Y-~m-~dT~H:~M:~S~z")
+
+    (define priv:NANO            (expt 10 9))
+    (define priv:SID             86400)     ; seconds in a day
+    (define priv:SIHD            43200)     ; seconds in a half day
+    (define priv:TAI-EPOCH-IN-JD 4881175/2) ; julian day number for 'the epoch'
+
+    ;; ====================
+    ;; Time object and accessors
+    ;; ====================
+
+    (define-record-type <time>
+      (%make-time type nanosecond second)
+      time?
+      (type       time-type       set-time-type!)
+      (nanosecond time-nanosecond set-time-nanosecond!)
+      (second     time-second     set-time-second!))
+
+    (define (make-time type nanosecond second)
+      (unless (and (integer? nanosecond)
+                   (integer? second))
+        (error 'wrong-type-arg "nanosecond and second should be integer"))
+      (unless (member type (map car priv:TIME-DISPATCH))
+        (value-error "unsupported time type" type))
+      (%make-time type nanosecond second))
+
+    (define (copy-time time)
+      (make-time (time-type       time)
+                 (time-nanosecond time)
+                 (time-second     time)))
+
+    ;; ====================
+    ;; Time comparison procedures
+    ;; ====================
+
+    ;; TODO
+
+    ;; ====================
+    ;; Time arithmetic procedures
+    ;; ====================
+
+    ;; TODO
+
+    ;; ====================
+    ;; Current time and clock resolution
+    ;; ====================
+
+    (define (priv:us->ns us) (* us 1000))
+
+    ;; NOTE:
+    ;; 此函数使用静态的闰秒偏移表 `priv:leap-second-table`
+    ;; 来计算 TAI（国际原子时）与 UTC 之间的差值。
+    ;; 该表包含了自1972年UTC系统引入闰秒机制以来，所有闰秒生效的时刻（Unix时间戳）
+    ;; 以及从该时刻起，TAI 领先 UTC 的总秒数。
+    ;;
+    ;; 表格结构：((生效时间戳1 . 总偏移量1) (生效时间戳2 . 总偏移量2) ...)
+    ;; 数据排列：最新的条目（时间戳最大）在前。
+    ;; 数据来源：基于巴黎天文台等机构维护的闰秒历史记录生成。
+    ;;
+    ;; 工作原理：对于给定的 UTC 时间戳 `s`，函数从新到旧遍历此表，
+    ;; 找到第一个 `生效时间戳 <= s` 的条目，并使用其对应的总偏移量。
+    ;; 如果 `s` 早于表格中的最早记录（1972年之前），则返回初始偏移量 10 秒。
+    ;;
+    ;; 当前限制：
+    ;; 1. 此表为静态数据。未来若有新的闰秒引入（如 IANA 文件所示，有效期至 2026-06-28），
+    ;;    需要手动更新此表，在列表最前面添加新条目。
+    ;; 2. 更动态的实现应考虑从外部权威源
+    ;;   （如 https://hpiers.obspm.fr/iers/bul/bulc/ntp/leap-seconds.list）
+    ;;    在程序启动时或定期加载并解析闰秒数据。
+    ;;
+    ;; 参考资料：
+    ;; - IANA 闰秒数据文件: https://data.iana.org/time-zones/tzdb/leapseconds
+    ;; - 巴黎天文台闰秒文件：https://hpiers.obspm.fr/iers/bul/bulc/ntp/leap-seconds.list
+    (define priv:leap-second-table
+      '((1483228800 . 37)   ; 2017-01-01 00:00:00 UTC 起，TAI-UTC = 37 秒
+        (1435708800 . 36)   ; 2015-07-01 00:00:00 UTC 起，TAI-UTC = 36 秒
+        (1341100800 . 35)   ; 2012-07-01 00:00:00 UTC 起，TAI-UTC = 35 秒
+        (1230768000 . 34)   ; 2009-01-01 00:00:00 UTC 起，TAI-UTC = 34 秒
+        (1136073600 . 33)   ; 2006-01-01 00:00:00 UTC 起，TAI-UTC = 33 秒
+        (915148800  . 32)   ; 1999-01-01 00:00:00 UTC 起，TAI-UTC = 32 秒
+        (867715200  . 31)   ; 1997-07-01 00:00:00 UTC 起，TAI-UTC = 31 秒
+        (820454400  . 30)   ; 1996-01-01 00:00:00 UTC 起，TAI-UTC = 30 秒
+        (773020800  . 29)   ; 1994-07-01 00:00:00 UTC 起，TAI-UTC = 29 秒
+        (741484800  . 28)   ; 1993-07-01 00:00:00 UTC 起，TAI-UTC = 28 秒
+        (709948800  . 27)   ; 1992-07-01 00:00:00 UTC 起，TAI-UTC = 27 秒
+        (662688000  . 26)   ; 1991-01-01 00:00:00 UTC 起，TAI-UTC = 26 秒
+        (631152000  . 25)   ; 1990-01-01 00:00:00 UTC 起，TAI-UTC = 25 秒
+        (567993600  . 24)   ; 1988-01-01 00:00:00 UTC 起，TAI-UTC = 24 秒
+        (489024000  . 23)   ; 1985-07-01 00:00:00 UTC 起，TAI-UTC = 23 秒
+        (425865600  . 22)   ; 1983-07-01 00:00:00 UTC 起，TAI-UTC = 22 秒
+        (394329600  . 21)   ; 1982-07-01 00:00:00 UTC 起，TAI-UTC = 21 秒
+        (362793600  . 20)   ; 1981-07-01 00:00:00 UTC 起，TAI-UTC = 20 秒
+        (315532800  . 19)   ; 1980-01-01 00:00:00 UTC 起，TAI-UTC = 19 秒
+        (283996800  . 18)   ; 1979-01-01 00:00:00 UTC 起，TAI-UTC = 18 秒
+        (252460800  . 17)   ; 1978-01-01 00:00:00 UTC 起，TAI-UTC = 17 秒
+        (220924800  . 16)   ; 1977-01-01 00:00:00 UTC 起，TAI-UTC = 16 秒
+        (189302400  . 15)   ; 1976-01-01 00:00:00 UTC 起，TAI-UTC = 15 秒
+        (157766400  . 14)   ; 1975-01-01 00:00:00 UTC 起，TAI-UTC = 14 秒
+        (126230400  . 13)   ; 1974-01-01 00:00:00 UTC 起，TAI-UTC = 13 秒
+        (94694400   . 12)   ; 1973-01-01 00:00:00 UTC 起，TAI-UTC = 12 秒
+        (78796800   . 11)   ; 1972-07-01 00:00:00 UTC 起，TAI-UTC = 11 秒
+        (63072000   . 10))) ; 1972-01-01 00:00:00 UTC 起，TAI-UTC = 10 秒
+                            ; 注：1972年之前，UTC与TAI的理论差也为10秒，但当时无正式闰秒机制。
+    (define (priv:leap-second-delta s)
+      (let lp ((table priv:leap-second-table))
+        (cond
+          ((null? table)       10) ; 理论值
+          ((>= s (caar table)) (cdar table))
+          (else                (loop (cdr table))))))
+
+    (define (priv:current-time-monotonic)
+      (receive (s ns) (floor/ (glue:monotonic-nanosecond) 1000000000) ; 1e9
+       (make-time TIME-MONOTONIC ns s)))
+
+    (define (priv:current-time-process)
+      (error "unimplemented time"))
+
+    (define (priv:current-time-tai)
+      (receive (s us) (glue:get-time-of-day)
+        (make-time TIME-TAI
+                   (priv:us->ns us)
+                   (+ s (priv:leap-second-delta s)))))
+
+    (define (priv:current-time-thread)
+      (error "unimplemented time"))
+
+    (define (priv:current-time-utc)
+      (receive (s us) (glue:get-time-of-day)
+        (make-time TIME-UTC (priv:us->ns us) s)))
+
+    (define priv:TIME-DISPATCH
+       `((,TIME-MONOTONIC . (,priv:current-time-monotonic . ,steady-clock-resolution))
+         ; (,TIME-PROCESS   . (,priv:current-time-process   . ,0))
+         (,TIME-TAI       . (,priv:current-time-tai       . ,system-clock-resolution))
+         ; (,TIME-THREAD    . (,priv:current-time-thread    . ,0))
+         (,TIME-UTC       . (,priv:current-time-utc       . ,system-clock-resolution))))
+    (define (priv:query-time-dispatch clock-type querier)
+      (let ((entry (assq clock-type priv:TIME-DISPATCH)))
+        (if entry
+          (querier entry)
+          (error 'wrong-type-arg "unsupported time type" clock-type))))
+
+    ;; ====================
+
+    (define* (current-date (tz-offset 'TODO-GET-LOCAL-TZ-FROM-OS))
+      (error 'todo "TODO"))
+
+    (define (current-julian-day)
+      (error 'todo "TODO"))
+
+    (define* (current-time (clock-type TIME-UTC))
+      ((priv:query-time-dispatch clock-type cadr)))
+
+    (define* (time-resolution (clock-type TIME-UTC))
+      (priv:query-time-dispatch clock-type cddr))
+
+    ;; ====================
+    ;; Date object and accessors
+    ;; ====================
+
+    ;; Date objects are immutable once created
+    (define-record-type <date>
+      (%make-date nanosecond second minute hour day month year zone-offset)
+      date?
+      (nanosecond  date-nanosecond)
+      (second      date-second)
+      (minute      date-minute)
+      (hour        date-hour)
+      (day         date-day)
+      (month       date-month)
+      (year        date-year)
+      (zone-offset date-zone-offset))
+
+    (define (make-date nanosecond second minute hour day month year zone-offset)
+      ;; TODO: more guards maybe
+      (unless (and (integer? nanosecond) (integer? second)
+                   (integer? minute)     (integer? hour)
+                   (integer? day)        (integer? month)
+                   (integer? year)       (integer? zone-offset))
+        (error 'wrong-type-arg "The date fields need to be integer"))
+      (%make-date nanosecond second minute hour day month year zone-offset))
+
+    ;; ====================
+
+    (define (priv:leap-year? year)
+      (cond
+        ((zero? (modulo year 400)) #t)
+        ((zero? (modulo year 100)) #f)
+        ((zero? (modulo year 4))   #t)
+        (else                      #f)))
+
+    (define priv:MONTH-ASSOC '((0 . 0)   (1 . 31)  (2 . 59)   (3 . 90)
+                               (4 . 120) (5 . 151) (6 . 181)  (7 . 212)
+                               (8 . 243) (9 . 273) (10 . 304) (11 . 334)))
+
+    (define (priv:year-day day month year)
+      (let ((days-pr (assoc (- month 1) priv:MONTH-ASSOC)))
+        (unless days-pr
+          (value-error "invalid month specified" month))
+        ;; 闰2月，所以2月之后，且当年是闰年的，要多一天
+        (if (and (priv:leap-year? year) (> month 2))
+          (+ day (cdr days-pr) 1)
+          (+ day (cdr days-pr)))))
+
+    ;; ====================
+
+    (define (priv:week-day day month year)
+      (let* ((yy (if (negative? year) (+ year 1) year))
+             (a (quotient (- 14 month) 12))
+             (y (- yy a))
+             (m (+ month (* 12 a) -2)))
+        (modulo (+ day
+                   y
+                   (floor-quotient y 4)
+                   (- (floor-quotient y 100))
+                   (floor-quotient y 400)
+                   (floor-quotient (* 31 m) 12))
+                7)))
+
+    (define (priv:days-before-first-week date day-of-week-starting-week)
+      (let* ((first-day (make-date 0 0 0 0
+                                   1
+                                   1
+                                   (date-year date)
+                                   0))
+             (fdweek-day (date-week-day first-day)))
+        (modulo (- day-of-week-starting-week fdweek-day)
+                7)))
+
+    (define (date-year-day date)
+      (priv:year-day (date-day   date)
+                     (date-month date)
+                     (date-year  date)))
+
+    (define (date-week-day date)
+      (priv:week-day (date-day   date)
+                     (date-month date)
+                     (date-year  date)))
+
+    (define (date-week-number date day-of-week-starting-week)
+      (floor-quotient
+        (- (date-year-day date)
+           1
+           (priv:days-before-first-week date day-of-week-starting-week))
+        7))
+
+    ;; ====================
+    ;; Time/Date/Julian Day/Modified Julian Day Converters
+    ;; ====================
+
+    ;; TODO
+
+    ;; ====================
+    ;; Date to String/String to Date Converters
+    ;; ====================
+
+    (define (priv:locale-abbr-weekday n)
+      (vector-ref priv:LOCALE-ABBR-WEEKDAY-VECTOR n))
+    (define (priv:locale-long-weekday n)
+      (vector-ref priv:LOCALE-LONG-WEEKDAY-VECTOR n))
+    (define (priv:locale-abbr-month n)
+      (vector-ref priv:LOCALE-ABBR-MONTH-VECTOR n))
+    (define (priv:locale-long-month n)
+      (vector-ref priv:LOCALE-LONG-MONTH-VECTOR n))
+
+    (define (priv:padding n pad-with len)
+      (let* ((str     (number->string n))
+             (str-len (string-length str)))
+        (cond
+          ((or (> str-len len) (not pad-with)) str)
+          (else (string-pad str len pad-with)))))
+
+    (define (priv:locale-am/pm hr)
+      (if (> hr 11) priv:LOCALE-PM priv:LOCALE-AM))
+
+    (define (priv:date-week-number-iso date)
+      (let* ((year (date-year date))
+             (yday (date-year-day date))
+             (jan1-wday (priv:week-day 1 1 year))
+             ;; 可能为0或53+
+             (raw-week (+ (quotient (+ yday jan1-wday -2) 7)
+                          (if (> jan1-wday 4) 0 1))))
+
+        (cond ((<= raw-week 0)
+               ;; 归前一年：判断前一年52周还是53周（周四年首=53周）
+               (if (> (priv:week-day 1 1 (- year 1)) 4) 52 53))
+              ((and (= raw-week 53)
+                    (<= (priv:week-day 1 1 (+ year 1)) 4))
+               ;; 归下一年第1周
+               1)
+
+              (else raw-week))))
+
+    (define (priv:last-n-digits i n)
+      (modulo i (expt 10 n)))
+
+    (define (priv:tz-printer offset port)
+      (cond
+        ((zero? offset)     (display "Z" port))
+        ((negative? offset) (display "-" port))
+        (else               (display "+" port)))
+      (unless (zero? offset)
+        (let ((hours   (abs (quotient offset (* 60 60))))
+              (minutes (abs (quotient (remainder offset (* 60 60)) 60))))
+          (display (priv:padding hours   #\0 2) port)
+          (display (priv:padding minutes #\0 2) port))))
+
+    (define (priv:directives/formatter char format-string)
+      (lambda (date pad-with port)
+        (case char
+          ((#\~) (display #\~ port))
+          ((#\a) (display (priv:locale-abbr-weekday (date-week-day date))
+                          port))
+          ((#\A) (display (priv:locale-long-weekday (date-week-day date))
+                          port))
+          ((#\b #\h) (display (priv:locale-abbr-month (date-month date))
+                              port))
+          ((#\B) (display (priv:locale-long-month (date-month date))
+                          port))
+          ((#\c) (display (date->string date priv:LOCALE-DATE-TIME-FORMAT)
+                          port))
+          ((#\d) (display (priv:padding (date-day date) #\0 2)
+                          port))
+          ((#\D) (display (date->string date "~m/~d/~y")
+                          port))
+          ((#\e) (display (priv:padding (date-day date) #\space 2)
+                          port))
+          ;; ref Guile
+          ((#\f) (receive (s ns)
+                          (floor/ (+ (* (date-second date) priv:NANO)
+                                     (date-nanosecond date))
+                                  priv:NANO)
+                   (display (number->string s) port)
+                   (display priv:LOCALE-DECIMAL-POINT port)
+                   (let ((str (priv:padding ns #\0 9)))
+                     (display (substring str 0 1) port)
+                     (display (string-trim-right str #\0 1) port))))
+          ((#\H) (display (priv:padding (date-hour date)
+                                        pad-with 2)
+                          port))
+          ((#\I) (let* ((hr  (date-hour date))
+                        (hr* (if (> hr 12) (- hr 12) hr)))
+                   (display (priv:padding hr* pad-with 2)
+                            port)))
+          ((#\j) (display (priv:padding (date-year-day date)
+                                        pad-with 3)
+                          port))
+          ((#\k) (display (priv:padding (date-hour date)
+                                        #\space 2)
+                          port))
+          ((#\l) (let* ((hr  (date-hour date))
+                        (hr* (if (> hr 12) (- hr 12) hr)))
+                   (display (priv:padding hr* #\space 2)
+                            port)))
+          ((#\m) (display (priv:padding (date-month date)
+                                        pad-with 2)
+                          port))
+          ((#\M) (display (priv:padding (date-minute date)
+                                        pad-with 2)
+                          port))
+          ((#\n) (newline port))
+          ((#\N) (display (priv:padding (date-nanosecond date)
+                                        pad-with 9)
+                          port))
+          ((#\p) (display (priv:locale-am/pm (date-hour date)) port))
+          ((#\r) (display (date->string date "~I:~M:~S ~p") port))
+
+          ((#\s) (error "Not Implement"))
+          ((#\S) (let ((sec-delta (if (> (date-nanosecond date) priv:NANO)
+                                    1 0)))
+                   (display (priv:padding (+ (date-second date) sec-delta)
+                                          pad-with 2)
+                            port)))
+
+          ((#\t) (display #\tab port))
+          ((#\T) (display (date->string date "~H:~M:~S") port))
+          ((#\U) (let* ((week>0?   (> (priv:days-before-first-week date 0) 0))
+                        (week-num  (date-week-number date 0))
+                        (week-num* (if week>0? (+ week-num 1) week-num)))
+                   (display (priv:padding week-num* #\0 2) port)))
+
+          ((#\V) (display (priv:padding (priv:date-week-number-iso date)
+                                        #\0 2) port))
+          ((#\w) (display (date-week-day date) port))
+          ((#\W) (let* ((week>1?   (> (priv:days-before-first-week date 1) 0))
+                        (week-num  (date-week-number date 1))
+                        (week-num* (if week>1? (+ week-num 1) week-num)))
+                   (display (priv:padding week-num* #\0 2) port)))
+          ((#\x) (display (date->string date priv:LOCALE-SHORT-DATE-FORMAT) port))
+          ((#\X) (display (date->string date priv:LOCALE-TIME-FORMAT) port))
+          ((#\y) (display (priv:padding (priv:last-n-digits (date-year date) 2)
+                                        pad-with 2)
+                          port))
+          ((#\Y) (display (priv:padding (date-year date) pad-with 4)
+                          port))
+          ((#\z) (priv:tz-printer (date-zone-offset date) port))
+          ((#\Z) (error "Not Implement"))
+          ((#\1) (display (date->string date "~Y-~m-~d") port))
+          ((#\2) (display (date->string date "~H:~M:~S~z") port))
+          ((#\3) (display (date->string date "~H:~M:~S") port))
+          ((#\4) (display (date->string date "~Y-~m-~dT~H:~M:~S~z") port))
+          ((#\5) (display (date->string date "~Y-~m-~dT~H:~M:~S") port))
+          (else (priv:bad-format-error format-string)))))
+
+    (define (priv:bad-format-error format-string)
+      (value-error "bad date format string" format-string))
+
+    (define (priv:date-printer date format-string format-string-port port)
+      (let ((current-char (read-char format-string-port))
+            (pad-char     (peek-char format-string-port)))
+        (cond
+          ((eof-object? current-char) (values))
+
+          ((and (eof-object? pad-char)
+                ;; unfinished directives
+                (char=? current-char #\~))
+           (priv:bad-format-error format-string))
+
+          ((and (char=? current-char #\~)
+                (or (char=? pad-char #\-) (char=? pad-char #\_)))
+           (let ((pad-pad-char (begin (read-char format-string-port)
+                                      (peek-char format-string-port))))
+             (if (eof-object? pad-pad-char)
+               (priv:bad-format-error format-string)
+               (let ((formatter (priv:directives/formatter pad-pad-char format-string))
+                     (pad-with  (if (char=? pad-char #\-) #f #\space)))
+                 (begin (formatter date pad-with port)
+                        (priv:date-printer date format-string
+                                           format-string-port port))))))
+
+          ((char=? current-char #\~)
+           (let ((formatter (priv:directives/formatter pad-char format-string)))
+             (begin (formatter date #\0 port)
+                    (read-char format-string-port) ; consume
+                    (priv:date-printer date format-string
+                                       format-string-port port))))
+
+          (else
+            (display current-char port)
+            (priv:date-printer date format-string
+                               format-string-port port)))))
+
+    (define* (date->string date (format-string "~c"))
+      (let ((str-port (open-output-string)))
+        (priv:date-printer date format-string
+                   (open-input-string format-string)
+                   str-port)
+        (get-output-string str-port)))))
diff --git a/src/goldfish.hpp b/src/goldfish.hpp
index 94b05afa..cbc1c6f6 100644
--- a/src/goldfish.hpp
+++ b/src/goldfish.hpp
@@ -404,26 +404,60 @@ glue_goldfish (s7_scheme* sc) {
              s7_make_typed_function (sc, s_delete_file, f_delete_file, 1, 0, false, d_delete_file, NULL));
 }
 
+// old `f_current_second` TODO: use std::chrono::tai_clock::now() when using C++ 20
+//                        NOTE(jinser): use a new name for tai
+// `current-second` impl by g_get-time-of-day now
 static s7_pointer
-f_current_second (s7_scheme* sc, s7_pointer args) {
-  // TODO: use std::chrono::tai_clock::now() when using C++ 20
-  tb_timeval_t tp= {0};
-  tb_gettimeofday (&tp, tb_null);
-  s7_double res= (time_t) tp.tv_sec + (tp.tv_usec / 1000000.0);
-  return s7_make_real (sc, res);
+f_get_time_of_day (s7_scheme* sc, s7_pointer args) {
+  using namespace std::chrono;
+  auto now = time_point_cast<microseconds>(system_clock::now());
+  auto since_epoch = now.time_since_epoch();
+  auto sec = duration_cast<seconds>(since_epoch);
+
+  s7_pointer vs = s7_list(sc, 2,
+                          s7_make_integer(sc, sec.count()),
+                          s7_make_integer(sc, (since_epoch - sec).count()));
+  return s7_values(sc, vs);
+}
+
+static s7_pointer
+f_monotonic_nanosecond (s7_scheme* sc, s7_pointer args) {
+  using namespace std::chrono;
+  auto now = steady_clock::now();
+  auto duration = now.time_since_epoch();
+  auto count = duration_cast<std::chrono::nanoseconds>(duration).count();
+  return s7_make_integer(sc, count);
+}
+
+template<typename Clock>
+constexpr int64_t clock_resolution_ns() {
+  typedef std::chrono::duration<double, std::nano> NS;
+  NS ns = typename Clock::duration(1);
+  return ns.count();
 }
 
 inline void
 glue_scheme_time (s7_scheme* sc) {
   s7_pointer cur_env= s7_curlet (sc);
 
-  const char* s_current_second= "g_current-second";
-  const char* d_current_second= "(g_current-second): () => double, return the "
-                                "current unix timestamp in double";
-  s7_define (sc, cur_env, s7_make_symbol (sc, s_current_second),
-             s7_make_typed_function (sc, s_current_second, f_current_second, 0, 0, false, d_current_second, NULL));
+  const char* s_get_time_of_day= "g_get-time-of-day";
+  const char* d_get_time_of_day= "(g_get-time-of-day): () => (integer, integer), return the "
+                                "current second and microsecond in integer";
+  s7_define (sc, cur_env, s7_make_symbol (sc, s_get_time_of_day),
+             s7_make_typed_function (sc, s_get_time_of_day, f_get_time_of_day, 0, 0, false, d_get_time_of_day, NULL));
+
+  const char* s_monotonic_nanosecond= "g_monotonic-nanosecond";
+  const char* d_monotonic_nanosecond= "(g_monotonic-nanosecond): () => integer, TODO";
+  s7_define (sc, cur_env, s7_make_symbol (sc, s_monotonic_nanosecond),
+             s7_make_typed_function (sc, s_monotonic_nanosecond, f_monotonic_nanosecond, 0, 0, false, d_monotonic_nanosecond, NULL));
+
+  s7_define_constant_with_environment (sc, cur_env, "g_system-clock-resolution",
+                                       s7_make_integer(sc, clock_resolution_ns<std::chrono::system_clock>()));
+  s7_define_constant_with_environment (sc, cur_env, "g_steady-clock-resolution",
+                                       s7_make_integer(sc, clock_resolution_ns<std::chrono::steady_clock>()));
 }
 
+
 static s7_pointer
 f_get_environment_variable (s7_scheme* sc, s7_pointer args) {
 #ifdef _MSC_VER
diff --git a/tests/goldfish/liii/time-test.scm b/tests/goldfish/liii/time-test.scm
index bb44b0d0..86e5b1c9 100644
--- a/tests/goldfish/liii/time-test.scm
+++ b/tests/goldfish/liii/time-test.scm
@@ -17,7 +17,9 @@
 (import (liii check)
         (liii time)
         (scheme time)
-        (liii base))
+        (liii base)
+        (srfi srfi-1)
+        (srfi srfi-19))
 
 (check-set-mode! 'report-failed)
 
@@ -179,4 +181,615 @@ integer?
 (check (integer? (jiffies-per-second)) => #t)
 (check (positive? (jiffies-per-second)) => #t)
 
+;; ====================
+;; SRFI-19: Time Data Types and Procedures
+;; ====================
+
+;; ====================
+;; Constants
+;; ====================
+
+#|
+TIME-DURATION TIME-MONOTONIC TIME-PROCESS TIME-TAI TIME-THREAD TIME-UTC
+时间类型常量，用于标识不同类型的时间。
+
+说明
+----
+这些常量表示不同的时钟类型：
+- TIME-DURATION : 时间间隔（无起始点）
+- TIME-MONOTONIC: 单调递增的时钟（不受系统时间调整影响）
+- TIME-PROCESS  : 进程使用的CPU时间
+- TIME-TAI      : 国际原子时
+- TIME-THREAD   : 线程使用的CPU时间
+- TIME-UTC      : 协调世界时
+
+每个常量对应一个唯一的符号值，用于指定时间对象的类型。
+|#
+
+;; Test time constants
+(check-true (symbol? TIME-DURATION))
+(check-true (symbol? TIME-MONOTONIC))
+(check-true (symbol? TIME-PROCESS))
+(check-true (symbol? TIME-TAI))
+(check-true (symbol? TIME-THREAD))
+(check-true (symbol? TIME-UTC))
+
+;; Ensure all constants are distinct
+(let ((constants (list TIME-DURATION TIME-MONOTONIC TIME-PROCESS
+                       TIME-TAI TIME-THREAD TIME-UTC)))
+  (check-true (= (length constants) (length (delete-duplicates constants)))))
+
+;; ====================
+;; Time object and accessors
+;; ====================
+
+#|
+make-time
+创建时间对象。
+
+语法
+----
+(make-time type nanosecond second)
+
+参数
+----
+type : symbol?
+时间类型，必须是时间类型常量之一。
+
+nanosecond : integer?
+纳秒部分，必须在 0-999999999 范围内（包含边界）。
+
+second : integer?
+秒部分，可以是任意整数。
+
+返回值
+-----
+time?
+一个新的时间对象。
+
+错误处理
+--------
+wrong-type-arg
+当参数类型不正确时抛出错误。
+|#
+
+;; Test make-time
+(check-true (time? (make-time TIME-UTC 0 0)))
+(check-true (time? (make-time TIME-MONOTONIC 500000000 1234567890)))
+(check-true (time? (make-time TIME-TAI 999999999 -1234567890)))
+
+;; Test error conditions
+(check-catch 'value-error    (make-time 'invalid-type 0 0))
+(check-catch 'wrong-type-arg (make-time TIME-UTC 'not-number 0))
+(check-catch 'wrong-type-arg (make-time TIME-UTC 0 'not-number))
+
+#|
+time?
+判断对象是否为时间对象。
+
+语法
+----
+(time? obj)
+
+参数
+----
+obj : any?
+任意对象。
+
+返回值
+-----
+boolean?
+如果obj是时间对象则返回#t，否则返回#f。
+|#
+
+;; Test time?
+(check-true  (time? (make-time TIME-UTC 0 0)))
+(check-false (time? 123))
+(check-false (time? "string"))
+(check-false (time? 'symbol))
+(check-false (time? #t))
+(check-false (time? #(vector)))
+(check-false (time? (cons 1 2)))
+
+#|
+time-type time-nanosecond time-second
+获取时间对象的组成部分。
+
+语法
+----
+(time-type time)
+(time-nanosecond time)
+(time-second time)
+
+参数
+----
+time : time?
+时间对象。
+
+返回值
+-----
+time-type : symbol?
+时间类型。
+
+time-nanosecond : integer?
+纳秒部分（0-999999999）。
+
+time-second : integer?
+秒部分。
+
+错误处理
+--------
+wrong-type-arg
+当参数不是时间对象时抛出错误。
+|#
+
+;; Test time accessors
+(let ((t1 (make-time TIME-UTC 123456789 987654321))
+      (t2 (make-time TIME-MONOTONIC 999999999 0))
+      (t3 (make-time TIME-TAI 0 -1234567890)))
+  (check (time-type t1) => TIME-UTC)
+  (check (time-nanosecond t1) => 123456789)
+  (check (time-second t1) => 987654321)
+
+  (check (time-type t2) => TIME-MONOTONIC)
+  (check (time-nanosecond t2) => 999999999)
+  (check (time-second t2) => 0)
+
+  (check (time-type t3) => TIME-TAI)
+  (check (time-nanosecond t3) => 0)
+  (check (time-second t3) => -1234567890))
+
+;; Test error conditions
+(check-catch 'wrong-type-arg (time-type "not-a-time"))
+(check-catch 'wrong-type-arg (time-nanosecond 123))
+(check-catch 'wrong-type-arg (time-second 'symbol))
+
+#|
+set-time-type! set-time-nanosecond! set-time-second!
+设置时间对象的组成部分。
+
+语法
+----
+(set-time-type! time type)
+(set-time-nanosecond! time nanosecond)
+(set-time-second! time second)
+
+参数
+----
+time : time?
+要修改的时间对象。
+
+type : symbol?
+新的时间类型，必须是时间类型常量之一。
+
+nanosecond : integer?
+新的纳秒部分。
+
+second : integer?
+新的秒部分。
+
+返回值
+-----
+any?
+返回被设定的新值。
+
+错误处理
+--------
+wrong-type-arg
+当参数类型不正确时抛出错误。
+|#
+
+;; Test set-time-*! procedures
+(let ((t (make-time TIME-UTC 0 0)))
+  (check (set-time-type! t TIME-MONOTONIC)  => TIME-MONOTONIC)
+  (check (set-time-nanosecond! t 555555555) => 555555555)
+  (check (set-time-second! t 1234567890)    => 1234567890)
+
+  (check (time-type t) => TIME-MONOTONIC)
+  (check (time-nanosecond t) => 555555555)
+  (check (time-second t) => 1234567890))
+
+;; Test error conditions for set-time-*!
+(let ((t (make-time TIME-UTC 0 0)))
+  (check-catch 'wrong-type-arg (set-time-type! "not-a-time" TIME-MONOTONIC))
+  ;; no check
+  (check (set-time-type! t 'invalid-type) => 'invalid-type)
+  (check-catch 'wrong-type-arg (set-time-nanosecond! "not-a-time" 0))
+  (check-catch 'wrong-type-arg (set-time-second! "not-a-time" 0)))
+
+
+#|
+copy-time
+复制时间对象。
+
+语法
+----
+(copy-time time)
+
+参数
+----
+time : time?
+要复制的时间对象。
+
+返回值
+-----
+time?
+一个新的时间对象，其值与原时间对象相同但独立。
+
+错误处理
+--------
+wrong-type-arg
+当参数不是时间对象时抛出错误。
+|#
+
+;; Test copy-time
+(let* ((original (make-time TIME-TAI 777777777 888888888))
+       (copied (copy-time original)))
+  (check-true (time? copied))
+  (check (time-type copied) => (time-type original))
+  (check (time-nanosecond copied) => (time-nanosecond original))
+  (check (time-second copied) => (time-second original))
+  ;; Ensure it's a copy, not the same object
+  (check-false (eq? original copied))
+  ;; Modify original and ensure copy is unchanged
+  (set-time-nanosecond! original 999999999)
+  (check (time-nanosecond copied) => 777777777))
+
+;; Test error conditions
+(check-catch 'wrong-type-arg (copy-time "not-a-time"))
+
+;; ====================
+;; Current time and clock resolution
+;; ====================
+
+#|
+current-time
+获取当前时间。
+
+语法
+----
+(current-time [clock-type])
+
+参数
+----
+clock-type : symbol? (可选)
+时钟类型，默认为 TIME-UTC。必须是时间类型常量之一。
+
+返回值
+-----
+time?
+当前时间的时间对象。
+
+错误处理
+--------
+wrong-type-arg
+当clock-type不是有效的时间类型常量时抛出错误。
+|#
+
+;; Test current-time
+(check-true (time? (current-time)))
+(check-true (time? (current-time TIME-UTC)))
+(check-true (time? (current-time TIME-MONOTONIC)))
+(check-true (time? (current-time TIME-TAI)))
+(check-catch 'wrong-type-arg (time? (current-time TIME-THREAD)))
+(check-catch 'wrong-type-arg (time? (current-time TIME-PROCESS)))
+(check-catch 'wrong-type-arg (time? (current-time TIME-DURATION)))
+
+;; Check that returned times have correct types
+(check (time-type (current-time TIME-UTC))       => TIME-UTC)
+(check (time-type (current-time TIME-MONOTONIC)) => TIME-MONOTONIC)
+(check (time-type (current-time TIME-TAI))       => TIME-TAI)
+(check-catch 'wrong-type-arg (time-type (current-time TIME-THREAD)))
+(check-catch 'wrong-type-arg (time-type (current-time TIME-PROCESS)))
+(check-catch 'wrong-type-arg (time-type (current-time TIME-DURATION)))
+
+;; Check that nanoseconds are in valid range
+(let ((t (current-time)))
+  (check-true (>= (time-nanosecond t) 0))
+  (check-true (<= (time-nanosecond t) 999999999)))
+
+;; Test monotonic time increases
+(let ((t1 (current-time TIME-MONOTONIC))
+      (t2 (current-time TIME-MONOTONIC)))
+  (check-true (or (> (time-second t2) (time-second t1))
+                  (and (= (time-second t2) (time-second t1))
+                       (>= (time-nanosecond t2) (time-nanosecond t1))))))
+
+;; Test error conditions
+(check-catch 'wrong-type-arg (current-time 'invalid-type))
+;
+#|
+time-resolution
+获取时钟分辨率。
+
+语法
+----
+(time-resolution [clock-type])
+
+参数
+----
+clock-type : symbol? (可选)
+时钟类型，默认为 TIME-UTC。必须是时间类型常量之一。
+
+返回值
+-----
+integer?
+一个纳秒（nanosecond）整数，表示指定时钟的分辨率（精度）。
+
+说明
+----
+返回值表示该时钟能区分的最小时间间隔。
+例如，如果分辨率为1000000，那么纳秒部分可能是1000000的倍数。
+
+错误处理
+--------
+wrong-type-arg
+当clock-type不是有效的时间类型常量时抛出错误。
+|#
+
+;; Test time-resolution
+(check-true (integer? (time-resolution)))
+(check-true (integer? (time-resolution TIME-UTC)))
+(check-true (integer? (time-resolution TIME-MONOTONIC)))
+(check-true (integer? (time-resolution TIME-TAI)))
+(check-catch 'wrong-type-arg (time-resolution TIME-THREAD))
+(check-catch 'wrong-type-arg (time-resolution TIME-PROCESS))
+(check-catch 'wrong-type-arg (time-resolution TIME-DURATION))
+
+;; Test error conditions
+(check-catch 'wrong-type-arg (time-resolution 'invalid-type))
+
+;; ====================
+;; Date object and accessors
+;; ====================
+
+#|
+make-date
+创建日期对象。
+
+语法
+----
+(make-date nanosecond second minute hour day month year zone-offset)
+
+参数
+----
+nanosecond : integer?
+
+second : integer?
+
+minute : integer?
+
+hour : integer?
+
+day : integer?
+
+month : integer?
+
+year : integer?
+
+zone-offset : integer?
+
+返回值
+-----
+date?
+一个新的日期对象。
+
+错误处理
+--------
+wrong-type-arg
+当参数类型不正确时抛出错误。
+|#
+
+;; Test make-date
+(check-true (date? (make-date 0 0 0 0 1 1 1970 0)))
+(check-true (date? (make-date 999999999 59 59 23 31 12 2023 28800)))
+(check-true (date? (make-date 500000000 30 30 12 15 6 2000 -14400)))
+
+;; Test edge cases
+(check-true (date? (make-date 0 0 0 0 1 1 0 0)))          ; Year 0
+(check-true (date? (make-date 0 0 0 0 1 1 -1000 0)))      ; Year -1000
+(check-true (date? (make-date 0 0 0 0 1 1 10000 0)))      ; Year 10000
+(check-true (date? (make-date 0 0 0 0 1 1 2023 -64800)))  ; Min zone offset
+(check-true (date? (make-date 0 0 0 0 1 1 2023 64800)))   ; Max zone offset
+
+;; Test error conditions
+(check-catch 'wrong-type-arg (make-date 'not-number 0 0 0 1 1 1970 0))
+;; no range check
+(check-true (date? (make-date -1 0 0 0 1 1 1970 0)))
+(check-true (date? (make-date 1000000000 0 0 0 1 1 1970 0)))
+
+#|
+date?
+判断对象是否为日期对象。
+
+语法
+----
+(date? obj)
+
+参数
+----
+obj : any?
+任意对象。
+
+返回值
+-----
+boolean?
+如果obj是日期对象则返回#t，否则返回#f。
+|#
+
+;; Test date?
+(check-true  (date? (make-date 0 0 0 0 1 1 1970 0)))
+(check-false (date? 123))
+(check-false (date? "string"))
+(check-false (date? 'symbol))
+(check-false (date? #t))
+(check-false (date? #(vector)))
+(check-false (date? (cons 1 2)))
+(check-false (date? (make-time TIME-UTC 0 0)))
+
+#|
+date-nanosecond date-second date-minute date-hour
+date-day date-month date-year date-zone-offset
+获取日期对象的组成部分。
+
+语法
+----
+(date-nanosecond date)
+(date-second date)
+(date-minute date)
+(date-hour date)
+(date-day date)
+(date-month date)
+(date-year date)
+(date-zone-offset date)
+
+参数
+----
+date : date?
+日期对象。
+
+返回值
+-----
+date-nanosecond : integer?
+
+date-second : integer?
+
+date-minute : integer?
+
+date-hour : integer?
+
+date-day : integer?
+
+date-month : integer?
+
+date-year : integer?
+
+date-zone-offset : integer?
+
+错误处理
+--------
+wrong-type-arg
+当参数不是日期对象时抛出错误。
+|#
+
+;; Test date accessors
+(let ((d (make-date 123456789 45 30 14 25 12 2023 28800)))
+  (check (date-nanosecond d) => 123456789)
+  (check (date-second d) => 45)
+  (check (date-minute d) => 30)
+  (check (date-hour d) => 14)
+  (check (date-day d) => 25)
+  (check (date-month d) => 12)
+  (check (date-year d) => 2023)
+  (check (date-zone-offset d) => 28800))
+
+;; Test with different values
+(let ((d (make-date 999999999 59 59 23 31 1 2000 -14400)))
+  (check (date-nanosecond d) => 999999999)
+  (check (date-second d) => 59)
+  (check (date-minute d) => 59)
+  (check (date-hour d) => 23)
+  (check (date-day d) => 31)
+  (check (date-month d) => 1)
+  (check (date-year d) => 2000)
+  (check (date-zone-offset d) => -14400))
+
+;; Test error conditions
+(check-catch 'wrong-type-arg (date-nanosecond "not-a-date"))
+(check-catch 'wrong-type-arg (date-second 123))
+(check-catch 'wrong-type-arg (date-minute 'symbol))
+(check-catch 'wrong-type-arg (date-hour #t))
+(check-catch 'wrong-type-arg (date-day #(vector)))
+(check-catch 'wrong-type-arg (date-month (cons 1 2)))
+;; FIXME: strange?
+(check-true  (undefined? (date-year (make-time TIME-UTC 0 0))))
+(check-catch 'wrong-type-arg (date-zone-offset #f))
+
+;; ====================
+;; Date to String/String to Date Converters
+;; ====================
+
+#|
+date->string
+将日期对象转换为字符串。
+
+语法
+----
+(date->string date [format-string])
+
+参数
+----
+date : date?
+要转换的日期对象。
+
+format-string : string? (可选)
+格式字符串，默认为 "~c"（区域设置的日期和时间格式）。
+
+返回值
+-----
+string?
+表示日期的字符串。
+
+说明
+----
+格式字符串使用类似C的strftime格式说明符，但以~开头。
+常见格式说明符：
+  ~a : 缩写的星期几名称
+  ~A : 完整的星期几名称
+  ~b : 缩写的月份名称
+  ~B : 完整的月份名称
+  ~c : 区域设置的日期和时间表示
+  ~d : 月份中的日（01-31）
+  ~H : 24小时制的小时（00-23）
+  ~I : 12小时制的小时（01-12）
+  ~m : 月份（01-12）
+  ~M : 分钟（00-59）
+  ~p : 区域设置的上午/下午指示符
+  ~S : 秒（00-60）
+  ~y : 不带世纪的年份（00-99）
+  ~Y : 带世纪的年份
+  ~z : 时区偏移（+HHMM或-HHMM）
+  ~Z : 时区名称或缩写
+  ~~ : 字面量的~
+参考：https://srfi.schemers.org/srfi-19/srfi-19.html#:~:text=Table%201,-%3A%20DATE
+|#
+
+;; Test date->string
+(let ((d (make-date 0 0 0 0 1 1 1970 0)))  ; Unix epoch in UTC
+  (check (date->string d)            => "Thu Jan 01 00:00:00Z 1970")
+  (check (date->string d "~Y-~m-~d") => "1970-01-01")
+  (check (date->string d "~H:~M:~S") => "00:00:00"))
+
+;; Test with different dates
+(let ((d1 (make-date 500000000 30 15 9 4 7 1776 0))          ; US Independence
+      (d2 (make-date 123456789 45 30 14 25 12 2023 28800))   ; Christmas in UTC+8
+      (d3 (make-date 999999999 59 59 23 31 12 1999 -18000))) ; Y2K in UTC-5
+  (check (date->string d1)                             => "Thu Jul 04 09:15:30Z 1776")
+  (check (date->string d2 "~Y-~m-~d ~H:~M:~S")         => "2023-12-25 14:30:45")
+  (check (date->string d3 "~A, ~B ~d, ~Y ~I:~M:~S ~p") => "Friday, December 31, 1999 11:59:59 PM"))
+
+;; Test format specifiers
+(let ((d (make-date 123456789 45 30 14 25 12 2023 28800)))
+  ;; Basic numeric formats
+  (check (date->string d "~Y-~m-~d ~H:~M:~S") => "2023-12-25 14:30:45")
+
+  ;; Test literal ~
+  (check (date->string d "~~") => "~")
+
+  ;; Test combination of specifiers and literals
+  (check (date->string d "Date: ~Y/~m/~d Time: ~H:~M") => "Date: 2023/12/25 Time: 14:30")
+
+  ;; Test CJK
+  (check (date->string d "~Y年，第~V週。~H시~M분") => "2023年，第52週。14시30분"))
+
+;; Test error conditions
+(let ((d (make-date 0 0 0 0 1 1 1970 0)))
+  (check-catch 'wrong-type-arg (date->string "not-a-date"))
+  (check-catch 'wrong-type-arg (date->string d 123))  ; format-string not a string
+  (check-catch 'wrong-type-arg (date->string d 'symbol)))
+
+;; Test that current date can be converted
+(check-catch 'todo (string? (date->string (current-date))))
+(check-catch 'todo (string? (date->string (current-date) "~Y年~m月~d日 ~H时~M分~S秒")))
+
 (check-report)

From fef67bee703a5e0aad9cd61a27772f9f05da019f Mon Sep 17 00:00:00 2001
From: Jinser Kafka <aimer@purejs.icu>
Date: Fri, 30 Jan 2026 17:29:05 +0800
Subject: [PATCH 02/15] docs(devel): add 210_10

---
 devel/210_10.md | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 devel/210_10.md

diff --git a/devel/210_10.md b/devel/210_10.md
new file mode 100644
index 00000000..c4970ad6
--- /dev/null
+++ b/devel/210_10.md
@@ -0,0 +1,33 @@
+# [210_10] `(srfi srfi-19)`
+
+## 任务相关的代码文件
+- `src/goldfish.hpp`
+- `tests/goldfish/liii/time-test.scm`
+- `goldfish/scheme/time.scm`
+- `goldfish/srfi/srfi-19.scm`
+
+## 如何测试
+
+```shell
+# 可能需要清除缓存
+# rm .xmake/ build/ -r
+xmake f -vyD
+xmake b goldfish
+./bin/goldfish tests/goldfish/liii/time-test.scm
+```
+
+## 2026/1/30 初始化 time 和 date 结构
+
+### What
+
+1. 新增 glue：`g_gettimeofday`, `g_monotonic-nanosecond`, `g_steady-clock-resolution`, `g_system-clock-resolution`
+2. 实现 time 与 date 基本结构
+3. 实现部分 SRFI-19 proc，包括 `current-time`, `date->string` 等
+
+### Why
+
+扩充时间与日期的支持。
+
+### How
+
+通过 C++17 的 chrono 绑定实现。

From 6b21b829c1d5950d6ece7f92173787f3905dad59 Mon Sep 17 00:00:00 2001
From: Jinser Kafka <aimer@purejs.icu>
Date: Fri, 30 Jan 2026 17:31:22 +0800
Subject: [PATCH 03/15] docs(devel): 210_10 -> 210_11

---
 devel/{210_10.md => 210_11.md} | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
 rename devel/{210_10.md => 210_11.md} (96%)

diff --git a/devel/210_10.md b/devel/210_11.md
similarity index 96%
rename from devel/210_10.md
rename to devel/210_11.md
index c4970ad6..789af6ee 100644
--- a/devel/210_10.md
+++ b/devel/210_11.md
@@ -1,4 +1,4 @@
-# [210_10] `(srfi srfi-19)`
+# [210_11] `(srfi srfi-19)`
 
 ## 任务相关的代码文件
 - `src/goldfish.hpp`

From b0c90a4e189165d047992978083b6a8ad69279d4 Mon Sep 17 00:00:00 2001
From: Jinser Kafka <aimer@purejs.icu>
Date: Fri, 30 Jan 2026 17:32:08 +0800
Subject: [PATCH 04/15] docs(devel): 210_11 -> 210_12

---
 devel/{210_11.md => 210_12.md} | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
 rename devel/{210_11.md => 210_12.md} (96%)

diff --git a/devel/210_11.md b/devel/210_12.md
similarity index 96%
rename from devel/210_11.md
rename to devel/210_12.md
index 789af6ee..274cd3af 100644
--- a/devel/210_11.md
+++ b/devel/210_12.md
@@ -1,4 +1,4 @@
-# [210_11] `(srfi srfi-19)`
+# [210_12] `(srfi srfi-19)`
 
 ## 任务相关的代码文件
 - `src/goldfish.hpp`

From 3046b375de75bd52f99b09a8cd6744dce4aabfa3 Mon Sep 17 00:00:00 2001
From: Jinser Kafka <aimer@purejs.icu>
Date: Fri, 30 Jan 2026 23:28:41 +0800
Subject: [PATCH 05/15] fix(srfi-19): import (liii error)

---
 goldfish/srfi/srfi-19.scm | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/goldfish/srfi/srfi-19.scm b/goldfish/srfi/srfi-19.scm
index 38bec21b..d098b9e8 100644
--- a/goldfish/srfi/srfi-19.scm
+++ b/goldfish/srfi/srfi-19.scm
@@ -50,7 +50,8 @@
   (import (rename (scheme time)
                   (get-time-of-day      glue:get-time-of-day)
                   (monotonic-nanosecond glue:monotonic-nanosecond))
-          (only (srfi srfi-13) string-pad string-tokenize string-trim-right))
+          (only (srfi srfi-13) string-pad string-tokenize string-trim-right)
+          (liii error))
   (export
     ;; Constants
     TIME-DURATION TIME-MONOTONIC TIME-PROCESS

From b5456ac3d74b1dcf7fd7034faf5cb47b14180e94 Mon Sep 17 00:00:00 2001
From: jinser <aimer@purejs.icu>
Date: Mon, 2 Feb 2026 22:01:31 +0800
Subject: [PATCH 06/15] Apply suggestions from code review

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 devel/210_12.md           | 2 +-
 goldfish/srfi/srfi-19.scm | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/devel/210_12.md b/devel/210_12.md
index 274cd3af..6b8feeb3 100644
--- a/devel/210_12.md
+++ b/devel/210_12.md
@@ -20,7 +20,7 @@ xmake b goldfish
 
 ### What
 
-1. 新增 glue：`g_gettimeofday`, `g_monotonic-nanosecond`, `g_steady-clock-resolution`, `g_system-clock-resolution`
+1. 新增 glue：`g_get-time-of-day`, `g_monotonic-nanosecond`, `g_steady-clock-resolution`, `g_system-clock-resolution`
 2. 实现 time 与 date 基本结构
 3. 实现部分 SRFI-19 proc，包括 `current-time`, `date->string` 等
 
diff --git a/goldfish/srfi/srfi-19.scm b/goldfish/srfi/srfi-19.scm
index d098b9e8..fa4f5973 100644
--- a/goldfish/srfi/srfi-19.scm
+++ b/goldfish/srfi/srfi-19.scm
@@ -219,7 +219,7 @@
         (cond
           ((null? table)       10) ; 理论值
           ((>= s (caar table)) (cdar table))
-          (else                (loop (cdr table))))))
+          (else                (lp (cdr table))))))
 
     (define (priv:current-time-monotonic)
       (receive (s ns) (floor/ (glue:monotonic-nanosecond) 1000000000) ; 1e9

From 078218b5fa5811bbf7170b0f85ebab4c5551f30d Mon Sep 17 00:00:00 2001
From: Jinser Kafka <aimer@purejs.icu>
Date: Fri, 6 Feb 2026 17:50:38 +0800
Subject: [PATCH 07/15] fix(srfi-19): ~I format

---
 goldfish/srfi/srfi-19.scm | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/goldfish/srfi/srfi-19.scm b/goldfish/srfi/srfi-19.scm
index fa4f5973..e28cc2dc 100644
--- a/goldfish/srfi/srfi-19.scm
+++ b/goldfish/srfi/srfi-19.scm
@@ -451,10 +451,10 @@
           ((#\H) (display (priv:padding (date-hour date)
                                         pad-with 2)
                           port))
-          ((#\I) (let* ((hr  (date-hour date))
-                        (hr* (if (> hr 12) (- hr 12) hr)))
-                   (display (priv:padding hr* pad-with 2)
-                            port)))
+          ((#\I) (display (priv:padding (+ 1 (modulo (- (date-hour date) 1) 12))
+                                        pad-with
+                                        2)
+                          port))
           ((#\j) (display (priv:padding (date-year-day date)
                                         pad-with 3)
                           port))

From cfc6efb4b2926dc3ebccd23f3b12228e78cdcf71 Mon Sep 17 00:00:00 2001
From: Jinser Kafka <aimer@purejs.icu>
Date: Fri, 6 Feb 2026 18:00:09 +0800
Subject: [PATCH 08/15] fix(scheme/time): import s7-round as needed

---
 goldfish/scheme/time.scm | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/goldfish/scheme/time.scm b/goldfish/scheme/time.scm
index 8993c02e..bbdebf90 100644
--- a/goldfish/scheme/time.scm
+++ b/goldfish/scheme/time.scm
@@ -15,7 +15,7 @@
 ;
 
 (define-library (scheme time)
-  (import (only (scheme base) let-values))
+  (import (only (scheme base) let-values s7-round))
   (export current-second current-jiffy jiffies-per-second
           get-time-of-day monotonic-nanosecond
           system-clock-resolution steady-clock-resolution)
@@ -34,7 +34,7 @@
 
     (define (current-jiffy)
       ;; NOTE: use the s7-round to ensure that a natural number is returned.
-      (s7-round (* (current-second) (jiffies-per-second))))))
+      (s7-round (* (current-second) (jiffies-per-second))))
 
-     ; end of begin
-   ; end of define-library
+    ) ; end of begin
+  ) ; end of define-library

From 1ea7561a396d18667406dd4acb19efaf8a644331 Mon Sep 17 00:00:00 2001
From: Jinser Kafka <aimer@purejs.icu>
Date: Fri, 6 Feb 2026 18:02:00 +0800
Subject: [PATCH 09/15] fix(srfi-19): import open-io as needed

---
 goldfish/srfi/srfi-19.scm | 1 +
 1 file changed, 1 insertion(+)

diff --git a/goldfish/srfi/srfi-19.scm b/goldfish/srfi/srfi-19.scm
index e28cc2dc..714df300 100644
--- a/goldfish/srfi/srfi-19.scm
+++ b/goldfish/srfi/srfi-19.scm
@@ -51,6 +51,7 @@
                   (get-time-of-day      glue:get-time-of-day)
                   (monotonic-nanosecond glue:monotonic-nanosecond))
           (only (srfi srfi-13) string-pad string-tokenize string-trim-right)
+          (only (scheme base) open-output-string open-input-string get-output-string)
           (liii error))
   (export
     ;; Constants

From 03334f81bac9c4d49c08895d0b2b92a10ebf264e Mon Sep 17 00:00:00 2001
From: Jinser Kafka <aimer@purejs.icu>
Date: Fri, 6 Feb 2026 18:05:23 +0800
Subject: [PATCH 10/15] fix(srfi-19): ~l format (same issue as ~V)

---
 goldfish/srfi/srfi-19.scm | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/goldfish/srfi/srfi-19.scm b/goldfish/srfi/srfi-19.scm
index 714df300..6ac927f3 100644
--- a/goldfish/srfi/srfi-19.scm
+++ b/goldfish/srfi/srfi-19.scm
@@ -462,10 +462,10 @@
           ((#\k) (display (priv:padding (date-hour date)
                                         #\space 2)
                           port))
-          ((#\l) (let* ((hr  (date-hour date))
-                        (hr* (if (> hr 12) (- hr 12) hr)))
-                   (display (priv:padding hr* #\space 2)
-                            port)))
+          ((#\l) (display (priv:padding (+ 1 (modulo (- (date-hour date) 1) 12))
+                                        #\space
+                                        2)
+                          port))
           ((#\m) (display (priv:padding (date-month date)
                                         pad-with 2)
                           port))

From 6c7366063a5b61ea93c82600f635ad2d4c960863 Mon Sep 17 00:00:00 2001
From: Jinser Kafka <aimer@purejs.icu>
Date: Fri, 6 Feb 2026 18:40:20 +0800
Subject: [PATCH 11/15] fix(srfi-19) date-week-number-iso (used in ~V format)

---
 goldfish/srfi/srfi-19.scm | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/goldfish/srfi/srfi-19.scm b/goldfish/srfi/srfi-19.scm
index 6ac927f3..1256e6c4 100644
--- a/goldfish/srfi/srfi-19.scm
+++ b/goldfish/srfi/srfi-19.scm
@@ -389,18 +389,17 @@
 
     (define (priv:date-week-number-iso date)
       (let* ((year (date-year date))
-             (yday (date-year-day date))
              (jan1-wday (priv:week-day 1 1 year))
-             ;; 可能为0或53+
-             (raw-week (+ (quotient (+ yday jan1-wday -2) 7)
-                          (if (> jan1-wday 4) 0 1))))
+             (offset (if (> jan1-wday 4) 0 1))
+             ;; 调整值：补偿 1-based 和 周日归属
+             (adjusted (+ (date-year-day date) jan1-wday -2))
+             (raw-week (+ (floor-quotient adjusted 7) offset)))
+        (cond ((zero? raw-week)
+               (priv:date-week-number-iso 
+                (make-date 0 0 0 0 31 12 (- year 1) 0)))
 
-        (cond ((<= raw-week 0)
-               ;; 归前一年：判断前一年52周还是53周（周四年首=53周）
-               (if (> (priv:week-day 1 1 (- year 1)) 4) 52 53))
               ((and (= raw-week 53)
                     (<= (priv:week-day 1 1 (+ year 1)) 4))
-               ;; 归下一年第1周
                1)
 
               (else raw-week))))

From d87e89de6040f7b9ea0b50861648986ad8d4c554 Mon Sep 17 00:00:00 2001
From: Jinser Kafka <aimer@purejs.icu>
Date: Fri, 6 Feb 2026 18:43:35 +0800
Subject: [PATCH 12/15] fix(srfi-19): import receive as needed

---
 goldfish/srfi/srfi-19.scm | 1 +
 1 file changed, 1 insertion(+)

diff --git a/goldfish/srfi/srfi-19.scm b/goldfish/srfi/srfi-19.scm
index 1256e6c4..758ec177 100644
--- a/goldfish/srfi/srfi-19.scm
+++ b/goldfish/srfi/srfi-19.scm
@@ -51,6 +51,7 @@
                   (get-time-of-day      glue:get-time-of-day)
                   (monotonic-nanosecond glue:monotonic-nanosecond))
           (only (srfi srfi-13) string-pad string-tokenize string-trim-right)
+          (only (srfi srfi-8) receive)
           (only (scheme base) open-output-string open-input-string get-output-string)
           (liii error))
   (export

From bf2fd1c74f5f6c7acade63f866dc5c1c8881523b Mon Sep 17 00:00:00 2001
From: Jinser Kafka <aimer@purejs.icu>
Date: Fri, 6 Feb 2026 18:47:19 +0800
Subject: [PATCH 13/15] chore(srfi-19): comment on priv:padding

---
 goldfish/srfi/srfi-19.scm | 1 +
 1 file changed, 1 insertion(+)

diff --git a/goldfish/srfi/srfi-19.scm b/goldfish/srfi/srfi-19.scm
index 758ec177..9077f4e8 100644
--- a/goldfish/srfi/srfi-19.scm
+++ b/goldfish/srfi/srfi-19.scm
@@ -378,6 +378,7 @@
     (define (priv:locale-long-month n)
       (vector-ref priv:LOCALE-LONG-MONTH-VECTOR n))
 
+    ;; Only handles positive integers `n`. Internal use only.
     (define (priv:padding n pad-with len)
       (let* ((str     (number->string n))
              (str-len (string-length str)))

From 5b8a91559bd71a54d48bf3d2d6d61cc165036034 Mon Sep 17 00:00:00 2001
From: Jinser Kafka <aimer@purejs.icu>
Date: Fri, 6 Feb 2026 18:48:34 +0800
Subject: [PATCH 14/15] fix(srfi-19): import floor/ as needed

---
 goldfish/srfi/srfi-19.scm | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/goldfish/srfi/srfi-19.scm b/goldfish/srfi/srfi-19.scm
index 9077f4e8..8ccbe89e 100644
--- a/goldfish/srfi/srfi-19.scm
+++ b/goldfish/srfi/srfi-19.scm
@@ -52,7 +52,8 @@
                   (monotonic-nanosecond glue:monotonic-nanosecond))
           (only (srfi srfi-13) string-pad string-tokenize string-trim-right)
           (only (srfi srfi-8) receive)
-          (only (scheme base) open-output-string open-input-string get-output-string)
+          (only (scheme base) open-output-string open-input-string get-output-string
+                              floor/)
           (liii error))
   (export
     ;; Constants

From 0a87f21e1504acc9d6b529e2d6cae854f29c7fc5 Mon Sep 17 00:00:00 2001
From: jinser <aimer@purejs.icu>
Date: Fri, 6 Feb 2026 18:51:01 +0800
Subject: [PATCH 15/15] chore(goldfish/glue): add desc for
 `g_monotonic-nanosecond`

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 src/goldfish.hpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/goldfish.hpp b/src/goldfish.hpp
index cbc1c6f6..293ffec3 100644
--- a/src/goldfish.hpp
+++ b/src/goldfish.hpp
@@ -447,7 +447,7 @@ glue_scheme_time (s7_scheme* sc) {
              s7_make_typed_function (sc, s_get_time_of_day, f_get_time_of_day, 0, 0, false, d_get_time_of_day, NULL));
 
   const char* s_monotonic_nanosecond= "g_monotonic-nanosecond";
-  const char* d_monotonic_nanosecond= "(g_monotonic-nanosecond): () => integer, TODO";
+  const char* d_monotonic_nanosecond= "(g_monotonic-nanosecond): () => integer, returns the steady clock's monotonic nanoseconds since an unspecified epoch";
   s7_define (sc, cur_env, s7_make_symbol (sc, s_monotonic_nanosecond),
              s7_make_typed_function (sc, s_monotonic_nanosecond, f_monotonic_nanosecond, 0, 0, false, d_monotonic_nanosecond, NULL));