comparison lib/ur/datetime.ur @ 1988:abb6981a2c4c

Merge with small clean-ups
author Adam Chlipala <adam@chlipala.net>
date Tue, 18 Feb 2014 07:07:01 -0500
parents 50322ba22972
children
comparison
equal deleted inserted replaced
1970:6bea98c7f736 1988:abb6981a2c4c
1 datatype day_of_week = Sunday | Monday | Tuesday | Wednesday | Thursday |
2 Friday | Saturday
3
4 val show_day_of_week = mkShow (fn dow => case dow of
5 Sunday => "Sunday"
6 | Monday => "Monday"
7 | Tuesday => "Tuesday"
8 | Wednesday => "Wednesday"
9 | Thursday => "Thursday"
10 | Friday => "Friday"
11 | Saturday => "Saturday")
12
13 fun dayOfWeekToInt dow = case dow of
14 Sunday => 0
15 | Monday => 1
16 | Tuesday => 2
17 | Wednesday => 3
18 | Thursday => 4
19 | Friday => 5
20 | Saturday => 6
21
22 fun intToDayOfWeek i = case i of
23 0 => Sunday
24 | 1 => Monday
25 | 2 => Tuesday
26 | 3 => Wednesday
27 | 4 => Thursday
28 | 5 => Friday
29 | 6 => Saturday
30 | n => error <xml>Invalid day of week {[n]}</xml>
31
32 val eq_day_of_week = mkEq (fn a b => dayOfWeekToInt a = dayOfWeekToInt b)
33
34
35 datatype month = January | February | March | April | May | June | July |
36 August | September | October | November | December
37
38 val show_month = mkShow (fn m => case m of
39 January => "January"
40 | February => "February"
41 | March => "March"
42 | April => "April"
43 | May => "May"
44 | June => "June"
45 | July => "July"
46 | August => "August"
47 | September => "September"
48 | October => "October"
49 | November => "November"
50 | December => "December")
51
52 type t = {
53 Year : int,
54 Month : month,
55 Day : int,
56 Hour : int,
57 Minute : int,
58 Second : int
59 }
60
61 fun monthToInt m = case m of
62 January => 0
63 | February => 1
64 | March => 2
65 | April => 3
66 | May => 4
67 | June => 5
68 | July => 6
69 | August => 7
70 | September => 8
71 | October => 9
72 | November => 10
73 | December => 11
74
75 fun intToMonth i = case i of
76 0 => January
77 | 1 => February
78 | 2 => March
79 | 3 => April
80 | 4 => May
81 | 5 => June
82 | 6 => July
83 | 7 => August
84 | 8 => September
85 | 9 => October
86 | 10 => November
87 | 11 => December
88 | n => error <xml>Invalid month number {[n]}</xml>
89
90 val eq_month = mkEq (fn a b => monthToInt a = monthToInt b)
91
92
93 fun toTime dt : time = fromDatetime dt.Year (monthToInt dt.Month) dt.Day
94 dt.Hour dt.Minute dt.Second
95
96 fun fromTime t : t = {
97 Year = datetimeYear t,
98 Month = intToMonth (datetimeMonth t),
99 Day = datetimeDay t,
100 Hour = datetimeHour t,
101 Minute = datetimeMinute t,
102 Second = datetimeSecond t
103 }
104
105 val ord_datetime = mkOrd { Lt = fn a b => toTime a < toTime b,
106 Le = fn a b => toTime a <= toTime b }
107
108 fun format fmt dt : string = timef fmt (toTime dt)
109
110 fun dayOfWeek dt : day_of_week = intToDayOfWeek (datetimeDayOfWeek (toTime dt))
111
112 val now : transaction t =
113 n <- now;
114 return (fromTime n)
115
116 (* Normalize a datetime. This will convert, e.g., January 32nd into February
117 1st. *)
118
119 fun normalize dt = fromTime (toTime dt)
120 fun addToField [nm :: Name] [rest ::: {Type}] [[nm] ~ rest]
121 (delta : int) (r : $([nm = int] ++ rest))
122 : $([nm = int] ++ rest) =
123 (r -- nm) ++ {nm = r.nm + delta}
124
125
126 (* Functions for adding to a datetime. There is no addMonths or addYears since
127 it's not clear what should be done; what's 1 month after January 31, or 1
128 year after February 29th?
129
130 These can't all be defined in terms of addSeconds because of leap seconds. *)
131
132 fun addSeconds n dt = normalize (addToField [#Second] n dt)
133 fun addMinutes n dt = normalize (addToField [#Minute] n dt)
134 fun addHours n dt = normalize (addToField [#Hour] n dt)
135 fun addDays n dt = normalize (addToField [#Day] n dt)