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README
¶
ptime
Parse date and times without knowing the layout ahead of time.
Experimental and a work in progress. Use at your own risk.
Overview
This library is for parsing, on a best effort basis, input that is provided by a user without having to be strict on the layout. The goal is to accept commonly used layouts and try to reject those that don't make sense. Uncommon layouts may parse, may fail, or may parse incorrectly. The expectation is that the user is able to review the input and re-enter the date or time if it wasn't parsed correctly. This library is not appropriate for parsing in bulk with no supervision or when there needs to be a 100% guarantee that the parsing is correct.
Locales
A locale is necessary for parsing. The only locales pre-configured at the moment are en-US and fr-FR. The CLDR may be included at some point. In the mean time, structures can be constructed manually with the needed locale information.
Create a ptime.P structure with a locale:
p := ptime.For(locale.EnUS)
parsed, err := p.Parse("2006-01-02")
or call each function with a locale:
parsed, err := ptime.Parse(locale.EnUS, "2006-01-02")
Parsing
The result of a parse is a Parsed structure of strings that contains the
fields that were identified. For example:
ptime.Parse(locale.EnUS, "3:05pm")
returns this structure:
{
"Hour": "3",
"Minute": "05",
"Period": "PM",
"TimeSep": ":"
}
Names are normalized to an abbreviated format. For example:
ptime.Parse(locale.EnUS, "Friday, April 15 2014")
results this:
{
"Weekday": "Fri",
"Year": "2014",
"Month": "Apr",
"Day": "15",
"DateSep": " "
}
and:
ptime.Parse(locale.FrFR, "vendredi, 15 avril 2014")
returns this:
{
"Weekday": "ven.",
"Year": "2014",
"Month": "avr.",
"Day": "15",
"DateSep": " "
}
Besides Parse, there are ParseDate and ParseTime functions that can
be used to restrict the parse as needed.
Layouts known to work can be found by reviewing the test cases here:
https://github.com/blackchip-org/ptime/blob/main/parser_test.go
The results of parsing any other layout are undefined.
Time
A time.Time can be created from a Parsed structure given a reference
time. For example:
parsed, err := p.Parse("3:04:05pm MST")
if err != nil {
log.Panic(err)
}
t, err := ptime.Time(parsed, time.Now())
In this case, we don't want the time.Time value to be in the year 0, so the
year, month, and day is used from the reference time given as time.Now().
Use time.Time{} if you really want year 0 but be aware that times can
be weird there.
If a parsed value contains a 2 digit year, the century will be set to the year found in the reference time. If now is the year 2023 and the 2 digit year is 99, the year will evaluate to 2099. To get 1999, set the reference year to 1900 or use an explicit 4 digit year.
Formatting
Use the Format function to format a time.Time with an alterative syntax to
the one provided in the standard library. The function takes a layout and the
time to format. The contents of the layout are copied as-is and date/time
fields denoted in square brackets are evaluated. For example, the following
date:
2006-01-02
Can be formatted with:
[year]-[momth]-[day]
Field names can be followed by a / and a formatting directive. For example,
the following date:
2 Jan 06
Can be formatted with:
[day] [month/abbr] [year/2]
The available fields and formats are as follows:
| Field/Format | Example |
|---|---|
weekday |
"Monday" |
weekday/abbr |
"Mon" |
weekday/wide |
"Monday" |
year |
"2006" |
year/2 |
"06" |
month |
"1" |
month/2 |
" 1" |
month/02 |
"01" |
month/abbr |
"Jan" |
month/name |
"January" |
month/wide |
"January" |
day |
"2" |
day/2 |
" 2" |
day/02 |
"02" |
day/year |
"002" |
hour |
"15" |
hour/12 |
"3" |
hour/24 |
"15" |
minute |
"04" |
second |
"05" |
second/4 |
"05.9999" |
period |
"AM" |
period/abbr |
"AM" |
period/alt |
"am" |
period/abbr-alt |
"am" |
period/narrow |
"a" |
zone |
"MST" |
offset |
"-0700" |
offset/: |
"-07:00" |
offset-zone |
"-0700 MST" or "UTC" |
offset-zone/: |
"-07:00 MST" or "UTC" |
zone-offset |
"MST -0700" or "UTC" |
zone-offset/: |
"MST -07:00" or "UTC" |
Installation
Install go.
Install with:
go install github.com/blackchip-org/ptime/cmd/ptime@latest
Command line
A command line interface is provided for quick parsing and formatting.
Usage: ptime [options] field ...
-d only parse date
-f layout
format the result with layout
-l locale
set locale (default "en-US")
-t only parse time
-v verbose
Example:
ptime -l en-US Mon Jan 2 2006 3:04:05pm MST
Output:
{
"Weekday": "Mon",
"Year": "2006",
"Month": "Jan",
"Day": "2",
"Hour": "3",
"Minute": "04",
"Second": "05",
"Period": "PM",
"Zone": "MST",
"Offset": "-0700",
"DateSep": " ",
"TimeSep": ":"
}
Example:
ptime -l fr-FR lundi, 2/1/06 15:04:05,9999
Output:
{
"Weekday": "lun.",
"Year": "06",
"Month": "1",
"Day": "2",
"Hour": "15",
"Minute": "04",
"Second": "05",
"FracSecond": "9999",
"DateSep": "/",
"TimeSep": ":"
}
Example:
ptime -f "[day] [month/abbr] [year/2]" 2006-01-02
Output:
2 Jan 06
Code Example
package main
import (
"fmt"
"log"
"time"
"github.com/blackchip-org/ptime"
"github.com/blackchip-org/ptime/locale"
)
func main() {
p := ptime.ForLocale(locale.EnUS)
parsed, err := p.Parse("3:04:05pm MST")
if err != nil {
log.Panic(err)
}
t, err := p.Time(parsed, time.Now())
if err != nil {
log.Panic(err)
}
f := p.Format("[hour]:[minute]:[second] [offset]", t)
fmt.Println(f)
}
Output:
15:04:05 -0700
Also found here:
https://github.com/blackchip-org/ptime/blob/main/cmd/ptime-example/main.go
License
MIT
Feedback
Contact me at zc@blackchip.org
Documentation
¶
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func FormatOffset ¶
Types ¶
type Parsed ¶
type Parsed struct {
Weekday string `json:",omitempty"`
Year string `json:",omitempty"`
Month string `json:",omitempty"`
Day string `json:",omitempty"`
Hour string `json:",omitempty"`
Minute string `json:",omitempty"`
Second string `json:",omitempty"`
FracSecond string `json:",omitempty"`
Period string `json:",omitempty"`
Zone string `json:",omitempty"`
Offset string `json:",omitempty"`
DateSep string `json:",omitempty"`
TimeSep string `json:",omitempty"`
DateTimeSep string `json:",omitempty"`
HourSep string `json:",omitempty"`
}
Source Files
Directories