Re: [Haskell-cafe] Help parsing dates and times
dons's blog entry on parsing dates might point somewhere useful http://cgi.cse.unsw.edu.au/~dons/blog/2006/11/12#rpn-reloaded t. Don Stewart [EMAIL PROTECTED] Sent by: [EMAIL PROTECTED] 10/15/2007 08:25 PM To Justin Bailey [EMAIL PROTECTED] cc Haskell-Cafe haskell-cafe@haskell.org Subject Re: [Haskell-cafe] Help parsing dates and times jgbailey: I am trying to parse various date and time formats using the parseTime function found in (GHC 6.6.1) Data.Time.Format. The one that is giving me trouble looks like this: 2008-06-26T11:00:00.000-07:00 Specifically, the time zone offset isn't covered by the format parameters given. I can almost parse it with this: %FT%X.000 But that doesn't take into account the -07:00 bit. I'm sure this has been solved - can someone point me to the solution? Thanks in advance. Is there anything in the parsedate library? http://hackage.haskell.org/cgi-bin/hackage-scripts/package/parsedate-2006.11.10 http://hackage.haskell.org/packages/archive/parsedate/2006.11.10/doc/html/System-Time-Parse.html -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe --- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Help parsing dates and times
On Oct 16, 2007, at 2:25 , Don Stewart wrote: jgbailey: I am trying to parse various date and time formats using the parseTime function found in (GHC 6.6.1) Data.Time.Format. The one that is giving me trouble looks like this: 2008-06-26T11:00:00.000-07:00 Specifically, the time zone offset isn't covered by the format parameters given. I can almost parse it with this: %FT%X.000 But that doesn't take into account the -07:00 bit. I'm sure this has been solved - can someone point me to the solution? Thanks in advance. Try %z (see http://www.haskell.org/ghc/docs/latest/html/libraries/time/Data- Time-Format.html#v%3AformatTime for all the format specifiers). Is there anything in the parsedate library? http://hackage.haskell.org/cgi-bin/hackage-scripts/package/ parsedate-2006.11.10 http://hackage.haskell.org/packages/archive/parsedate/ 2006.11.10/doc/html/System-Time-Parse.html -- Don parsedate is obsolete, unless you have ghc 6.6.1. It was rewritten to become what is now the date parsing code in the time package. /Björn ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Help parsing dates and times
On 10/16/07, Bjorn Bringert [EMAIL PROTECTED] wrote:
Hmm, perhaps I should clarify this: parsedate and time-1.1.1 (which
comes with GHC 6.6.1) have different APIs. parsedate produces
CalendarTimes, and the code in time-1.1.1 produces the new time and
date data types. So I guess parsedate isn't actually obsolete,
rather, it's for use with the package currently known as 'old-time'.
Given this date string:
2008-06-26T11:00:00.000-07:00
The problem is the parseTime function in Data.Time.Format is a little too
strict. The following GHCi session shows the different behaviors. Notice how
%Z is unable to parse the time zone offset in any case. First we try
parseTime:
:m + Data.Time System.Time.Parse System.Locale
let dateStr = 2008-06-26T11:00:00.000-07:00
parseTime defaultTimeLocale %FT%X.000%z dateStr :: Maybe UTCTime
Nothing
parseTime defaultTimeLocale %FT%X.000-%z dateStr :: Maybe UTCTime
Nothing
parseTime defaultTimeLocale %FT%X.000 dateStr :: Maybe UTCTime
Nothing
Now parseCalendarTime from the parseDate package:
parseCalendarTime defaultTimeLocale %Y-%m-%dT%H:%M:%S dateStr
Just (CalendarTime {ctYear = 2008, ctMonth = June, ctDay = 26, ctHour =
11, ctMin = 0, ctSec = 0, ctPicosec = 0, ctWDay
= Thursday, ctYDay = 1, ctTZName = UTC, ctTZ = 0, ctIsDST = False})
parseCalendarTime defaultTimeLocale %Y-%m-%dT%H:%M:%S.000%Z dateStr
Nothing
Justin
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Re: [Haskell-cafe] Help parsing dates and times
On Oct 16, 2007, at 17:54 , Justin Bailey wrote:
On 10/16/07, Bjorn Bringert [EMAIL PROTECTED] wrote:
Hmm, perhaps I should clarify this: parsedate and time-1.1.1 (which
comes with GHC 6.6.1) have different APIs. parsedate produces
CalendarTimes, and the code in time-1.1.1 produces the new time and
date data types. So I guess parsedate isn't actually obsolete,
rather, it's for use with the package currently known as 'old-time'.
Given this date string:
2008-06-26T11:00:00.000-07:00
The problem is the parseTime function in Data.Time.Format is a
little too strict. The following GHCi session shows the different
behaviors. Notice how %Z is unable to parse the time zone offset in
any case. First we try parseTime:
:m + Data.Time System.Time.Parse System.Locale
let dateStr = 2008-06-26T11:00:00.000-07:00
parseTime defaultTimeLocale %FT%X.000%z dateStr :: Maybe UTCTime
Nothing
parseTime defaultTimeLocale %FT%X.000-%z dateStr :: Maybe
UTCTime
Nothing
parseTime defaultTimeLocale %FT%X.000 dateStr :: Maybe UTCTime
Nothing
I guess you really want a ZonedTime here, if you want to retain the
time zone info.
It seems like %z and %Z require 4 digits for a time zone offset,
without a colon. This works:
parseTime defaultTimeLocale %FT%X.000%z
2008-06-26T11:00:00.000-0700 :: Maybe ZonedTime
Just 2008-06-26 11:00:00 -0700
Should we just add XX:XX as an alternative time zone offset format
accepted by %z and %Z? Is this a standard format?
Now parseCalendarTime from the parseDate package:
parseCalendarTime defaultTimeLocale %Y-%m-%dT%H:%M:%S dateStr
Just (CalendarTime {ctYear = 2008, ctMonth = June, ctDay = 26,
ctHour = 11, ctMin = 0, ctSec = 0, ctPicosec = 0, ctWDay
= Thursday, ctYDay = 1, ctTZName = UTC, ctTZ = 0, ctIsDST = False})
parseCalendarTime defaultTimeLocale %Y-%m-%dT%H:%M:%S.000%Z
dateStr
Nothing
Hmm, ok, parsedate allows garbage at the end. I wonder what is the
right thing to do here.
/Björn
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Re: [Haskell-cafe] Help parsing dates and times
On 10/16/07, Bjorn Bringert [EMAIL PROTECTED] wrote: Should we just add XX:XX as an alternative time zone offset format accepted by %z and %Z? Is this a standard format? I'm not sure, but I am getting this date from Google in their XML feeds representing calendar data. The specific element is gd:when, documented here: http://code.google.com/apis/gdata/elements.html#gdWhen Hmm, ok, parsedate allows garbage at the end. I wonder what is the right thing to do here. A wildcard that allowed me to say don't care would work. If parseDate was built on regular expressions, then you could do whatever you wanted. I'm not familiar with the C roots of this function, though, so maybe it's best to do whatever it does. Regardless, I'm glad to have something. I can always filter/chop the string to remove the bits I don't care about. It's a good library. Justin ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Help parsing dates and times
On Tue, 2007-10-16 at 09:25 -0700, Justin Bailey wrote: On 10/16/07, Bjorn Bringert [EMAIL PROTECTED] wrote: Should we just add XX:XX as an alternative time zone offset format accepted by %z and %Z? Is this a standard format? Yes, this is standard; see below. I'm not sure, but I am getting this date from Google in their XML feeds representing calendar data. The specific element is gd:when, documented here: http://code.google.com/apis/gdata/elements.html#gdWhen That refers to XML Schema; the dateTime type in XML Schema is standardized here: http://www.w3.org/TR/xmlschema-2/#dateTime (and time zone offsets are required to have a colon in this format). Carl Witty ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Help parsing dates and times
On Oct 16, 2007, at 21:39 , Carl Witty wrote: On Tue, 2007-10-16 at 09:25 -0700, Justin Bailey wrote: On 10/16/07, Bjorn Bringert [EMAIL PROTECTED] wrote: Should we just add XX:XX as an alternative time zone offset format accepted by %z and %Z? Is this a standard format? Yes, this is standard; see below. I'm not sure, but I am getting this date from Google in their XML feeds representing calendar data. The specific element is gd:when, documented here: http://code.google.com/apis/gdata/elements.html#gdWhen That refers to XML Schema; the dateTime type in XML Schema is standardized here: http://www.w3.org/TR/xmlschema-2/#dateTime (and time zone offsets are required to have a colon in this format). Thanks, I have added this to the parser now. I can't push right now because of performance problems, but it'll be in darcs soon. Now it works: Prelude Data.Time System.Locale parseTime defaultTimeLocale %FT%T%Q% z 2008-06-26T11:00:00.087-07:00 :: Maybe ZonedTime Just 2008-06-26 11:00:00.087 -0700 Note that I use %Q for the second decimals instead of .000, this makes it accept non-integer seconds. /Björn ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Help parsing dates and times
I am trying to parse various date and time formats using the parseTime function found in (GHC 6.6.1) Data.Time.Format. The one that is giving me trouble looks like this: 2008-06-26T11:00:00.000-07:00 Specifically, the time zone offset isn't covered by the format parameters given. I can almost parse it with this: %FT%X.000 But that doesn't take into account the -07:00 bit. I'm sure this has been solved - can someone point me to the solution? Thanks in advance. Justin ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Help parsing dates and times
jgbailey: I am trying to parse various date and time formats using the parseTime function found in (GHC 6.6.1) Data.Time.Format. The one that is giving me trouble looks like this: 2008-06-26T11:00:00.000-07:00 Specifically, the time zone offset isn't covered by the format parameters given. I can almost parse it with this: %FT%X.000 But that doesn't take into account the -07:00 bit. I'm sure this has been solved - can someone point me to the solution? Thanks in advance. Is there anything in the parsedate library? http://hackage.haskell.org/cgi-bin/hackage-scripts/package/parsedate-2006.11.10 http://hackage.haskell.org/packages/archive/parsedate/2006.11.10/doc/html/System-Time-Parse.html -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
