Changing the default timezone in Duckling about duckling

[stopachka]

Hey @nsanthanam

You can provide the reference time in the context, when calling parse.

Here's an example:

module Duckling.TimezoneExample
  ( parseText ) where

import Data.Text (Text)

import Duckling.Core
import Duckling.Data.TimeZone

parseText :: Text -> Text -> Lang -> IO [Entity]
parseText text tz lang = do
  tzs <- loadTimeZoneSeries "/usr/share/zoneinfo/"
  refTime <- currentReftime tzs tz
  let
    context = Context
      { referenceTime = refTime
      , lang = lang
      }
  return $ parse text context [This Time]

Now if we did parseText "in 2 minutes" "UTC" EN

You will get

[Entity {dim = "time", body = "in 2 minutes", value = Object (fromList [("values",Array [Object (fromList [("value",String "2017-09-01T19:51:15.246+00:00"),("grain",String "second"),("type",String "value")])]),("value",String "2017-09-01T19:51:15.246+00:00"),("grain",String "second"),("type",String "value")]), start = 0, end = 12}]

[nsanthanam]

Excellent thanks for the feedback, I was wondering why the code didn't work. From what you're saying, I can do something like:

parseText :: Text -> Text -> Locale -> IO [Entity]
parseText text tz locale = do
  tzs <- loadTimeZoneSeries "/usr/share/zoneinfo/"
  refTime <- currentReftime tzs tz
  let
    context = Context
      { referenceTime = refTime
      , locale = locale
      }
  return $ parse text context [This Time]

Here I'm assuming that locale is of type Locale rather than constructing Locale from lang and region. Is this correct?

How would I have to change my input to reflect this?

Thanks so much for all the help so far, really appreciate it.

[nsanthanam]

HI @stopachka, I compiled the code that you provided using :l parseText.hs (where parseText.hs is the filename, stored in the Duckling directory) in the stack repl (loaded with stack repl --no-load) and I see the following error:

[316 of 319] Compiling Duckling.Rules   ( /Users/navaneethan/Documents/freshML/duckling/Duckling/Rules.hs, interpreted )
[317 of 319] Compiling Duckling.Api     ( /Users/navaneethan/Documents/freshML/duckling/Duckling/Api.hs, interpreted )
[318 of 319] Compiling Duckling.Core    ( /Users/navaneethan/Documents/freshML/duckling/Duckling/Core.hs, interpreted )
[319 of 319] Compiling Duckling.TimezoneExample ( parseText.hs, interpreted )
parseText.hs:16:9: error: Not in scope: ‘lang’
Failed, modules loaded: Duckling.AmountOfMoney.BG.Rules, ...
...
...

It appears that the line , lang = lang (line 16) is causing the problem, but I don't understand Haskell well at all, so I'm not sure.

Could you help understand what the issue is?

Steps followed:
MacBook-Pro-4:Duckling navaneethan$ stack repl --no-load
Prelude> :l parseText.hs

[nsanthanam]

Hi @stopachka, I think I've managed to figure out the issue and wanted to see if this was the right way to fix it.

module Duckling.TimezoneExample
  ( parseText ) where

import Data.Text (Text)


import Duckling.Core
import Duckling.Data.TimeZone
import Duckling.Locale

parseText :: Text -> Text -> Lang -> Maybe Region -> IO [Entity]
parseText text tz lang region = do
  tzs <- loadTimeZoneSeries "/usr/share/zoneinfo/"
  refTime <- currentReftime tzs tz
  let
    context = Context
      { referenceTime = refTime
      , locale = Locale lang (region)
      }
  return $ parse text context [This Time]

I made two changes

1. Line 11: I changed parseText :: Text -> Text -> Lang -> IO [Entity] to parseText :: Text -> Text -> Lang -> Maybe Region -> IO [Entity].
2. Line 18: I changed , lang = lang to , locale = Locale lang (region)

The reason (I think) this works is because Context consists of a referenceTime and a locale, not a lang. And locale is composed of a lang and region. I don't yet understand how Maybe works, though.

Now the code compiles and when I present it with timezones of the format Asia/Tbilisi or America/Chicago, it parses the string and returns the time relative to that timezone.

Could you tell me if this is the correct way of doing things? Also, I'm guessing I can expose parseText as an API endpoint, but wanted to check.

[patapizza]

Hi @nsanthanam, since then we've implemented locales (this is why @stopachka's example isn't working anymore). What you did works, though I would suggest to have parseText directly accepts a Locale. For an example on how to wrap this into a server, you can look into exe/ExampleMain.hs.

[patapizza]

That's correct, you'd have to move the locale construction from the function to the callsite.

[ydshieh]

Hi @nsanthanam, since then we've implemented locales (this is why @stopachka's example isn't working anymore). What you did works, though I would suggest to have parseText directly accepts a Locale. For an example on how to wrap this into a server, you can look into exe/ExampleMain.hs.

@stopachka, Do you know if the server duckling-example-exe in exe/ExampleMain.hs already support specifying timezone and how? I can't find information I can use.

[patapizza]

@chiapas Yes, through the tz parameter.