[Haskell-cafe] Lift data from IO to Validation

Debasish Ghosh ghosh.debasish at gmail.com
Sat Jan 4 14:58:50 UTC 2020

Hi -

I am not an experienced Haskell programmer and would like to have some help
with the following problem ..

I am trying to validate a bunch of inputs and found the package
Data.Validation. I am also using Data.Time for date and time. I have a
function like this ..

validateOpenDate :: ZonedTime -> Validation [String] ZonedTime

It's supposed to validate a date for which I need to fetch the current date
and time. I can do that with getZonedTime :: IO ZonedTime. I want to check
if the current time is less than the date time I pass to the function and
return an appropriate Validation.

The question is how do I lift the result from IO into the Validation ? Or
is there any alternative strategy that I should consider for this
validation ? I have a number of other validations which follow the same
strategy but don't have the IO. My final goal is to be able to compose all
these validations applicatively to prepare a final ADT in a smart

Any help will be appreciated ..


Debasish Ghosh
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