[Haskell-beginners] iterating over a range of dates

[David McBride]

Sorry, I misunderstood your ruby.  The Day datatype has an ordinal
instance for this purpose and also a convenient show instance in case
you wanted it.

import Data.Time.Calendar
import Data.Time.Format
import System.Locale

main =
  let
    (Just now) = (parseTime defaultTimeLocale "%F" "2011-07-11" :: Maybe Day)
    (Just end) = (parseTime defaultTimeLocale "%F" "2011-07-15" :: Maybe Day)
  in mapM_ print [now..end]


On Sat, Jul 9, 2011 at 1:14 PM, David McBride <dmcbride at neondsl.com> wrote:
> import Data.Time.LocalTime
> import Data.Time.Format
> import System.Locale
>
> now :: Maybe LocalTime -- Change this to get different types of values
> (days, etc).
> now = parseTime defaultTimeLocale "%F" "2011-07-11"
>
> main = putStrLn $ case now of
>                    Nothing -> "Failed Parse"
>                    Just x -> (formatTime defaultTimeLocale "%F" x)
>
> On Sat, Jul 9, 2011 at 12:33 PM, Rolf Hanson <rolf.hanson at gmail.com> wrote:
>> Hi, I'm trying to iterate over a range of dates and print them out.
>> Here's how I am doing it in Ruby:
>>
>> 'require 'date'
>>
>> now      = Date.parse('2011-07-11')
>> end_date = Date.parse('2011-12-31')
>>
>> (now..end_date).each do |d|
>>  # print out a date that looks like:
>>  # Monday, July 11, 2011
>>  puts "#{d.strftime('%A, %B %d, %Y')}"
>> end
>>
>> I've been looking at the docs for Data.Time.Format and Data.Time.Calendar and am a bit puzzled at where to begin. Anyone have ideas? I've not found many (any?) examples of time and date manipulation in Haskell.
>>
>> RW
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>