src/DateTester.lhs

   1 %  Copyright (C) 2008 Eric Kow
   2 %
   3 %  This program is free software; you can redistribute it and/or modify
   4 %  it under the terms of the GNU General Public License as published by
   5 %  the Free Software Foundation; either version 2, or (at your option)
   6 %  any later version.
   7 %
   8 %  This program is distributed in the hope that it will be useful,
   9 %  but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 %  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 %  GNU General Public License for more details.
  12 %
  13 %  You should have received a copy of the GNU General Public License
  14 %  along with this program; see the file COPYING.  If not, write to
  15 %  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  16 %  Boston, MA 02110-1301, USA.
  17
  18 To be loaded with GHCi
  19
  20 \begin{verbatim}
  21 make ghci
  22 Prelude>:l DateTester
  23 *DateTester>testDate   "2008/05/22 10:34"
  24 *DateTester>testDateAt "2006-03-22 09:36" "2008/05/22 10:34"
  25 \end{verbatim}
  26
  27 You could also just compile it if you want, but I don't see
  28 the point.
  29
  30 \begin{code}
  31 module DateTester where
  32
  33 import DateMatcher
  34 import IsoDate
  35 import System.Time
  36
  37 -- | 'testDate' @d@ shows the possible interpretations
  38 --   for the date string @d@ and how they match against
  39 --   the current date
  40 testDate :: String -> IO ()
  41 testDate d =
  42  do now <- getClockTime >>= toCalendarTime
  43     testDateAtCal now d
  44
  45 -- | 'testDate' @iso d@ shows the possible interpretations
  46 --   for the date string @d@ and how they match against
  47 --   the date represented by the ISO 8601 string @iso@
  48 testDateAt :: String -> String -> IO ()
  49 testDateAt iso d = testDateAtCal (readUTCDate iso) d
  50
  51 -- | helper function for 'testDate' and 'testDateAt'
  52 testDateAtCal :: CalendarTime -> String -> IO ()
  53 testDateAtCal c d =
  54  do ms <- getMatchers d
  55     putStr . unlines . map (showMatcher c) $ ms
  56
  57 -- | 'showMatcher' @c dm@ tells us if @dm@ applies to
  58 --   'CalendarTime' @c@; or if @dm@ just represents the
  59 --   failure to parse a date, in which case @c@ is moot.
  60 showMatcher :: CalendarTime -> DateMatcher -> String
  61 showMatcher now (DM n p m) =
  62    "==== " ++ n ++ " ====\n" ++
  63    (case p of
  64      Left err -> shows err ""
  65      Right x  -> show x ++ "\n" ++ (show $ m x now))
  66 \end{code}