hledger/hledger-lib/Hledger/Utils.hs
2015-08-24 16:24:11 -07:00

142 lines
4.5 KiB
Haskell

{-|
Standard imports and utilities which are useful everywhere, or needed low
in the module hierarchy. This is the bottom of hledger's module graph.
-}
module Hledger.Utils (---- provide these frequently used modules - or not, for clearer api:
-- module Control.Monad,
-- module Data.List,
-- module Data.Maybe,
-- module Data.Time.Calendar,
-- module Data.Time.Clock,
-- module Data.Time.LocalTime,
-- module Data.Tree,
-- module Text.RegexPR,
-- module Test.HUnit,
-- module Text.Printf,
---- all of this one:
module Hledger.Utils,
module Hledger.Utils.Debug,
module Hledger.Utils.Parse,
module Hledger.Utils.Regex,
module Hledger.Utils.String,
module Hledger.Utils.Test,
module Hledger.Utils.Tree,
-- Debug.Trace.trace,
-- module Data.PPrint,
-- module Hledger.Utils.UTF8IOCompat
SystemString,fromSystemString,toSystemString,error',userError',
-- the rest need to be done in each module I think
)
where
import Control.Monad (liftM)
import Control.Monad.IO.Class (MonadIO, liftIO)
-- import Data.Char
-- import Data.List
-- import Data.Maybe
-- import Data.PPrint
import Data.Time.Clock
import Data.Time.LocalTime
import System.Directory (getHomeDirectory)
import System.FilePath((</>), isRelative)
import System.IO
-- import Text.Printf
-- import qualified Data.Map as Map
import Hledger.Utils.Debug
import Hledger.Utils.Parse
import Hledger.Utils.Regex
import Hledger.Utils.String
import Hledger.Utils.Test
import Hledger.Utils.Tree
-- import Prelude hiding (readFile,writeFile,appendFile,getContents,putStr,putStrLn)
-- import Hledger.Utils.UTF8IOCompat (readFile,writeFile,appendFile,getContents,putStr,putStrLn)
import Hledger.Utils.UTF8IOCompat (SystemString,fromSystemString,toSystemString,error',userError')
-- tuples
first3 (x,_,_) = x
second3 (_,x,_) = x
third3 (_,_,x) = x
first4 (x,_,_,_) = x
second4 (_,x,_,_) = x
third4 (_,_,x,_) = x
fourth4 (_,_,_,x) = x
first5 (x,_,_,_,_) = x
second5 (_,x,_,_,_) = x
third5 (_,_,x,_,_) = x
fourth5 (_,_,_,x,_) = x
fifth5 (_,_,_,_,x) = x
first6 (x,_,_,_,_,_) = x
second6 (_,x,_,_,_,_) = x
third6 (_,_,x,_,_,_) = x
fourth6 (_,_,_,x,_,_) = x
fifth6 (_,_,_,_,x,_) = x
sixth6 (_,_,_,_,_,x) = x
-- lists
splitAtElement :: Eq a => a -> [a] -> [[a]]
splitAtElement x l =
case l of
[] -> []
e:es | e==x -> split es
es -> split es
where
split es = let (first,rest) = break (x==) es
in first : splitAtElement x rest
-- time
getCurrentLocalTime :: IO LocalTime
getCurrentLocalTime = do
t <- getCurrentTime
tz <- getCurrentTimeZone
return $ utcToLocalTime tz t
-- misc
isLeft :: Either a b -> Bool
isLeft (Left _) = True
isLeft _ = False
isRight :: Either a b -> Bool
isRight = not . isLeft
-- | Apply a function the specified number of times. Possibly uses O(n) stack ?
applyN :: Int -> (a -> a) -> a -> a
applyN n f = (!! n) . iterate f
-- | Convert a possibly relative, possibly tilde-containing file path to an absolute one,
-- given the current directory. ~username is not supported. Leave "-" unchanged.
expandPath :: MonadIO m => FilePath -> FilePath -> m FilePath -- general type sig for use in reader parsers
expandPath _ "-" = return "-"
expandPath curdir p = (if isRelative p then (curdir </>) else id) `liftM` expandPath' p
where
expandPath' ('~':'/':p) = liftIO $ (</> p) `fmap` getHomeDirectory
expandPath' ('~':'\\':p) = liftIO $ (</> p) `fmap` getHomeDirectory
expandPath' ('~':_) = error' "~USERNAME in paths is not supported"
expandPath' p = return p
firstJust ms = case dropWhile (==Nothing) ms of
[] -> Nothing
(md:_) -> md
-- | Read a file in universal newline mode, handling whatever newline convention it may contain.
readFile' :: FilePath -> IO String
readFile' name = do
h <- openFile name ReadMode
hSetNewlineMode h universalNewlineMode
hGetContents h
-- | Total version of maximum, for integral types, giving 0 for an empty list.
maximum' :: Integral a => [a] -> a
maximum' [] = 0
maximum' xs = maximum xs