git-annex/Utility/PartialPrelude.hs
Joey Hess e213ef310f git-annex (5.20140717) unstable; urgency=high
* Fix minor FD leak in journal code. Closes: #754608
  * direct: Fix handling of case where a work tree subdirectory cannot
    be written to due to permissions.
  * migrate: Avoid re-checksumming when migrating from hashE to hash backend.
  * uninit: Avoid failing final removal in some direct mode repositories
    due to file modes.
  * S3: Deal with AWS ACL configurations that do not allow creating or
    checking the location of a bucket, but only reading and writing content to
    it.
  * resolvemerge: New plumbing command that runs the automatic merge conflict
    resolver.
  * Deal with change in git 2.0 that made indirect mode merge conflict
    resolution leave behind old files.
  * sync: Fix git sync with local git remotes even when they don't have an
    annex.uuid set. (The assistant already did so.)
  * Set gcrypt-publish-participants when setting up a gcrypt repository,
    to avoid unncessary passphrase prompts.
    This is a security/usability tradeoff. To avoid exposing the gpg key
    ids who can decrypt the repository, users can unset
    gcrypt-publish-participants.
  * Install nautilus hooks even when ~/.local/share/nautilus/ does not yet
    exist, since it is not automatically created for Gnome 3 users.
  * Windows: Move .vbs files out of git\bin, to avoid that being in the
    PATH, which caused some weird breakage. (Thanks, divB)
  * Windows: Fix locking issue that prevented the webapp starting
    (since 5.20140707).

# imported from the archive
2014-07-17 11:27:25 -04:00

68 lines
1.6 KiB
Haskell

{- Parts of the Prelude are partial functions, which are a common source of
- bugs.
-
- This exports functions that conflict with the prelude, which avoids
- them being accidentially used.
-}
module Utility.PartialPrelude where
import qualified Data.Maybe
{- read should be avoided, as it throws an error
- Instead, use: readish -}
read :: Read a => String -> a
read = Prelude.read
{- head is a partial function; head [] is an error
- Instead, use: take 1 or headMaybe -}
head :: [a] -> a
head = Prelude.head
{- tail is also partial
- Instead, use: drop 1 -}
tail :: [a] -> [a]
tail = Prelude.tail
{- init too
- Instead, use: beginning -}
init :: [a] -> [a]
init = Prelude.init
{- last too
- Instead, use: end or lastMaybe -}
last :: [a] -> a
last = Prelude.last
{- Attempts to read a value from a String.
-
- Ignores leading/trailing whitespace, and throws away any trailing
- text after the part that can be read.
-
- readMaybe is available in Text.Read in new versions of GHC,
- but that one requires the entire string to be consumed.
-}
readish :: Read a => String -> Maybe a
readish s = case reads s of
((x,_):_) -> Just x
_ -> Nothing
{- Like head but Nothing on empty list. -}
headMaybe :: [a] -> Maybe a
headMaybe = Data.Maybe.listToMaybe
{- Like last but Nothing on empty list. -}
lastMaybe :: [a] -> Maybe a
lastMaybe [] = Nothing
lastMaybe v = Just $ Prelude.last v
{- All but the last element of a list.
- (Like init, but no error on an empty list.) -}
beginning :: [a] -> [a]
beginning [] = []
beginning l = Prelude.init l
{- Like last, but no error on an empty list. -}
end :: [a] -> [a]
end [] = []
end l = [Prelude.last l]