From 7e592e1d6ed5e0b25b37215da7558c6324688d6f Mon Sep 17 00:00:00 2001 From: Joey Hess Date: Fri, 22 Nov 2013 11:16:03 -0400 Subject: git-repair (1.20131122) unstable; urgency=low * Added test mode, which can be used to randomly corrupt test repositories, in reproducible ways, which allows easy corruption-driven-development. * Improve repair code in the case where the index file is corrupt, and this hides other problems. * Write a dummy .git/HEAD if the file is missing or corrupt, as git otherwise will not treat the repository as a git repo. * Improve fsck code to find badly corrupted objects that crash git fsck before it can complain about them. * Fixed crashes on bad file encodings. * Can now run 10000 tests (git-repair --test -n 10000 --force) with 0 failures. # imported from the archive --- Utility/PartialPrelude.hs | 68 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 Utility/PartialPrelude.hs (limited to 'Utility/PartialPrelude.hs') diff --git a/Utility/PartialPrelude.hs b/Utility/PartialPrelude.hs new file mode 100644 index 0000000..6efa093 --- /dev/null +++ b/Utility/PartialPrelude.hs @@ -0,0 +1,68 @@ +{- 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] -- cgit v1.2.3