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Diffstat (limited to 'dev-haskell/chasingbottoms/metadata.xml')
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diff --git a/dev-haskell/chasingbottoms/metadata.xml b/dev-haskell/chasingbottoms/metadata.xml deleted file mode 100644 index 697509ead8f5..000000000000 --- a/dev-haskell/chasingbottoms/metadata.xml +++ /dev/null @@ -1,102 +0,0 @@ -<?xml version="1.0" encoding="UTF-8"?> -<!DOCTYPE pkgmetadata SYSTEM "https://www.gentoo.org/dtd/metadata.dtd"> -<pkgmetadata> - <maintainer type="project"> - <email>haskell@gentoo.org</email> - <name>Gentoo Haskell</name> - </maintainer> - <longdescription> - Do you ever feel the need to test code involving bottoms (e.g. calls to - the @error@ function), or code involving infinite values? Then this - library could be useful for you. - - It is usually easy to get a grip on bottoms by showing a value and - waiting to see how much gets printed before the first exception is - encountered. However, that quickly gets tiresome and is hard to automate - using e.g. QuickCheck - (<http://www.cse.chalmers.se/~rjmh/QuickCheck/>). With this library you - can do the tests as simply as the following examples show. - - Testing explicitly for bottoms: - - [@> isBottom (head [\])@] @True@ - - [@> isBottom bottom@] @True@ - - [@> isBottom (\\_ -> bottom)@] @False@ - - [@> isBottom (bottom, bottom)@] @False@ - - Comparing finite, partial values: - - [@> ((bottom, 3) :: (Bool, Int)) ==! (bottom, 2+5-4)@] @True@ - - [@> ((bottom, bottom) :: (Bool, Int)) <! (bottom, 8)@] @True@ - - Showing partial and infinite values (@\\\/!@ is join and @\/\\!@ is meet): - - [@> approxShow 4 $ (True, bottom) \\\/! (bottom, \'b\')@] @\"Just (True, \'b\')\"@ - - [@> approxShow 4 $ (True, bottom) \/\\! (bottom, \'b\')@] @\"(_|_, _|_)\"@ - - [@> approxShow 4 $ ([1..\] :: [Int\])@] @\"[1, 2, 3, _\"@ - - [@> approxShow 4 $ (cycle [bottom\] :: [Bool\])@] @\"[_|_, _|_, _|_, _\"@ - - Approximately comparing infinite, partial values: - - [@> approx 100 [2,4..\] ==! approx 100 (filter even [1..\] :: [Int\])@] @True@ - - [@> approx 100 [2,4..\] \/=! approx 100 (filter even [bottom..\] :: [Int\])@] @True@ - - The code above relies on the fact that @bottom@, just as @error - \"...\"@, @undefined@ and pattern match failures, yield - exceptions. Sometimes we are dealing with properly non-terminating - computations, such as the following example, and then it can be nice to - be able to apply a time-out: - - [@> timeOut' 1 (reverse [1..5\])@] @Value [5,4,3,2,1]@ - - [@> timeOut' 1 (reverse [1..\])@] @NonTermination@ - - The time-out functionality can be used to treat \"slow\" computations as - bottoms: - - [@> let tweak = Tweak &#x7b; approxDepth = Just 5, timeOutLimit = Just 2 &#x7d;@] - - [@> semanticEq tweak (reverse [1..\], [1..\]) (bottom :: [Int\], [1..\] :: [Int\])@] @True@ - - [@> let tweak = noTweak &#x7b; timeOutLimit = Just 2 &#x7d;@] - - [@> semanticJoin tweak (reverse [1..\], True) ([\] :: [Int\], bottom)@] @Just ([],True)@ - - This can of course be dangerous: - - [@> let tweak = noTweak &#x7b; timeOutLimit = Just 0 &#x7d;@] - - [@> semanticEq tweak (reverse [1..100000000\]) (bottom :: [Integer\])@] @True@ - - Timeouts can also be applied to @IO@ computations: - - [@> let primes = unfoldr (\\(x:xs) -> Just (x, filter ((\/= 0) . (\`mod\` x)) xs)) [2..\]@] - - [@> timeOutMicro 100 (print $ filter ((== 1) . (\`mod\` 83)) primes)@] @[167,499,9NonTermination@ - - [@> timeOutMicro 100 (print $ take 6 $ filter ((== 1) . (\`mod\` 83)) primes)@] @[167,499,997,1163,1993NonTermination@ - - [@> timeOutMicro 100 (print $ take 6 $ filter ((== 1) . (\`mod\` 83)) primes)@] @[167,499,997,1163,1993,2657]@ - - [@ @] @Value ()@ - - For the underlying theory and a larger example involving use of - QuickCheck, see the article \"Chasing Bottoms, A Case Study in Program - Verification in the Presence of Partial and Infinite Values\" - (<http://www.cse.chalmers.se/~nad/publications/danielsson-jansson-mpc2004.html>). - - The code has been tested using GHC. Most parts can probably be - ported to other Haskell compilers, but this would require some work. - The @TimeOut@ functions require preemptive scheduling, and most of - the rest requires @Data.Generics@; @isBottom@ only requires - exceptions, though. - </longdescription> -</pkgmetadata> |