/var/lib/ghc/package.conf.d/ChasingBottoms-1.3.0.13.conf is in libghc-chasingbottoms-dev 1.3.0.13-5.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 | name: ChasingBottoms
version: 1.3.0.13
id: ChasingBottoms-1.3.0.13-55ccbabf1327becf994c8aae54d8405c
key: Chasi_3a5VrLFXb8dGUdeWK8NANx
license: MIT
copyright: Copyright (c) Nils Anders Danielsson 2004-2015.
maintainer: http://www.cse.chalmers.se/~nad/
synopsis: For testing partial and infinite values.
description:
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 { approxDepth = Just 5, timeOutLimit = Just 2 }
> semanticEq tweak (reverse [1..], [1..]) (bottom :: [Int], [1..] :: [Int])
True
@
.
@
> let tweak = noTweak { timeOutLimit = Just 2 }
> semanticJoin tweak (reverse [1..], True) ([] :: [Int], bottom)
Just ([],True)
@
.
This can of course be dangerous:
.
@
> let tweak = noTweak { timeOutLimit = Just 0 }
> 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 $ primes ())
> [2,NonTermination
> > timeOutMicro 10000 (print $ take 10 $ primes ())
> [2,3,5,7,11,13,17,19,23,29]
> 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.
category: Testing
author: Nils Anders Danielsson
exposed: True
exposed-modules:
Test.ChasingBottoms Test.ChasingBottoms.Approx
Test.ChasingBottoms.ApproxShow
Test.ChasingBottoms.ContinuousFunctions
Test.ChasingBottoms.IsBottom Test.ChasingBottoms.Nat
Test.ChasingBottoms.SemanticOrd Test.ChasingBottoms.TimeOut
hidden-modules: Test.ChasingBottoms.IsType
trusted: False
import-dirs: /usr/lib/haskell-packages/ghc/lib/x86_64-linux-ghc-7.10.3/ChasingBottoms-1.3.0.13-3a5VrLFXb8dGUdeWK8NANx
library-dirs: /usr/lib/haskell-packages/ghc/lib/x86_64-linux-ghc-7.10.3/ChasingBottoms-1.3.0.13-3a5VrLFXb8dGUdeWK8NANx
data-dir: /usr/share/chasingbottoms
hs-libraries: HSChasingBottoms-1.3.0.13-3a5VrLFXb8dGUdeWK8NANx
depends:
QuickCheck-2.8.1-3b4e59fb7b4229f7e8519c5347611ffa
base-4.8.2.0-0d6d1084fbc041e1cded9228e80e264d
containers-0.5.6.2-59326c33e30ec8f6afd574cbac625bbb
mtl-2.2.1-3af90341e75ee52dfc4e3143b4e5d219
random-1.1-c46cc413d88c0a330b5495d03f0ed464
syb-0.6-d154b8ffa473f7cfcfc32ca4d99f62f7
haddock-interfaces: /usr/lib/ghc-doc/haddock/chasingbottoms-1.3.0.13/ChasingBottoms.haddock
haddock-html: /usr/share/doc/libghc-chasingbottoms-doc/html/
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