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| author | taylorfausak <taylor@fausak.me> | 2019-10-03 22:24:55 -0400 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2019-11-01 04:54:47 -0400 |
| commit | dc4876421386b406dd43a6015f09d92c3e9fb7d8 (patch) | |
| tree | 42c30135affe34227c841cc77a6ec9c9de867aa5 | |
| parent | 73d6e508e6ce0b66bd082419effc0010b1dc9668 (diff) | |
| download | haskell-dc4876421386b406dd43a6015f09d92c3e9fb7d8.tar.gz | |
Implement `round` for `Ratio` that doesn't explode with `Natural`s
| -rw-r--r-- | libraries/base/GHC/Real.hs | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/libraries/base/GHC/Real.hs b/libraries/base/GHC/Real.hs index 10d8a54504..67ccf77596 100644 --- a/libraries/base/GHC/Real.hs +++ b/libraries/base/GHC/Real.hs @@ -508,6 +508,13 @@ instance (Integral a) => RealFrac (Ratio a) where {-# SPECIALIZE instance RealFrac Rational #-} properFraction (x:%y) = (fromInteger (toInteger q), r:%y) where (q,r) = quotRem x y + round r = + let (n, f) = properFraction r + in case (compare (abs f) 0.5, odd n) of + (LT, _) -> n + (EQ, False) -> n + (EQ, True) -> n + signum n + (GT, _) -> n + signum n -- | @since 2.0.1 instance (Show a) => Show (Ratio a) where |