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| author | John MacFarlane <jgm@berkeley.edu> | 2018-08-10 15:44:20 -0700 |
|---|---|---|
| committer | John MacFarlane <jgm@berkeley.edu> | 2018-08-10 15:44:20 -0700 |
| commit | 6003c596d7b348b29dd4f452f504bfd717634fa2 (patch) | |
| tree | eb5b396603e32b29bd8744ed8b310ad46704dea7 /src/Text/Pandoc/UUID.hs | |
| parent | 84e0b905196fae9924c847741c271f40ed57c83f (diff) | |
| download | pandoc-6003c596d7b348b29dd4f452f504bfd717634fa2.tar.gz | |
Avoid non-exhaustive pattern match.
Diffstat (limited to 'src/Text/Pandoc/UUID.hs')
| -rw-r--r-- | src/Text/Pandoc/UUID.hs | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/src/Text/Pandoc/UUID.hs b/src/Text/Pandoc/UUID.hs index c1bae7038..60ff269da 100644 --- a/src/Text/Pandoc/UUID.hs +++ b/src/Text/Pandoc/UUID.hs @@ -67,13 +67,14 @@ instance Show UUID where getUUID :: RandomGen g => g -> UUID getUUID gen = - let [a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p] = take 16 $ randoms gen :: [Word8] - -- set variant - i' = i `setBit` 7 `clearBit` 6 - -- set version (0100 for random) - g' = g `clearBit` 7 `setBit` 6 `clearBit` 5 `clearBit` 4 - in - UUID a b c d e f g' h i' j k l m n o p + case take 16 (randoms gen :: [Word8]) of + [a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p] -> + -- set variant + let i' = i `setBit` 7 `clearBit` 6 + -- set version (0100 for random) + g' = g `clearBit` 7 `setBit` 6 `clearBit` 5 `clearBit` 4 + in UUID a b c d e f g' h i' j k l m n o p + _ -> error "not enough random numbers for UUID" -- should not happen getRandomUUID :: IO UUID getRandomUUID = getUUID <$> getStdGen |