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| author | Daniel Rogozin <daniel.rogozin@serokell.io> | 2020-05-27 13:35:24 +0300 |
|---|---|---|
| committer | Vladislav Zavialov <vlad.z.4096@gmail.com> | 2021-02-05 20:29:46 +0300 |
| commit | 96029534f6386b4f64ae3a1f233897d96348a99d (patch) | |
| tree | 736d188b194ae5df23f1b619beec6a05b7c5aa49 /compiler/GHC/Data/FastString.hs | |
| parent | ddbdec4128f0e6760c8c7a19344f2f2a7a3314bf (diff) | |
| download | haskell-wip/ghc-11342-char-kind.tar.gz | |
The Char kind (#11342)wip/ghc-11342-char-kind
Co-authored-by: Rinat Stryungis <rinat.stryungis@serokell.io>
Implement GHC Proposal #387
* Parse char literals 'x' at the type level
* New built-in type families CmpChar, ConsSymbol, UnconsSymbol
* New KnownChar class (cf. KnownSymbol and KnownNat)
* New SomeChar type (cf. SomeSymbol and SomeNat)
* CharTyLit support in template-haskell
Updated submodules: binary, haddock.
Metric Decrease:
T5205
haddock.base
Metric Increase:
Naperian
T13035
Diffstat (limited to 'compiler/GHC/Data/FastString.hs')
| -rw-r--r-- | compiler/GHC/Data/FastString.hs | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/compiler/GHC/Data/FastString.hs b/compiler/GHC/Data/FastString.hs index 90d1c61594..d9363fe2e4 100644 --- a/compiler/GHC/Data/FastString.hs +++ b/compiler/GHC/Data/FastString.hs @@ -72,6 +72,7 @@ module GHC.Data.FastString -- ** Deconstruction unpackFS, -- :: FastString -> String + unconsFS, -- :: FastString -> Maybe (Char, FastString) -- ** Encoding zEncodeFS, @@ -608,6 +609,12 @@ headFS fs = head $ unpackFS fs consFS :: Char -> FastString -> FastString consFS c fs = mkFastString (c : unpackFS fs) +unconsFS :: FastString -> Maybe (Char, FastString) +unconsFS fs = + case unpackFS fs of + [] -> Nothing + (chr : str) -> Just (chr, mkFastString str) + uniqueOfFS :: FastString -> Int uniqueOfFS fs = uniq fs |