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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 |