Difference between revisions of "UTF-8"
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(whoops, reuse the same example, why don't we) |
(question - what about other string encodings?) |
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| (2 intermediate revisions by one other user not shown) | |||
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provides a drop-in replacement for System.IO |
provides a drop-in replacement for System.IO |
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| + | ''What about other string encodings?'' |
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| ⚫ | |||
| ⚫ | |||
| − | This example reverses every line in a file (saving the results in the file + ".rev") |
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| ⚫ | |||
| − | |||
| ⚫ | |||
<haskell> |
<haskell> |
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> import System.IO.UTF8 |
> import System.IO.UTF8 |
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| − | > import Prelude hiding (readFile) |
+ | > import Prelude hiding (readFile, writeFile) |
| + | > import System.Environment (getArgs) |
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</haskell> |
</haskell> |
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| + | |||
| + | The readFile and writeFile functions are the same as before... |
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<haskell> |
<haskell> |
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| Line 20: | Line 22: | ||
> do args <- getArgs |
> do args <- getArgs |
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> mapM_ reverseUTF8File args |
> mapM_ reverseUTF8File args |
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| + | |||
| − | |||
> reverseUTF8File :: FilePath -> IO () |
> reverseUTF8File :: FilePath -> IO () |
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> reverseUTF8File f = |
> reverseUTF8File f = |
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| − | > do |
+ | > do c <- readFile f |
| − | > writeFile (f ++ ".rev) $ reverseLines |
+ | > writeFile (f ++ ".rev") $ reverseLines c |
> where |
> where |
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> reverseLines = unlines . map reverse . lines |
> reverseLines = unlines . map reverse . lines |
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| − | + | </haskell> |
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Revision as of 02:22, 22 July 2008
The simplest solution seems to be to use the utf8-string package from Galois. It
provides a drop-in replacement for System.IO
What about other string encodings?
Example
If we use a function from System.IO.UTF8, we should also hide the equivalent one from the Prelude. (Alternatively, we could import the UTF8 module qualified)
> import System.IO.UTF8
> import Prelude hiding (readFile, writeFile)
> import System.Environment (getArgs)
The readFile and writeFile functions are the same as before...
> main :: IO ()
> main =
> do args <- getArgs
> mapM_ reverseUTF8File args
> reverseUTF8File :: FilePath -> IO ()
> reverseUTF8File f =
> do c <- readFile f
> writeFile (f ++ ".rev") $ reverseLines c
> where
> reverseLines = unlines . map reverse . lines