Question

I use the hsparql library to run a query that returns german text; and thus iso-8859-1 special characters are returned.

I wrote the result of the query to a file using writeFile, but the special characters are not correctly shown. (when viewing the file with emacs)

When I instead write the output of the show function to a file, I get the following output:

["B\195\188ro", ...]

Printing out the special character it would mean: ["Büro", ....]

How can I write special characters correctly to a file? (e.g. “Büro” is correctly show in the file output.)

EDIT:
I know that show writes the escaped characters. Using writeFile directly doesn’t work, I have to check the link given in hammer’s answer to find a fix..

EDIT2:
removed, was the wrong approach.

EDIT3:
Hammers answer was right on the point. It took only 10 minutes to find the solution, but I needed to be fit and concentrated.

I looked up IO in link

The solution was (literate haskell):

> writeAllLabels = do

Running my Query (not shown, accesses the RDF TrippleStore):
>             res <- (selectStr33 (unlines qAllLabels))

>             outh <- openFile "/tmp/haskell_output.txt" WriteMode

this is the important line. If I would write "utf8" her instead of "latin1", I would get the wrong result again, i.e. as before asking the question...
>             hSetEncoding outh latin1

>             hPutStrLn outh res
>             hClose outh

Answer 1

Don’t use show if you don’t want things escaped. It’s meant for lightweight serialization and will escape a number of special characters as well as characters outside the ASCII range. If you use writeFile directly, it should work with the default encoding for your current locale.

For more fine-grained control over encodings, see the System.IO documentation.