ByteString’s “lines” eats empty lines

[guest]

I’d expect this to be true for ByteStrings? map B.unpack . B.lines . B.pack == Prelude.lines But it seems that B.lines will merge several consecutive newlines. B.split '\n' works as it should, though.

Thanks, Joachim

[mail@…]

Just addding my e-Mail-Adress

[igloo]

In particular, it's Lazy.Char8 that has the problem. Here's the (libraries/base) HEAD:

Prelude> lines "a\n\nb\n\nc"
["a","","b","","c"]
Prelude> :m - Prelude
> :m + Data.ByteString.Char8
Data.ByteString.Char8> Prelude.map unpack (lines (pack "a\n\nb\n\nc"))
["a","","b","","c"]
Data.ByteString.Char8> :m - Data.ByteString.Char8
> :m + Data.ByteString.Lazy.Char8
Data.ByteString.Lazy.Char8> Prelude.map unpack (lines (pack "a\n\nb\n\nc"))
["a","b","c"]

I haven't looked at the development branch of fps/bytestring.

[igloo]

Presumably this will be fixed in the new bytestring package?

[duncan]

Yes it will be fixed in the new bytestring package.

[igloo]

Fixed by Duncan:

Mon Aug 27 16:23:45 BST 2007  Duncan Coutts <duncan@haskell.org>
  * Fix Lazy.lines "foo\n\nbar"

and now tested by bytestring006.