Hi Luke,<br><br> <a href="http://cvs.haskell.org/Hugs/pages/libraries/base/Data-ByteString.html#v%3Ajoin">join</a> :: <a href="http://cvs.haskell.org/Hugs/pages/libraries/base/Data-ByteString.html#t%3AByteString">ByteString</a> -> [<a href="http://cvs.haskell.org/Hugs/pages/libraries/base/Data-ByteString.html#t%3AByteString">ByteString</a>] -> <a href="http://cvs.haskell.org/Hugs/pages/libraries/base/Data-ByteString.html#t%3AByteString">ByteString</a> ???<br>
<br>Vasili<br><br><div class="gmail_quote">On Sat, Dec 27, 2008 at 1:58 AM, Luke Palmer <span dir="ltr"><<a href="mailto:lrpalmer@gmail.com">lrpalmer@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="gmail_quote">2008/12/26 Galchin, Vasili <span dir="ltr"><<a href="mailto:vigalchin@gmail.com" target="_blank">vigalchin@gmail.com</a>></span><div><div></div><div class="Wj3C7c"><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hello, <br><br> I have a ByteString -> [ByteString] -> ByteString situation, i.e. concatenation .....<br><br><br> -- marshall into ByteString representation<br> join<br>
(encode (buildHeader ss)) -- ByteString<br>
(map encode (buildEntries (sequenceListExtract ss))) -- [ByteString]<br> <br><br>I get the following typecheck error which is vexing me ....<br><br> Couldn't match expected type `t -> t -> B.ByteString'<br>
against inferred type `B.ByteString'<br><br>???</blockquote><div><br></div></div></div><div>join is not a function in Data.ByteString. By the error I'm guessing you're getting the join from Control.Monad, instantiated to (->).</div>
<div><br></div><div>You are looking for "concat"; i.e.</div><div><br></div><div> concat $ <div class="Ih2E3d"><br> encode (buildHeader ss) : -- ByteString<br>
map encode (buildEntries (sequenceListExtract ss)) -- [ByteString]<br>
</div></div><div><br></div><div>(Control.Monad.join does end up meaning"concat" when working on lists of lists, but it does not generalize to lists of other things).</div><div><br></div><font color="#888888"><div>
Luke</div></font></div>
</blockquote></div><br>