I think the cleanest solution (just from a theoretical point of view) is
to use a newtype for your byte strings.
- it should have the same performance
- allows to make ByteString really abstract when hiding the newtype
constructor
- is portable and supplies control over all other instances (not just Show)
I'm not sure if one could make really bad thinks to your ByteString by
using the Vector interface, but one would want to disallow vector
operations just for compatible with other byte strings.
It would require more work just on your side, though.
Cheers Christian
Am 15.10.2011 16:15, schrieb Bas van Dijk:
On 15 October 2011 13:34, Roman Leshchinskiy<[email protected]> wrote:
On 15/10/2011, at 12:26, Roman Leshchinskiy wrote:
On 14/10/2011, at 12:37, Bas van Dijk wrote:
If there's need for a specific Show instance for Vectors of Word8s we
can always add one directly to vector. (Roman, what are your thoughts
on this?)
Personally, I think that ByteString and especially Vector Word8 aren't strings
and shouldn't be treated as such. But I wouldn't be strongly against showing
them as strings. However, I *am* strongly against using UndecidableInstances in
vector and I don't see how to implement this without using them.
I meant OverlappingInstances, of course. To clarify, I would still consider it
if everybody thinks it's a really good idea.
Roman
I agree that you shouldn't use ByteStrings or Vectors of Word8s for
Unicode strings. However I can imagine that for quick sessions in ghci
it can be quite handy if they are shown as strings. For example,
currently we have:
import Network.HTTP.Enumerator
simpleHttp "http://code.haskell.org/~basvandijk/";
Chunk "<html>\n<head><title>Bas van
Dijk</title></head>\n<body>\n<h1>Bas van Dijk</h1>\n\n<p>Email:<a
href=\"mailto://[email protected]\";>[email protected]</a></p>\n\n<p>Nick
on IRC:<tt>basvandijk</tt></p>\n\n<a
href=\"http://www.haskellers.com/user/basvandijk/\";>\n<img
src=\"http://www.haskellers.com/static/badge.png\"; \n alt=\"I'm
a Haskeller\"\n border=\"0\">\n</a>\n\n<p>See my<a
href=\"https://github.com/basvandijk\";>GitHub</a> page for a list of
projects I work on.</p>\n\n</body>\n</html>\n" Empty
If ByteStrings were not shown as strings this would look like:
Chunk ( fromList
[60,104,116,109,108,62,10,60,104,101,97,100,62,60,116,105,116,108,101,62,66,97,115,32,118,97,110,32,68,105,106,107,60,47,116,105,116,108,101,62,60,47,104,101,97,100,62,10,60,98,111,100,121,62,10,60,104,49,62,66,97,115,32,118,97,110,32,68,105,106,107,60,47,104,49,62,10,10,60,112,62,69,109,97,105,108,58,32,60,97,32,104,114,101,102,61,34,109,97,105,108,116,111,58,47,47,118,46,100,105,106,107,46,98,97,115,64,103,109,97,105,108,46,99,111,109,34,62,118,46,100,105,106,107,46,98,97,115,64,103,109,97,105,108,46,99,111,109,60,47,97,62,60,47,112,62,10,10,60,112,62,78,105,99,107,32,111,110,32,73,82,67,58,32,60,116,116,62,98,97,115,118,97,110,100,105,106,107,60,47,116,116,62,60,47,112,62,10,10,60,97,32,104,114,101,102,61,34,104,116,116,112,58,47,47,119,119,119,46,104,97,115,107,101,108,108,101,114,115,46,99,111,109,47,117,115,101,114,47,98,97,115,118,97,110,100,105,106,107,47,34,62,10,32,32,60,105,109,103,32,115,114,99,61,34,104,116,116,112,58,47,47,119,119,119,46,104,97,115,107,101,108
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
Empty
Personally, I don't work in ghci that often so I don't care that much
if we have or don't have specialized Show instances for Vectors of
Word8s.
So what do other people think about this?
Bas
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