[Haskell-cafe] ANNOUNCE: vector-bytestring-0.0.0.0

Mon Oct 17 11:03:04 CEST 2011

And you could just use GeneralizedNewtypeDeriving extension. Then you could
use functions from Data.Vector.Generic on your ByteStrings.
Much cleaner IMO than OverlappingInstances.

2011/10/17 Christian Maeder <Christian.Maeder at dfki.de>

> 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<rl at cse.unsw.edu.**au<rl at cse.unsw.edu.au>>
>>  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/<http://code.haskell.org/%7Ebasvandijk/>
>>> "
>>>
>> 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://v.dijk.bas@**gmail.com <v.dijk.bas at gmail.com>\">
>> v.dijk.bas at gmail.**com <v.dijk.bas at gmail.com></a></p>\n\n<p>Nick
>> on IRC:<tt>basvandijk</tt></p>\n\**n<a
>> href=\"http://www.haskellers.**com/user/basvandijk/\<http://www.haskellers.com/user/basvandijk/%5C>
>> ">\n<img
>> src=\"http://www.haskellers.**com/static/badge.png\<http://www.haskellers.com/static/badge.png%5C>"
>> \n       alt=\"I'm
>> a Haskeller\"\n       border=\"0\">\n</a>\n\n<p>See my<a
>> href=\"https://github.com/**basvandijk\<https://github.com/basvandijk%5C>">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
>>
> ,108,101,114,115,46,99,111,**109,47,115,116,97,116,105,99,**
> 47,98,97,100,103,101,46,112,**110,103,34,32,10,32,32,32,32,**
> 32,32,32,97,108,116,61,34,73,**39,109,32,97,32,72,97,115,107,**
> 101,108,108,101,114,34,10,32,**32,32,32,32,32,32,98,111,114,**
> 100,101,114,61,34,48,34,62,10,**60,47,97,62,10,10,60,112,62,**
> 83,101,101,32,109,121,32,60,**97,32,104,114,101,102,61,34,**
> 104,116,116,112,115,58,47,47,**103,105,116,104,117,98,46,99,**
> 111,109,47,98,97,115,118,97,**110,100,105,106,107,34,62,71,**
> 105,116,72,117,98,60,47,97,62,**32,112,97,103,101,32,102,111,**
> 114,32,97,32,108,105,115,116,**32,111,102,32,112,114,111,106,**
> 101,99,116,115,32,73,32,119,**111,114,107,32,111,110,46,60,**
> 47,112,62,10,10,60,47,98,111,**100,121,62,10,60,47,104,116,**
> 109,108,62,10])
>
>> 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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