On 12-04-24 10:11 PM, wren ng thornton wrote:
To the extent that ByteString's instance runs into issues with high point codes, that strikes me as a bug in virtue of poor foresight. Consider, for instance, the distinction between integral and non-integral numeric literals. We recognize that (0.1 :: Int) is invalid, and so we a-priori define the Haskell syntax to recognize two different sorts of "numbers". It seems that we should do the same thing for strings. 'String' literals of raw binary goop (subject to escape mechanisms for detecting the end of string) are different from string literals which are valid Unicode sequences. This, I think, is fair game to be expressed directly in the specification of overloaded string literals, just as we distinguish classes of overloaded numeric literals. Unfortunately, for numeric literals we have a nice syntactic distinction between integral and non-integral, which seems to suggest that we'd need a similar syntactic distinction to recognize the different sorts of string literals.
I have a cunning plan: class IsList c e | c -> e where fromList :: [e] -> c -- requirement: must be a total function instance IsList ByteString Word8 where fromList = ByteString.pack instance Ord e => IsList (Set e) e where fromList = Set.fromList {-# LANGUAGE OverloadedList #-} example1 :: ByteString example1 = [106,117,115,116,32,107,105,100,100,105,110,103] example2 :: Set Word8 example2 = [106,117,115,116,32,107,105,100,100,105,110,103] Please don't kill me!