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!
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