On 6/15/07, Neil Mitchell
Hi Creighton,
I think Neil means here that you can't write a .cabal file, for code that uses Data.ByteString, that will work unchanged with ghc 6.4 and ghc 6.6, since the module is in a different package in each case.
Neil means he's been bitten by ByteString and Cabal many many times... :-)
After discussing with Malcolm, we think a cleaner (and potentially faster) way to go would be move to plain old String. Most of the strings in Yhc are short - something ByteString isn't particularly optimised for. String is also faster than PackedString, the only reason for PackedString was memory requirements, but that stopped being an issue years ago.
So in essence, a port from PackedString to String is probably the best way to go!
The way I'd go about this is:
1) Write a String implementation of the interface we use for PackedString
2) Start inlining the implementation manually, function by function
That way you should have relatively little work to move to String, and should be able to then patch by patch move towards a proper use of String, without doing one big change.
Okay, that sounds good.