On 5 April 2011 07:04, Mark Lentczner
I'm not on that mailing list, so I'll comment here:
I recommend joining the prime list. It is very low traffic and the place where language changes should be discussed.
My only caveat is that the encoding provision should apply when Haskell source is presented to the compiler as a bare stream of octets. Where Haskell source is interchanged as a stream of Unicode characters, then encoding is not relevant -- but may be likely governed by some outer protocol - and hence may not be UTF-8 but nonetheless invisible at the Haskell level.
My intention is that every time you need an encoding for Haskell sources, it must be UTF-8. At least if you want to call it Haskell. This is not limited to compilers but concerns all tools that process Haskell sources.
Two examples where this might come into play are: 1) An IDE that stores module source in some database. It would not be relevant what encoding that IDE and database choose to store the source in if the source is presented to the integrated compiler as Unicode characters.
An IDE and database are free to store sources any way they see fit. But as soon as you want to exchange that source with some standards conforming system it must be encoded as UTF-8.
2) If a compilation system fetches module source via HTTP (I could imagine a compiler that chased down included modules directly off of Hackage, say), then HTTP already has a mechanism (via MIME types) of transmitting the encoding clearly. As such, there should be no problem if that outer protocol (HTTP) transmits the source to the compiler via some other encoding. There is no reason (and only potential interoperability restrictions) to enforce that UTF-8 be the only legal encoding here.
This is an interesting example. What distinguishes this scenario from others is that there is a clear understanding between two parties (client and server) how a file should be interpreted. I could word my proposal in such a way that it only concerns situations where such a prior agreement doesn't or can't exist. For example, when storing source on a file system.