On 07/09/2015 15:35, Simon Peyton Jones wrote:
Good start.
I have updated the page to separate the source-language design (what the programmer sees) from the implementation.
And I have included boxed sums as well – it would be deeply strange not to do so.
How did you envisage implementing anonymous boxed sums? What is their heap representation? One option is to use some kind of generic object with a dynamic number of pointers and non-pointers, and one field for the tag. The layout would need to be stored in the object. This isn't a particularly efficient representation, though. Perhaps there could be a family of smaller specialised versions for common sizes. Do we have a use case for the boxed version, or is it just for consistency? Cheers Simon
Looks good to me!
Simon
*From:*Johan Tibell [mailto:johan.tibell@gmail.com] *Sent:* 01 September 2015 18:24 *To:* Simon Peyton Jones; Simon Marlow; Ryan Newton *Cc:* ghc-devs@haskell.org *Subject:* RFC: Unpacking sum types
I have a draft design for unpacking sum types that I'd like some feedback on. In particular feedback both on:
* the writing and clarity of the proposal and
* the proposal itself.
https://ghc.haskell.org/trac/ghc/wiki/UnpackedSumTypes
-- Johan