On 05/06/2016 06:34 PM, Iavor Diatchki wrote: [--snip--]
By the way, leading/trailing separators conflict with the syntax for tuple sections:
(True,) :: t -> (Bool, t) (,True) :: t -> (t, Bool)
I think that it wold be quite odd if leading/trailing commas meant one thing in tuples and something completely different in lists.
[--snip--] (I'm not on the committee or even close, just be absolutely clear from the start.) While I have a) *NEVER*... *EVER* seen TupleSections in the wild[1], and b) I really, really want to have an "ignore-trailing-comma" rule for lists, I must say that this is a situation where backward-compat and the Principle of Least Surpise[2] probably rule the day. I'm certainly be open to persuasion, but that would probably mean deprecating TupleSections, and I'm not sure how popular that would be. (And would perhaps require *two* iterations of the Haskell standard to achieve. I suppose an exception could be made if a "go fix" type tool could be developed, but I'm not sure that's something the Standards committe should concern themselves with... but it *would* be able to move the language towards much faster evolution, FWIW. I wish we had hfix.) Regards, [1] Didn't even know they existed until the recent thread on Reddit. [2] That is, it would be surprising if lists and tuples worked differently in this respect.