PS I have to admit that GHC already fails to adhere to H-2010 by accepting trailing commas in module import lists, *without* a language extension. That is naughty, but I suppose it is a foot in the door. What to others think? Incidentally, trailing commas in tuples have quite a different meaning. With TupleSections, (a,,b,) means \x y -> (a,x,b,y). Simon | -----Original Message----- | From: Simon Peyton Jones | Sent: 23 September 2014 08:32 | To: 'Alexander Berntsen'; Johan Tibell | Cc: ghc-devs@haskell.org | Subject: RE: Permitting trailing commas for record syntax ADT | declarations | | | > have a language extension TrailingCommas (or something) to enable | | > the extension | | For clarification: are you overruling the "do we sneak it in HEAD or | | use pragma(s)"-vote and telling me to do the latter? | | Well, it *is* a language extension, exactly like lots of other language | extensions, isn't it? (E.g. UnicodeSyntax.) What alternative action, | exactly, are you proposing? Why do you propose to treat it differently | to other language extensions? I would be reluctant to simply add it | without any indication; then GHC would accept non-Haskell 2010 programs. | And we have not done that with other extensions. | | Simon | | | | | If we can sneak it into HEAD (this is @ you Johan, too), I suggest | | that someone applies my patches to make import and export lists | | support leading commas (presently they only support trailing commas, | | per the report) -- and following this I can just send a bunch of | | "Permit leading/trailing ',' in Foo" patches to Phabricator, and you | | guys can bikeshed over there about which ones you actually want to | | commit. ;-) | | | | If I am to go down the pragma route, I guess I can make a | | RudundantCommas pragma or something like that, that implements | | trailing commas for imports/exports, and leading/trailing commas for | | the suggestions in this thread. | | | | I'm +1 on the GHC HEAD route, but I'm not exactly violently opposed to | | the pragma route either. | | - -- | | Alexander | | alexander@plaimi.net | | https://secure.plaimi.net/~alexander | | -----BEGIN PGP SIGNATURE----- | | Version: GnuPG v2 | | Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ | | | | iF4EAREIAAYFAlQhHRoACgkQRtClrXBQc7U0WAD+Ixdah2pHMoeLiTGQJf0JLwDR | | I2dxYS7yaKyOHuHcUuEBAKh6RQmmpztz82yt/KCw0n2md3pf4n8yc5tt9s9k3FW3 | | =FfHX | | -----END PGP SIGNATURE-----