Re: proposal for trailing comma and semicolon
On Tue, Aug 13, 2013 at 09:47:49PM +0100, Simon Marlow wrote: On 17/05/13 20:01, Ian Lynagh wrote: I'd be in favour of allowing a trailing or leading comma anywhere that comma is used as a separator. TupleSections would need to be changed or removed, though. The type constructors for tuples look like (,,,), so they would have to be a special case. Ugh, true. I'd much rather leave tuples out of it: the precise number of commas in a tuple is significant. It would be rather unpleasant to have [1,2,3,] ::[Int] (1,2,3,) :: Int - (Int, Int, Int, Int) Thanks Ian ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: proposal for trailing comma and semicolon
On 17/05/13 20:01, Ian Lynagh wrote: I'd be in favour of allowing a trailing or leading comma anywhere that comma is used as a separator. TupleSections would need to be changed or removed, though. The type constructors for tuples look like (,,,), so they would have to be a special case. I'd much rather leave tuples out of it: the precise number of commas in a tuple is significant. Cheers, Simon ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: proposal for trailing comma and semicolon
Same with me. I like using them, but turning on a language extension feels excessive. I use them sometimes, but would do that much more if they didn't require adding an extension. Roman * Edward Kmett ekm...@gmail.com [2013-05-17 15:24:27-0400] I personally use tuple sections a fair bit, though admittedly mostly for simple (,a) or (a,) cases. On Fri, May 17, 2013 at 3:01 PM, Ian Lynagh i...@well-typed.com wrote: On Fri, May 17, 2013 at 02:04:44PM -0400, Edward Kmett wrote: My main concern is its a really weird corner case for the grammar to remember for tuple sections and it does have very weird grammar specification issues. Tuple sections could look like (True, _) rather than (True,) Does anyone know how common tuple sections are, incidentally? They've been around since GHC 6.12, so it would be interesting to know if people are actually using them. ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: proposal for trailing comma and semicolon
On Fri, May 17, 2013 at 11:37:29AM -0700, Greg Weber wrote:
I would rather get rid of commas
altogether (make them optional actually) and just have a newline +
consistent indentation signal a new list item: coffee-script does that.
I'm interested in this idea. We should make sure we think it through and
there are no weird cases, but if it all works out I'd be in favour.
This looks a bit too much like a GADT to my eyes:
data Point = MkPoint
x :: Rational
y :: Rational
Maybe the recommended style would be:
data Point =
MkPoint
x :: Rational
y :: Rational
But I suppose pattern-matching, update syntax and so forth would
probably still have to use explicit braces and commas. That
inconsistency is probably a bit unpleasant.
I'd say import and export lists at least are probably fine with a
layout-based rule.
On Fri, May 17, 2013 at 11:23 AM, Tillmann Rendel
ren...@informatik.uni-marburg.de wrote:
Hi,
Garrett Mitchener wrote:
There's a weird idiom that I see all the time in Haskell code where
coders put commas at the beginning of lines:
data Thing = Thing {
x :: Int
,y :: Int
,z :: Int
,foo :: String
} ...
items = [
red
,blue
,green
]
(I don't think this is valid Haskell. The closing } and ] should be more
indented).
I like to put commas at the beginning of lines, because there, I can make
them line up and it is visually clear that they are all at the same nesting
level. I like how the commas look a bit like bullet points. For example, I
would write:
items =
[ red
, blue
, green
]
Could we extend Garett's proposal to also allow prefixing the first
element of a list with a comma, to support this style:
items = [
, red
, blue
, green
]
Allowing an optional extra comma both at the beginning and at the end
would allow programmers the choice where they want to put their commas.
Tillmann
__**_
Haskell-prime mailing list
Haskell-prime@haskell.org
http://www.haskell.org/**mailman/listinfo/haskell-primehttp://www.haskell.org/mailman/listinfo/haskell-prime
___
Haskell-prime mailing list
Haskell-prime@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-prime
___
Haskell-prime mailing list
Haskell-prime@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-prime
Re: proposal for trailing comma and semicolon
Greg Weber wrote: I would rather get rid of commas altogether (make them optional actually) and just have a newline + consistent indentation signal a new list item: coffee-script does that. That would go well together with allowing extra commas, because in explicit block syntax, we can have extra semicolons. Ben Millwood wrote: This looks a bit too much like a GADT to my eyes: data Point = MkPoint x :: Rational y :: Rational I fear that this is confusing, because so far, layout is always introduced by a keyword. But here, layout is introduced by an identifier. I suspect this is also what makes problems below for update syntax etc. But I suppose pattern-matching, update syntax and so forth would probably still have to use explicit braces and commas. That inconsistency is probably a bit unpleasant. I feel that record (definition | matching | literals | update) should all use the same syntax. I'd say import and export lists at least are probably fine with a layout-based rule. What about list literals? items = new-keyword-here red blue green Again, I don't see how that can work out without introducing a keyword. Maybe reusing data would work: items = data red blue green :) Tillmann ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: proposal for trailing comma and semicolon
On Fri, May 17, 2013 at 9:17 AM, Garrett Mitchener garrett.mitche...@gmail.com wrote: Anyway, this is a paper cut in the language that has been bugging me for a while, and since there's now a call for suggestions for Haskell 2014, I thought I'd ask about it. I've also thought about this issue and I agree with Garrett, allowing that trailing comma (or semicolon) would help readability*. If it doesn't work with tuples, perhaps we could at least do it with lists and records? * It also hurts source control diffs a bit, as adding extra commas will give diffs that suggest that one additional line was changed. -- Johan ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: proposal for trailing comma and semicolon
On 05/17/2013 06:32 PM, Johan Tibell wrote: On Fri, May 17, 2013 at 9:17 AM, Garrett Mitchener garrett.mitche...@gmail.com wrote: Anyway, this is a paper cut in the language that has been bugging me for a while, and since there's now a call for suggestions for Haskell 2014, I thought I'd ask about it. I've also thought about this issue and I agree with Garrett, allowing that trailing comma (or semicolon) would help readability*. If it doesn't work with tuples, perhaps we could at least do it with lists and records? Multiline tuples don't seem all that common, so +1 on that from me. ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: proposal for trailing comma and semicolon
My main concern is its a really weird corner case for the grammar to remember for tuple sections and it does have very weird grammar specification issues. I really have no objection to it for the other cases. It'd make export lists cleaner, maybe a few other cases, but how often can you really say you can meaningfully comment out one field of a tuple have have the surrounding code make any sense? -Edward On Fri, May 17, 2013 at 12:35 PM, Bardur Arantsson s...@scientician.netwrote: On 05/17/2013 06:32 PM, Johan Tibell wrote: On Fri, May 17, 2013 at 9:17 AM, Garrett Mitchener garrett.mitche...@gmail.com wrote: Anyway, this is a paper cut in the language that has been bugging me for a while, and since there's now a call for suggestions for Haskell 2014, I thought I'd ask about it. I've also thought about this issue and I agree with Garrett, allowing that trailing comma (or semicolon) would help readability*. If it doesn't work with tuples, perhaps we could at least do it with lists and records? Multiline tuples don't seem all that common, so +1 on that from me. ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: proposal for trailing comma and semicolon
Hi,
Garrett Mitchener wrote:
There's a weird idiom that I see all the time in Haskell code where
coders put commas at the beginning of lines:
data Thing = Thing {
x :: Int
,y :: Int
,z :: Int
,foo :: String
} ...
items = [
red
,blue
,green
]
(I don't think this is valid Haskell. The closing } and ] should be more
indented).
I like to put commas at the beginning of lines, because there, I can
make them line up and it is visually clear that they are all at the same
nesting level. I like how the commas look a bit like bullet points. For
example, I would write:
items =
[ red
, blue
, green
]
Could we extend Garett's proposal to also allow prefixing the first
element of a list with a comma, to support this style:
items = [
, red
, blue
, green
]
Allowing an optional extra comma both at the beginning and at the end
would allow programmers the choice where they want to put their commas.
Tillmann
___
Haskell-prime mailing list
Haskell-prime@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-prime
Re: proposal for trailing comma and semicolon
I use them sometimes, but would do that much more if they didn't require adding an extension. Roman * Edward Kmett ekm...@gmail.com [2013-05-17 15:24:27-0400] I personally use tuple sections a fair bit, though admittedly mostly for simple (,a) or (a,) cases. On Fri, May 17, 2013 at 3:01 PM, Ian Lynagh i...@well-typed.com wrote: On Fri, May 17, 2013 at 02:04:44PM -0400, Edward Kmett wrote: My main concern is its a really weird corner case for the grammar to remember for tuple sections and it does have very weird grammar specification issues. Tuple sections could look like (True, _) rather than (True,) Does anyone know how common tuple sections are, incidentally? They've been around since GHC 6.12, so it would be interesting to know if people are actually using them. I really have no objection to it for the other cases. It'd make export lists cleaner, Actually, you are already allowed an extra trailing comma in import and export lists. maybe a few other cases, but how often can you really say you can meaningfully comment out one field of a tuple have have the surrounding code make any sense? It happens occasionally, especially when simplifying code while debugging. Commenting out list items is much more common, though. I'd be in favour of allowing a trailing or leading comma anywhere that comma is used as a separator. TupleSections would need to be changed or removed, though. Thanks Ian -- Ian Lynagh, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/ ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
