Well, for your example frustration, the leading comma style would sort your problem nicely. As for the particulars… hmm, not sure. I use leading commas for both, so I never really noticed. It may be that since modules simply expose functions to other programs, the form is syntactically irrelevant except when the module is being loaded. I am quite curious about it now, though, so I hope there are some more knowledgeable folks with some input. On Jul 11, 2011, at 4:49 AM, L Corbijn wrote:

Hello,

I'm wondering why the trailing comma is allowed in export syntax, but not in record syntax, here an example module Foo ( export1, -- is allowed ) where

data Type = Type { record1 :: Foo, -- is not allowed }

To me this seems quite inconsistent and sometimes quite frustrating, imagine the case that you want to temporarily remove the last record: data Type = Type { record1 :: Foo, -- record2 :: Bar } this would fail due to an extra comma that has to be commented out.

You could of course say that I'm using a bad style, but it remains that it seems to be inconsistent to allow a trailing comma in one place and not in the other. So is there an reason for this?

Lars Corbijn _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

On 11 July 2011 10:49, L Corbijn wrote:

You could of course say that I'm using a bad style, but it remains that it seems to be inconsistent to allow a trailing comma in one place and not in the other. So is there an reason for this?

I've also noticed that I can write data X = X deriving Show But not import Prelude hiding print But we can write x :: Foo x => … x :: (Foo x) => … Can write class X But not module X I wouldn't expect that there are particular argued reasons for these inconsistencies. It's difficult to balance a consistent syntax in a language while trying to be convenient. I don't think it matters too much.