[Haskell-cafe] Inconsistent trailing comma in export list and record syntax

[Henning Thielemann]

On Mon, 11 Jul 2011, Johan Tibell wrote:

> On Mon, Jul 11, 2011 at 3:54 PM, Henning Thielemann
> <thunderbird at henning-thielemann.de> wrote:
>> Johan Tibell wrote:
>>> I've found this quite annoying, especially when using CPP to
>>> conditionally include something in a list, as it might force you to
>>> reorder the list to make the commas appear correctly when the
>>> conditional section is enabled/disabled.
>>
>> In this case I use the colon like a terminator.
>>
>> http://www.haskell.org/haskellwiki/List_notation
>
> Sorry, I wasn't being clear. I meant for import/export lists.

But in import/export lists you can use the trailing comma, and thus you 
can conditionally export or import identifiers at any position. However, 
the trailing comma is forbidden in enumerations of constructors. E.g.

import M (R, S, T, )

is allowed, but not

import M (T(A,B,C,))