[Haskell-cafe] Will changing associativity of enumerator's ($=) affect anyone? (also: enumerator mailing list)

David McBride toad3k at gmail.com
Sat Oct 15 18:49:54 CEST 2011


This would be a big boon to newbies.  When I first started using the
library I would get big errors using $= that were because I didn't
have parenthesis I needed, but didn't realize I needed, despite the
fact that the types seemed to line up.

On Sat, Oct 15, 2011 at 12:40 PM, Michael Snoyman <michael at snoyman.com> wrote:
> On Sat, Oct 15, 2011 at 4:59 PM, John Millikin <jmillikin at gmail.com> wrote:
>> A user recently suggested changing the associativity of ($=) from [[
>> infixr 0 ]] to [[ infixl 1 ]]. This allows the following expressions
>> to be equivalent:
>>
>>   run $ enumerator $$ enumeratee =$ enumeratee =$ iteratee
>>   run $ enumerator $= enumeratee $$ enumeratee =$ iteratee
>>   run $ enumerator $= enumeratee $= enumeratee $$ iteratee
>>
>> Although this is technically a backward-incompatible change, I feel
>> it's small enough that it could go in a minor release *if nobody
>> depends on the current behavior*.
>>
>> So, if anybody using 'enumerator' will have code broken by this
>> change, please speak up. If I don't hear anything in a week or so,
>> I'll assume it's all clear and will cut the new release.
>>
>> -------------------------
>>
>> Second, I was asked whether there's a mailing list for enumerator
>> stuff. To my knowledge there isn't, so I started one on librelist. To
>> subscribe and/or post, send an email to
>> haskell.enumerator at librelist.com . Archives are available at
>> http://librelist.com/browser/haskell.enumerator/ . I plan to make
>> release announcements there (for releases not important enough for
>> haskell-cafe), and it might be useful for general discussion.
>>
>
> I'm strongly in favor of this change, the current associativity has
> caused me to litter some code with a few too many parentheses.
>
> Michael
>
> _______________________________________________
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
> http://www.haskell.org/mailman/listinfo/haskell-cafe
>



More information about the Haskell-Cafe mailing list