Proposal: ArgumentDo

Iavor Diatchki iavor.diatchki at
Fri Jul 8 16:42:24 UTC 2016


while  we are voting here, I kind of like this proposal, so +1 for me.

I understand that some of the examples look strange to Haskell old-timers
but, as Joachim points out, the behavior is very consistent.   Besides, the
"Less Obvious Examples" were selected so that they are, well, less obvious.
  The common use cases (as in ticket #10843) seem quite appealing, at least
to me, and not at all confusing.  But, then, I also like the
records-with-no-parens notation :-)


On Fri, Jul 8, 2016 at 5:03 AM, Aloïs Cochard <alois.cochard at>

> -1 for same reasons.
> On 8 July 2016 at 14:00, Henrik Nilsson <Henrik.Nilsson at>
> wrote:
>> Hi all,
>> Joachim Breitner wrote:
>> > Am Freitag, den 08.07.2016, 13:09 +0200 schrieb Sven Panne:
>> > > I don't think so:
>> > /wiki/ArgumentDo#Bl
>> > [...]
>> > Where is the outer set of parenthesis coming from?
>> >
>> > This is all not related to the ArgumentDo notation. Note that [...]
>> The very fact that that experts can't easily agree on how a small
>> Haskell fragment is parsed to me just confirms that Haskell already
>> is a syntactically very cumbersome language.
>> The present proposal just makes matters worse. For that reason
>> alone, I don't find it compelling at all. (So -1 from me, then.)
>> I will not repeat the many other strong arguments against that has been
>> made. But I must say I don't find the use cases as documented
>> on the associated web page compelling at all. Maybe there is a tacit
>> desire to be able to pretend functions are keywords for various
>> creative uses in supporting EDSLs and such. But for that to be truly
>> useful, one need to support groups of related keywords. Something
>> like Agda's mixfix syntax springs to mind. But this proposal does
>> not come close, so the benefits are minimal and the drawbacks large.
>> As a final point, the inherent asymmetry of the proposal (the
>> last argument position is special as, for certain kinds of
>> expressions, parentheses may be omitted there but not elsewhere)
>> is also deeply unsettling.
>> Best,
>> /Henrik
>> --
>> Henrik Nilsson
>> School of Computer Science
>> The University of Nottingham
>> nhn at
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