Re: Moving ArgumentsDo forward

This gets a guilty +1 from me, I have always found $ busy and cumbersome to read. Patterns such as ‘f a b c $ do’ are ubiquitous (especially in ESDLs where clean syntax matters more) and code such as

dataFetch req = Fetch $ \ref -> do

awkwardly requires 3 steps ($, lambda, do). 2016-06-01 16:32 GMT, Edward Kmett :

Just as a note: I noticed this was being discussed a couple of weeks ago as a possible topic for haskell-prime, when they were discussing what was in scope for the committee, so I'm not entirely sure its a dead topic.

-Edward

On Wed, Jun 1, 2016 at 11:09 AM, Bardur Arantsson wrote:

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On 06/01/2016 01:48 PM, Akio Takano wrote:

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Hi,

Ticket #10843 [0] proposes an extension, ArgumentsDo, which I would love to see in GHC. It's a small syntactic extension that allows do, case, if and lambda blocks as function arguments, without parentheses. However, its differential revision [1] has been abandoned, citing a mixed response from the community. A message [2] on the ticket summarizes a thread in haskell-cafe on this topic.

I, for one, think adding this extension is worthwhile, because a significant number of people support it. Also, given how some people seem to feel ambivalent about this change, I believe actually allowing people to try it makes it clearer whether it is a good idea.

Thus I'm wondering: is there any chance that this gets merged? If so, I'm willing to work on whatever is remaining to get the change merged.

What's changed since it was last discussed? I don't think the objections were centered in the implementation, so I don't see what "whatever is remaining to get the change merged" would be.

AFAICT at best it's a *very* small improvement[1] and fractures Haskell syntax even more around extensions -- tooling etc. will need to understand even *more* syntax extensions[2].

Regards,

[1] If you grant that it is indeed an improvment, which I, personally, don't think it is.

[2] I think most people agree that this is something that should perhaps be handled by something like https://github.com/haskell/haskell-ide-engine so that it would only need to be implemented once, but there's not even an alpha release yet, so that particular objection stands, AFAICT.

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