Proposal: ArgumentDo

[Henrik Nilsson]

Hi all,

Joachim Breitner wrote:

 > Am Freitag, den 08.07.2016, 13:09 +0200 schrieb Sven Panne:
 > > I don't think so: https://ghc.haskell.org/trac/ghc
 > /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 cs.nott.ac.uk




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