[Haskell-cafe] Syntax proposal for "reverse apply"/"pipeline apply" (flip ($))
ekmett at gmail.com
Thu Apr 17 19:56:29 UTC 2014
The choice of fixity came about because actually the most common thing
replaced by (<&>) is actually (>>=), when the thing you are binding to no
longer has an effect, not actually (<$>), despite what the name suggests.
This made a non-trivial difference in the amount of parentheses in real
code, and was a conscious decision, so reverting it is not something I
would do lightly and breaks real code.
Back during the discussion of whether we should adopt (&), (<&>) also came
up, but with only one voice in favor, and nobody else really feeling
passionately, and with various colors like this available for the bikeshed
it was dropped.
On Thu, Apr 17, 2014 at 3:32 PM, Hans Höglund <hans at hanshoglund.se> wrote:
> Can we argue about the fixity for (<&>)? I've always it as infixl 4, to
> mix it in with other applicative operators, e.g.:
> (:) <$> fx <*> fl
> fx <&> (:) <*> fl
> I agree, this seems to be a mistake in lens.
> Last I checked,
>> (&) = flip ($)
>> is both shorter to type, and more explicit than:
>> import Control.Apply.Reverse
>> - Clark
> Well the purpose here is to propose a standard name and fixity, not to
> save keystrokes.
> When a lot of libraries start to define a (trivial) thing under different
> names, that to me is a good indication that it should be in the standard
> library. It is a matter of keeping the signal-to-noise ratio large, which
> greatly helps when reading unfamiliar code.
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
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