There is a "flip" in P6, to reverse the characters in a string, and a
"reverse", to return the elements of a list. Would either of those be
an equivalent?
On 9/6/16, Trey Harris <t...@lopsa.org> wrote:
> There’s a very common functional programming pattern, usually called flip;
> its implementation in Haskell is simply:
>
> flip :: (a -> b -> c) -> b -> a -> cflip f x y = f y x
>
> Getting the same behavior out of a bespoke function in Perl 6 would be easy
> for any particular case, but writing a general version of flip that would
> work universally with all binary operators would be a pain to get right
> (while maintaining *exactly* the same behavior and errors as the original
> in all conditions), wouldn’t it?
>
> If so, R is syntactic sugar, but very helpful syntactic sugar.
>
> On Tue, Sep 6, 2016 at 12:59 PM Aaron Sherman <aaronjsher...@gmail.com>
> wrote:
>
> Oh, and note that you can pass R'd reductions as if they were normal prefix
>> ops:
>>
>> $ perl6 -e 'sub dueet(&op, *@list) { op @list }; say dueet
>> &prefix:<[R-]>,
>> 1..100'
>> -4850
>>
>>
>>
>> On Tue, Sep 6, 2016 at 12:51 PM, Aaron Sherman <aaronjsher...@gmail.com>
>> wrote:
>>
>>>
>>>
>>> $ perl6 -e 'my @numbers = 1..100; say [-] @numbers; say [R-] @numbers'
>>> -5048
>>> -4850
>>>
>>> In general, it's kind of pointless with bare infix ops, as you can just
>>> reverse the arguments, but when reducing or the like, it becomes much
>>> more
>>> valuable.
>>>
>>>
>>>
>>> On Tue, Sep 6, 2016 at 12:43 PM, Parrot Raiser <1parr...@gmail.com>
>>> wrote:
>>>
>>>> I've just stumbled across "reversed operators", e.g. say 4 R/ 12; # 3
>>>> in the documentation. I'm curious to know why the language includes
>>>> them? I'm having trouble understanding where they would be useful.
>>>>
>>>
>>>
>>
>
