Make List.zipWith as lazy as expected #492
Conversation
aspiwack
force-pushed
the
lazy-zipwith
branch
from
972fb7d to
08a229a
Compare
| where | ||
| go :: [a] %1 -> [b] %1 -> r | ||
| go [] [] = nil | ||
| go (a : as) [] = lefta a as |
There was a problem hiding this comment.
It's not entierely clear why the left{a,b} functions are taking head and tail as separate arguments. I guess the motivation is to make a NonEmpty list in zipWith' without having to call NonEmpty.fromList?
| (\a as -> ([], Just (Left (a :| as)))) | ||
| (\b bs -> ([], Just (Right (b :| bs)))) | ||
|
|
||
| zipWithk :: forall r a b c. (a %1 -> b %1 -> c) -> (c %1 -> r %1 -> r) -> r -> (a %1 -> [a] %1 -> r) -> (b %1 -> [b] %1 -> r) -> [a] %1 -> [b] %1 -> r |
There was a problem hiding this comment.
| zipWithk :: forall r a b c. (a %1 -> b %1 -> c) -> (c %1 -> r %1 -> r) -> r -> (a %1 -> [a] %1 -> r) -> (b %1 -> [b] %1 -> r) -> [a] %1 -> [b] %1 -> r | |
| zipWithK :: forall r a b c. (a %1 -> b %1 -> c) -> (c %1 -> r %1 -> r) -> r -> (a %1 -> [a] %1 -> r) -> (b %1 -> [b] %1 -> r) -> [a] %1 -> [b] %1 -> r |
There was a problem hiding this comment.
I think it might be better to split the argument types on several lines and document them, if this function is exported? Which I think it should be.
| Prelude.return () | ||
| where | ||
| xs :: [Word] | ||
| xs = List.zipWith (Num.+) (0 : error "bottom") [0 .. 42] |
There was a problem hiding this comment.
What is the motivation for using static bounds for ranges instead of property-supplied ones?
(same below)
| go [] (b : bs) = leftb b bs | ||
| go (a : as) (b : bs) = cons (f a b) (go as bs) | ||
|
|
||
| zipWith3 :: forall a b c d. (Consumable a, Consumable b, Consumable c) => (a %1 -> b %1 -> c %1 -> d) -> [a] %1 -> [b] %1 -> [c] %1 -> [d] |
There was a problem hiding this comment.
Why does zipWith3 doesn't get the same treatment with a zipWithK3?
| zipWithk f (:) [] consume2 consume2 | ||
| where | ||
| consume2 :: forall x y z. (Consumable x, Consumable y) => x %1 -> y %1 -> [z] | ||
| consume2 x y = x `lseq` y `lseq` [] |
There was a problem hiding this comment.
In zipWith3 you do (x, y) `lseq` [] instead, any reason to prefer one or the other?
Fixes #491