fd0b449 · rel8 · git.iko.soy

git.iko.soy/rel8

Add a `rebind` step to `alignWith` (#213)

`Rel8.Tabulate.alignWith` uses `theseTable` to recover the key, which translates to a mess of nested `CASE` expressions. This becomes exponential with repeated uses of `alignWith`. Adding a `rebind` step to `alignWith` to rewrite this `key` expression each time makes this linear.

commitfd0b449c8c1ca73e79efb8d25912b2c4801cf5c9 authorShane <shane.obrien@circuithub.com> dateTue 1 Nov 2022, 14:34 (4 years ago) parent38cbebc

1 file changed+2−1

compare with master

unifiedsplit

src/Rel8/Tabulate.hs+2−1

src/Rel8/Tabulate.hs+2−1

@@ -93,6 +93,7 @@ import Rel8.Query.Filter ( where_ )

9393import Rel8.Query.List ( catNonEmptyTable )

9494import qualified Rel8.Query.Maybe as Q ( optional )

9595import Rel8.Query.Opaleye ( mapOpaleye, unsafePeekQuery )

96+import Rel8.Query.Rebind ( rebind )

9697import Rel8.Query.These ( alignBy )

9798import Rel8.Table ( Table, fromColumns, toColumns )

9899import Rel8.Table.Aggregate ( hgroupBy, listAgg, nonEmptyAgg )

@@ -508,8 +509,8 @@ alignWith :: EqTable k

508509 -> Tabulation k a -> Tabulation k b -> Tabulation k c

509510alignWith f (Tabulation as) (Tabulation bs) = Tabulation $ \p -> do

510511 tkab <- liftF2 (alignBy condition) as bs p

512+ k <- traverse (rebind "key") $ recover $ bimap fst fst tkab

511513 let

512− k = recover $ bimap fst fst tkab

513514 tab = bimap snd snd tkab

514515 pure (k, f tab)

515516 where