Add Rel8.Tabulate, a complementary API for writing queries

circuithub · Jul 14, 2021 · 40f9758 · 40f9758
1 parent b44ea81
commit 40f9758
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diff --git a/rel8.cabal b/rel8.cabal
@@ -21,13 +21,15 @@ library
   build-depends:
       aeson
     , base ^>= 4.14 || ^>=4.15
+    , bifunctors
     , bytestring
     , case-insensitive
     , comonad
     , contravariant
     , hasql ^>= 1.4.5.1
     , opaleye ^>= 0.7.3.0
     , profunctors
+    , product-profunctors
     , scientific
     , semialign
     , semigroupoids
@@ -51,6 +53,7 @@ library
     Rel8.Expr.Num
     Rel8.Expr.Text
     Rel8.Expr.Time
+    Rel8.Tabulate
 
   other-modules:
     Rel8.Aggregate

diff --git a/src/Rel8/Query.hs b/src/Rel8/Query.hs
@@ -23,10 +23,12 @@ import qualified Opaleye.Internal.Tag as Opaleye
 import Rel8.Query.Set ( unionAll )
 import Rel8.Query.Opaleye ( fromOpaleye )
 import Rel8.Query.Values ( values )
+import Rel8.Table ( fromColumns, toColumns )
 import Rel8.Table.Alternative
   ( AltTable, (<|>:)
   , AlternativeTable, emptyTable
   )
+import Rel8.Table.Projection ( Projectable, apply, project )
 
 -- semigroupoids
 import Data.Functor.Apply ( Apply, (<.>) )
@@ -151,6 +153,10 @@ newtype Query a =
   )
 
 
+instance Projectable Query where
+  project f = fmap (fromColumns . apply f . toColumns)
+
+
 instance Functor Query where
   fmap f (Query a) = Query (fmap (fmap (fmap f)) a)