{-# language FlexibleContexts #-}

module Rel8.Query.Each
  ( each
  )
where

-- base
import Prelude

-- opaleye
import qualified Opaleye.Table as Opaleye

-- rel8
import Rel8.Query ( Query )
import Rel8.Query.Opaleye ( fromOpaleye )
import Rel8.Schema.Name ( Selects )
import Rel8.Schema.Table ( TableSchema )
import Rel8.Table ( fromColumns, toColumns )
import Rel8.Table.Opaleye ( table, unpackspec )


-- | Select each row from a table definition. This is equivalent to @FROM
-- table@.
--
-- >>> mapM_ print =<< select c (each projectSchema)
-- Project {projectAuthorId = 1, projectName = "rel8"}
-- Project {projectAuthorId = 2, projectName = "aeson"}
-- Project {projectAuthorId = 2, projectName = "text"}
each :: Selects names exprs => TableSchema names -> Query exprs
each =
  fmap fromColumns .
  fromOpaleye .
  Opaleye.selectTableExplicit unpackspec .
  table .
  fmap toColumns