relational-query: simplify module dependency. projecting interface.

relational-query/src/Database/Relational/Query/Internal/Sub.hs

@@ -21,7 +21,8 @@ module Database.Relational.Query.Internal.Sub
        , ProductTreeBuilder, ProductBuilder
 
        , UntypedProjection, untypedProjectionWidth, ProjectionUnit (..)
-       , Projection, untypeProjection, typedProjection, projectionWidth, projectFromColumns
+       , Projection, untypeProjection, typedProjection, projectionWidth
+       , projectFromColumns, projectFromScalarSubQuery
 
          -- * Query restriction
        , QueryRestriction
@@ -138,6 +139,10 @@ projectFromColumns :: [ColumnSQL]    -- ^ SQL string list specifies columns
                    -> Projection c r -- ^ Result 'Projection'
 projectFromColumns =  typedProjection . map RawColumn
 
+-- | Unsafely generate 'Projection' from scalar sub-query.
+projectFromScalarSubQuery :: SubQuery -> Projection c t
+projectFromScalarSubQuery = typedProjection . (:[]) . Scalar
+
 
 -- | Type for restriction of query.
 type QueryRestriction c = [Projection c (Maybe Bool)]

relational-query/src/Database/Relational/Query/Projection.hs

@@ -61,7 +61,7 @@ import Database.Relational.Query.Pi (Pi)
 import qualified Database.Relational.Query.Pi.Unsafe as UnsafePi
 import Database.Relational.Query.Sub
   (projectionColumns,
-   untypedProjectionFromJoinedSubQuery, untypedProjectionFromScalarSubQuery,
+   untypedProjectionFromJoinedSubQuery,
    unsafeProjectionStringSql)
 import qualified Database.Relational.Query.Sub as SubQuery
 
@@ -90,7 +90,7 @@ unsafeFromQualifiedSubQuery =  typedProjection . untypedProjectionFromJoinedSubQ
 
 -- | Unsafely generate 'Projection' from scalar sub-query.
 unsafeFromScalarSubQuery :: SubQuery -> Projection c t
-unsafeFromScalarSubQuery =  typedProjection . untypedProjectionFromScalarSubQuery
+unsafeFromScalarSubQuery = Internal.projectFromScalarSubQuery
 
 -- | Unsafely generate unqualified 'Projection' from 'Table'.
 unsafeFromTable :: Table r

relational-query/src/Database/Relational/Query/Sub.hs

@@ -30,12 +30,12 @@ module Database.Relational.Query.Sub (
   -- * Projection
   Projection, ProjectionUnit, UntypedProjection,
 
-  untypedProjectionFromJoinedSubQuery, untypedProjectionFromScalarSubQuery,
+  untypedProjectionFromJoinedSubQuery,
 
   projectionColumns, unsafeProjectionStringSql,
 
   -- deprecated interfaces
-  untypedProjectionFromColumns,
+  untypedProjectionFromColumns, untypedProjectionFromScalarSubQuery,
   unsafeProjectFromColumns,
   widthOfUntypedProjection, columnsOfUntypedProjection,
 
@@ -256,6 +256,7 @@ column qs =  d (Internal.unQualify qs)  where
 untypedProjectionFromColumns :: [ColumnSQL] -> UntypedProjection
 untypedProjectionFromColumns =  map RawColumn
 
+{-# DEPRECATED untypedProjectionFromScalarSubQuery "prepare to drop public interface. use ( (:[]) . Scalar )." #-}
 -- | Make untyped projection from scalar sub-query.
 untypedProjectionFromScalarSubQuery :: SubQuery -> UntypedProjection
 untypedProjectionFromScalarSubQuery = (:[]) . Scalar