-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | Generic deserialization of PostgreSQL rows based on column names
--   
--   See README.md
@package postgresql-named
@version 0.1.0


-- | This module provides the machinery for implementing instances of
--   <a>FromRow</a> that deserialize based on the names of columns instead
--   of the positions of individual fields. This is particularly convenient
--   when deserializing to a Haskell record and you want the field names
--   and column names to match up. In this case <a>gFromRow</a> can be used
--   as a generic implementation of <a>fromRow</a>.
module Database.PostgreSQL.Simple.FromRow.Named

-- | Deserialize a type with a single record constructor by matching the
--   names of columns and record fields. Currently the complexity is
--   <i>O(n^2)</i> where n is the number of record fields.
--   
--   This is intended to be used as the implementation of <a>fromRow</a>.
--   
--   Throws
--   
--   <ul>
--   <li><a>NoSuchColumn</a> if there is a field for which there is no
--   column with the same name.</li>
--   <li><a>TooManyColumns</a> if there more columns (counting both named
--   and unnamed columns) than record fields.</li>
--   </ul>
gFromRow :: forall a modName tyName constrName fields xs. (Generic a, HasDatatypeInfo a, All2 FromField (Code a), KnownSymbol modName, KnownSymbol tyName, DatatypeInfoOf a ~ ADT modName tyName '[Record constrName fields], Code a ~ '[xs], DemoteFieldInfos fields xs) => RowParser a

-- | This is a wrapper around <a>fieldByNameWith</a> that gets the
--   <a>FieldParser</a> via the typeclass instance. Take a look at the docs
--   for <a>fieldByNameWith</a> for the details of this function.
fieldByName :: FromField a => ByteString -> RowParser a

-- | This is similar to <a>fieldWith</a> but instead of trying to
--   deserialize the field at the current position it goes through all
--   fields in the current row (starting at the beginning not the current
--   position) and tries to deserialize the first field with a matching
--   column name.
fieldByNameWith :: FieldParser a -> ByteString -> RowParser a

-- | Thrown when there is no column of the given name.
data NoSuchColumn
NoSuchColumn :: ByteString -> NoSuchColumn

-- | Thrown by <a>gFromRow</a> when trying to deserialize to a record that
--   has less fields than the current row has columns (counting both named
--   and unnamed columns).
data TooManyColumns
TooManyColumns :: !Word -> !Word -> TooManyColumns

-- | The expected number of record fields.
[numRecordFields] :: TooManyColumns -> !Word

-- | The number of columns in the row that should have been deserialized.
[numColumns] :: TooManyColumns -> !Word
instance GHC.Classes.Ord Database.PostgreSQL.Simple.FromRow.Named.TooManyColumns
instance GHC.Classes.Eq Database.PostgreSQL.Simple.FromRow.Named.TooManyColumns
instance GHC.Show.Show Database.PostgreSQL.Simple.FromRow.Named.TooManyColumns
instance GHC.Classes.Ord Database.PostgreSQL.Simple.FromRow.Named.NoSuchColumn
instance GHC.Classes.Eq Database.PostgreSQL.Simple.FromRow.Named.NoSuchColumn
instance GHC.Show.Show Database.PostgreSQL.Simple.FromRow.Named.NoSuchColumn
instance GHC.Exception.Exception Database.PostgreSQL.Simple.FromRow.Named.NoSuchColumn
instance GHC.Exception.Exception Database.PostgreSQL.Simple.FromRow.Named.TooManyColumns