Database.PostgreSQL.Tx.HEnv

Documentation

data family HEnv (l :: [*]) infixr 2

Glorified hlist used to construct ad hoc tx runtime environments.

Instances

Select a xs => TxEnv a (HEnv xs)

TxEnv instance for HEnv; selects the first a in the HEnv and makes it available via the runtime environment.

Since: 0.2.0.0

Defined in Database.PostgreSQL.Tx.HEnv

Methods

lookupTxEnv :: HEnv xs -> a

data HEnv ('[] :: [Type])

Defined in Database.PostgreSQL.Tx.HEnv

data HEnv ('[] :: [Type]) = Nil

data HEnv (x ': xs)

Defined in Database.PostgreSQL.Tx.HEnv

data HEnv (x ': xs) = x `Cons` (HEnv xs)

singleton :: a -> HEnv '[a]

Construct an HEnv containing a single value.

Since: 0.2.0.0

fromTuple :: FromTuple i o => i -> HEnv o

Construct an HEnv from the given tuple i. Instances support tuples of up to 16 elements.

Since: 0.2.0.0