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


-- | Entity based records
--   
--   Usage: <a>http://github.com/nonowarn/has/blob/master/README.md</a>
--   
--   And its examples and test would be helpful:
--   
--   <ul>
--   <li><a>http://github.com/nonowarn/has/tree/master/examples/</a></li>
--   
--   <li><a>http://github.com/nonowarn/has/blob/master/test/Main.hs</a></li>
--   </ul>
@package has
@version 0.4


-- | Entiry based records.
module Data.Has

-- | Same as <tt>Knows lab (TypeOf lab) s</tt>, Useful on writing type
--   signitures.
--   
--   Holds <tt>e == (lab .^ (lab ^= e $ s))</tt> where <tt>lab :: lab; e ::
--   TypeOf lab; s :: s</tt>
class (Knows lab (TypeOf lab) s) => Has lab s

-- | <tt>Field a</tt> is a type list which contains only one element of
--   <tt>a</tt>. And every field in the records should be this type.
type Field a = a ::: TyNil

-- | Concatenates between <a>Field</a>s or records. Records are
--   concatenated rows. For example, Following expressions are valid.
--   
--   <pre>
--   -- Concatenation of rows (i.e. record)
--   field "string" &amp; field True
--   </pre>
--   
--   <pre>
--   -- Concatenation of records
--   (field 'c' &amp; field ()) &amp; (field False &amp; field "string")
--   </pre>
--   
--   <pre>
--   -- ... And concatenations between a field and a record
--   field () &amp; (field False &amp; field "string")
--   (field 'c' &amp; field ()) &amp; field False
--   </pre>
(&) :: (Append a b) => a -> b -> a :&: b

-- | Represents concatenated rows or records.

-- | Creates a <a>Field</a> of <tt>a</tt>.
field :: a -> Field a

-- | Strict version of <a>injl</a>
(^=) :: (Knows lab (TypeOf lab) s) => lab -> TypeOf lab -> s -> s

-- | Strict version of <a>prjl</a>
(^.) :: (Knows lab (TypeOf lab) s) => lab -> s -> TypeOf lab

-- | Strict version of <a>updl</a>
(^:) :: (Knows lab (TypeOf lab) s) => lab -> (TypeOf lab -> TypeOf lab) -> (s -> s)

-- | Injects and Projects a labelled values into records.
class (Contains (Labelled lab e) s) => Knows lab e s | lab s -> e
injl :: (Knows lab e s) => lab -> e -> s -> s
prjl :: (Knows lab e s) => lab -> s -> e

-- | Updates a labelled value
updl :: (Knows lab b a) => lab -> (b -> b) -> (a -> a)

-- | Represents labelled value.
data Labelled lab a

-- | Represents labelled field.
type :> lab a = Field (Labelled lab a)

-- | Makes a labelled field.
(.>) :: lab -> a -> lab :> a

-- | TypeOf <tt>a</tt> should indicate a type labelled by <tt>a</tt>

-- | <pre>
--   FieldOf a == a :&gt; TypeOf a
--   </pre>

-- | Creates a field labelled by <tt>a</tt>
fieldOf :: TypeOf a -> FieldOf a

-- | Cons a type onto type-list.
data (:::) a b

-- | The empty type-list.
data TyNil

-- | Provides injection and projection into type lists.
--   
--   Holds <tt>e == prj (inj e s)</tt> for all <tt>s</tt> and <tt>e</tt>.
class Contains e s
instance (Eq a) => Eq (Labelled lab a)
instance (Ord a) => Ord (Labelled lab a)
instance (Show a) => Show (Labelled lab a)
instance (Read a) => Read (Labelled lab a)
instance (Bounded a) => Bounded (Labelled lab a)
instance (CoArbitrary a) => CoArbitrary (Labelled lab a)
instance (Arbitrary a) => Arbitrary (Labelled lab a)
instance (Monoid a) => Monoid (Labelled lab a)
instance (Knows lab (TypeOf lab) s) => Has lab s
instance (Contains (Labelled lab e) s) => Knows lab e s