Copyright | (C) 2014-2016 Edward Kmett and Eric Mertens |
---|---|
License | BSD-style (see the file LICENSE) |
Maintainer | Edward Kmett <ekmett@gmail.com> |
Stability | experimental |
Portability | non-portable |
Safe Haskell | Trustworthy |
Language | Haskell2010 |
Synopsis
- makePrisms :: Name -> DecsQ
- makeClassyPrisms :: Name -> DecsQ
- makeDecPrisms :: Bool -> Dec -> DecsQ
Documentation
Generate a Prism
for each constructor of a data type.
Isos generated when possible.
Reviews are created for constructors with existentially
quantified constructors and GADTs.
e.g.
data FooBarBaz a = Foo Int | Bar a | Baz Int Char makePrisms ''FooBarBaz
will create
_Foo :: Prism' (FooBarBaz a) Int _Bar :: Prism (FooBarBaz a) (FooBarBaz b) a b _Baz :: Prism' (FooBarBaz a) (Int, Char)
Generate a Prism
for each constructor of a data type
and combine them into a single class. No Isos are created.
Reviews are created for constructors with existentially
quantified constructors and GADTs.
e.g.
data FooBarBaz a = Foo Int | Bar a | Baz Int Char makeClassyPrisms ''FooBarBaz
will create
class AsFooBarBaz s a | s -> a where _FooBarBaz :: Prism' s (FooBarBaz a) _Foo :: Prism' s Int _Bar :: Prism' s a _Baz :: Prism' s (Int,Char) _Foo = _FooBarBaz . _Foo _Bar = _FooBarBaz . _Bar _Baz = _FooBarBaz . _Baz instance AsFooBarBaz (FooBarBaz a) a
Generate an As class of prisms. Names are selected by prefixing the constructor name with an underscore. Constructors with multiple fields will construct Prisms to tuples of those fields.
In the event that the name of a data type is also the name of one of its
constructors, the name of the Prism
generated for the data type will be
prefixed with an extra _
(if the data type name is prefix) or .
(if the
name is infix) to disambiguate it from the Prism
for the corresponding
constructor. For example, this code:
data Quux = Quux Int | Fred Bool makeClassyPrisms ''Quux
will create:
class AsQuux s where __Quux :: Prism' s Quux -- Data type prism _Quux :: Prism' s Int -- Constructor prism _Fred :: Prism' s Bool _Quux = __Quux . _Quux _Fred = __Quux . _Fred instance AsQuux Quux