Test.hs

{-# OPTIONS_GHC -fno-warn-redundant-constraints #-}
{-# LANGUAGE RankNTypes #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  Test
-- Copyright   :  (c) Simon Marlow 2002
-- License     :  BSD-style
--
-- Maintainer  :  libraries@haskell.org
-- Stability   :  provisional
-- Portability :  portable
--
-- This module illustrates & tests most of the features of Haddock.
-- Testing references from the description: 'T', 'f', 'g', 'Visible.visible'.
--
-----------------------------------------------------------------------------

-- This is plain comment, ignored by Haddock.

module Test (

        -- Section headings are introduced with '-- *':
        -- * Type declarations

        -- Subsection headings are introduced with '-- **' and so on.
        -- ** Data types
        T(..), T2, T3(..), T4(..), T5(..), T6(..),
        N1(..), N2(..), N3(..), N4, N5(..), N6(..), N7(..),

        -- ** Records
        R(..), R1(..),

        -- | test that we can export record selectors on their own:
        p, q, u,

        -- * Class declarations
        C(a,b), D(..), E, F(..),

        -- | Test that we can export a class method on its own:
        a,

        -- * Function types
        f, g,

        -- * Auxiliary stuff

        -- $aux1

        -- $aux2

        -- $aux3

        -- $aux4

        -- $aux5

        -- $aux6

        -- $aux7

        -- $aux8

        -- $aux9

        -- $aux10

        -- $aux11

        -- $aux12

        -- | This is some inline documentation in the export list
        --
        -- > a code block using bird-tracks
        -- > each line must begin with > (which isn't significant unless it
        -- > is at the beginning of the line).

        -- * A hidden module
        module Hidden,

        -- * A visible module
        module Visible,

        {-| nested-style doc comments -}

        -- * Existential \/ Universal types
        Ex(..),

        -- * Type signatures with argument docs
        k, l, m, o,

        -- * A section
        -- and without an intervening comma:
        -- ** A subsection

{-|
 > a literal line

 $ a non /literal/ line $
-}

        f',
   ) where

import Hidden
import Visible

-- | This comment applies to the /following/ declaration
-- and it continues until the next non-comment line
data T a b
 = A Int (Maybe Float) -- ^ This comment describes the 'A' constructor
 | -- | This comment describes the 'B' constructor
   B (T a b, T Int Float) -- ^

-- | An abstract data declaration
data T2 a b = T2 a b

-- | A data declaration with no documentation annotations on the constructors
data T3 a b = A1 a | B1 b

-- A data declaration with no documentation annotations at all
data T4 a b = A2 a | B2 b

-- A data declaration documentation on the constructors only
data T5 a b
  = A3 a -- ^ documents 'A3'
  | B3 b -- ^ documents 'B3'

-- | Testing alternative comment styles
data T6
  -- | This is the doc for 'A4'
  = A4
  | B4
  | -- ^ This is the doc for 'B4'

    -- | This is the doc for 'C4'
    C4

-- | A newtype
newtype N1 a = N1 a

-- | A newtype with a fieldname
newtype N2 a b = N2 {n :: a b}

-- | A newtype with a fieldname, documentation on the field
newtype N3 a b = N3 {n3 :: a b -- ^ this is the 'n3' field
                    }

-- | An abstract newtype - we show this one as data rather than newtype because
-- the difference isn\'t visible to the programmer for an abstract type.
newtype N4 a b = N4 a

newtype N5 a b = N5 {n5 :: a b -- ^ no docs on the datatype or the constructor
                    }

newtype N6 a b = N6 {n6 :: a b
                    }
                 -- ^ docs on the constructor only

-- | docs on the newtype and the constructor
newtype N7 a b = N7 {n7 :: a b
                    }
                -- ^ The 'N7' constructor


class (D a) => C a  where
   -- |this is a description of the 'a' method
   a :: IO a
   b :: [a]
   -- ^ this is a description of the 'b' method
   c :: a -- c is hidden in the export list

-- ^ This comment applies to the /previous/ declaration (the 'C' class)

class D a where
   d :: T a b
   e :: (a,a)
-- ^ This is a class declaration with no separate docs for the methods

instance D Int where
  d = undefined
  e = undefined

-- instance with a qualified class name
instance Test.D Float where
  d = undefined
  e = undefined

class E a where
  ee :: a
-- ^ This is a class declaration with no methods (or no methods exported)

-- This is a class declaration with no documentation at all
class F a where
  ff :: a

-- | This is the documentation for the 'R' record, which has four fields,
-- 'p', 'q', 'r', and 's'.
data R =
  -- | This is the 'C1' record constructor, with the following fields:
  C1 { p :: Int -- ^ This comment applies to the 'p' field
     , q :: forall a . a->a  -- ^ This comment applies to the 'q' field
     , -- | This comment applies to both 'r' and 's'
       r,s :: Int
     }
  | C2 { t :: T1 -> (T2 Int Int)-> (T3 Bool Bool) -> (T4 Float Float) -> T5 () (),
       u,v :: Int
     }
  -- ^ This is the 'C2' record constructor, also with some fields:

-- | Testing different record commenting styles
data R1
  -- | This is the 'C3' record constructor
  = C3 {
        -- | The 's1' record selector
          s1 :: Int
        -- | The 's2' record selector
        , s2 :: Int
        , s3 :: Int  -- NOTE: In the original examples/Test.hs in Haddock, there is an extra "," here.
                     -- Since GHC doesn't allow that, I have removed it in this file.
        -- ^ The 's3' record selector
     }

-- These section headers are only used when there is no export list to
-- give the structure of the documentation:

-- * This is a section header (level 1)
-- ** This is a section header (level 2)
-- *** This is a section header (level 3)

{-|
In a comment string we can refer to identifiers in scope with
single quotes like this: 'T', and we can refer to modules by
using double quotes: "Foo".  We can add emphasis /like this/.

   * This is a bulleted list

   - This is the next item (different kind of bullet)

   (1) This is an ordered list

   2. This is the next item (different kind of bullet)

@
     This is a block of code, which can include other markup: 'R'
     formatting
               is
                 significant
@

> this is another block of code

We can also include URLs in documentation: <http://www.haskell.org/>.
-}

f :: C a => a -> Int

-- | we can export foreign declarations too
foreign import ccall "header.h" g :: Int -> IO CInt

-- | this doc string has a parse error in it: \'
h :: Int
h = 42


-- $aux1 This is some documentation that is attached to a name ($aux1)
-- rather than a source declaration.  The documentation may be
-- referred to in the export list using its name.
--
-- @ code block in named doc @

-- $aux2 This is some documentation that is attached to a name ($aux2)

-- $aux3
-- @ code block on its own in named doc @

-- $aux4
--
-- @ code block on its own in named doc (after newline) @

{- $aux5 a nested, named doc comment

   with a paragraph,

   @ and a code block @
-}

-- some tests for various arrangements of code blocks:

{- $aux6
>test
>test1

@ test2
  test3
@
-}

{- $aux7
@
test1
test2
@
-}

{- $aux8
>test3
>test4
-}

{- $aux9
@
test1
test2
@

>test3
>test4
-}

{- $aux10
>test3
>test4

@
test1
test2
@
-}

-- This one is currently wrong (Haddock 0.4).  The @...@ part is
-- interpreted as part of the bird-tracked code block.
{- $aux11
aux11:

>test3
>test4

@
test1
test2
@
-}

-- $aux12
-- > foo
--
-- > bar
--

-- | A data-type using existential\/universal types
data Ex a
  = forall b . C b => Ex1 b
  | forall b . Ex2 b
  | forall b . C a => Ex3 b -- NOTE: I have added "forall b" here make GHC accept this file
  | Ex4 (forall a . a -> a)

-- | This is a function with documentation for each argument
k :: T () ()      -- ^ This argument has type 'T'
  -> (T2 Int Int) -- ^ This argument has type 'T2 Int Int'
  -> (T3 Bool Bool -> T4 Float Float) -- ^ This argument has type @T3 Bool Bool -> T4 Float Float@
  -> T5 () ()     -- ^ This argument has a very long description that should
                  -- hopefully cause some wrapping to happen when it is finally
                  -- rendered by Haddock in the generated HTML page.
  -> IO ()        -- ^ This is the result type

-- This function has arg docs but no docs for the function itself
l :: (Int, Int, Float) -- ^ takes a triple
  -> Int -- ^ returns an 'Int'

-- | This function has some arg docs
m :: R
  -> N1 ()      -- ^ one of the arguments
  -> IO Int     -- ^ and the return value

-- | This function has some arg docs but not a return value doc

-- can't use the original name ('n') with GHC
newn :: R               -- ^ one of the arguments, an 'R'
     -> N1 ()           -- ^ one of the arguments
     -> IO Int
newn = undefined


-- | A foreign import with argument docs
foreign import ccall unsafe "header.h"
 o :: Float  -- ^ The input float
   -> IO Float  -- ^ The output float

-- | We should be able to escape this: \#\#\#

-- p :: Int
-- can't use the above original definition with GHC
newp :: Int
newp = undefined

-- | a function with a prime can be referred to as 'f''
-- but f' doesn't get link'd 'f\''
f' :: Int


-- Add some definitions here so that this file can be compiled with GHC

data T1
f = undefined
f' = undefined
type CInt = Int
k = undefined
l = undefined
m = undefined