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


-- | A compiler for Fay, a Haskell subset that compiles to JavaScript.
--   
--   Fay is a proper subset of Haskell which is type-checked with GHC, and
--   compiled to JavaScript. It is lazy, pure, has a Fay monad, an FFI,
--   tail-recursion optimization (experimental), and support for cabal
--   packages.
--   
--   <i>Documentation</i>
--   
--   See <a>https://github.com/faylang/fay/wiki</a>
--   
--   <i>Examples</i>
--   
--   See the examples directory and
--   <a>https://github.com/faylang/fay/wiki#fay-in-the-wild</a>
@package fay
@version 0.24.0.1

module Fay.Compiler.Parse

-- | Parse some Fay code.
parseFay :: Parseable ast => FilePath -> String -> ParseResult ast
defaultExtensions :: [Extension]


-- | Re-exports of base functionality. Note that this module is just used
--   inside the compiler. It's not compiled to JavaScript. Based on the
--   base-extended package (c) 2013 Simon Meier, licensed as BSD3.
module Fay.Compiler.Prelude

-- | Append two lists, i.e.,
--   
--   <pre>
--   [x1, ..., xm] ++ [y1, ..., yn] == [x1, ..., xm, y1, ..., yn]
--   [x1, ..., xm] ++ [y1, ...] == [x1, ..., xm, y1, ...]
--   </pre>
--   
--   If the first list is not finite, the result is the first list.
(++) :: () => [a] -> [a] -> [a]
infixr 5 ++

-- | The value of <tt>seq a b</tt> is bottom if <tt>a</tt> is bottom, and
--   otherwise equal to <tt>b</tt>. In other words, it evaluates the first
--   argument <tt>a</tt> to weak head normal form (WHNF). <tt>seq</tt> is
--   usually introduced to improve performance by avoiding unneeded
--   laziness.
--   
--   A note on evaluation order: the expression <tt>seq a b</tt> does
--   <i>not</i> guarantee that <tt>a</tt> will be evaluated before
--   <tt>b</tt>. The only guarantee given by <tt>seq</tt> is that the both
--   <tt>a</tt> and <tt>b</tt> will be evaluated before <tt>seq</tt>
--   returns a value. In particular, this means that <tt>b</tt> may be
--   evaluated before <tt>a</tt>. If you need to guarantee a specific order
--   of evaluation, you must use the function <tt>pseq</tt> from the
--   "parallel" package.
seq :: () => a -> b -> b

-- | <a>filter</a>, applied to a predicate and a list, returns the list of
--   those elements that satisfy the predicate; i.e.,
--   
--   <pre>
--   filter p xs = [ x | x &lt;- xs, p x]
--   </pre>
filter :: () => a -> Bool -> [a] -> [a]

-- | <a>zip</a> takes two lists and returns a list of corresponding pairs.
--   If one input list is short, excess elements of the longer list are
--   discarded.
--   
--   <a>zip</a> is right-lazy:
--   
--   <pre>
--   zip [] _|_ = []
--   </pre>
zip :: () => [a] -> [b] -> [(a, b)]

-- | The <a>print</a> function outputs a value of any printable type to the
--   standard output device. Printable types are those that are instances
--   of class <a>Show</a>; <a>print</a> converts values to strings for
--   output using the <a>show</a> operation and adds a newline.
--   
--   For example, a program to print the first 20 integers and their powers
--   of 2 could be written as:
--   
--   <pre>
--   main = print ([(n, 2^n) | n &lt;- [0..19]])
--   </pre>
print :: Show a => a -> IO ()

-- | Extract the first component of a pair.
fst :: () => (a, b) -> a

-- | Extract the second component of a pair.
snd :: () => (a, b) -> b

-- | <a>otherwise</a> is defined as the value <a>True</a>. It helps to make
--   guards more readable. eg.
--   
--   <pre>
--   f x | x &lt; 0     = ...
--       | otherwise = ...
--   </pre>
otherwise :: Bool

-- | <a>map</a> <tt>f xs</tt> is the list obtained by applying <tt>f</tt>
--   to each element of <tt>xs</tt>, i.e.,
--   
--   <pre>
--   map f [x1, x2, ..., xn] == [f x1, f x2, ..., f xn]
--   map f [x1, x2, ...] == [f x1, f x2, ...]
--   </pre>
map :: () => a -> b -> [a] -> [b]

-- | Application operator. This operator is redundant, since ordinary
--   application <tt>(f x)</tt> means the same as <tt>(f <a>$</a> x)</tt>.
--   However, <a>$</a> has low, right-associative binding precedence, so it
--   sometimes allows parentheses to be omitted; for example:
--   
--   <pre>
--   f $ g $ h x  =  f (g (h x))
--   </pre>
--   
--   It is also useful in higher-order situations, such as <tt><a>map</a>
--   (<a>$</a> 0) xs</tt>, or <tt><a>zipWith</a> (<a>$</a>) fs xs</tt>.
($) :: () => a -> b -> a -> b
infixr 0 $

-- | general coercion from integral types
fromIntegral :: (Integral a, Num b) => a -> b

-- | general coercion to fractional types
realToFrac :: (Real a, Fractional b) => a -> b

-- | The <a>Bounded</a> class is used to name the upper and lower limits of
--   a type. <a>Ord</a> is not a superclass of <a>Bounded</a> since types
--   that are not totally ordered may also have upper and lower bounds.
--   
--   The <a>Bounded</a> class may be derived for any enumeration type;
--   <a>minBound</a> is the first constructor listed in the <tt>data</tt>
--   declaration and <a>maxBound</a> is the last. <a>Bounded</a> may also
--   be derived for single-constructor datatypes whose constituent types
--   are in <a>Bounded</a>.
class Bounded a
minBound :: Bounded a => a
maxBound :: Bounded a => a

-- | Class <a>Enum</a> defines operations on sequentially ordered types.
--   
--   The <tt>enumFrom</tt>... methods are used in Haskell's translation of
--   arithmetic sequences.
--   
--   Instances of <a>Enum</a> may be derived for any enumeration type
--   (types whose constructors have no fields). The nullary constructors
--   are assumed to be numbered left-to-right by <a>fromEnum</a> from
--   <tt>0</tt> through <tt>n-1</tt>. See Chapter 10 of the <i>Haskell
--   Report</i> for more details.
--   
--   For any type that is an instance of class <a>Bounded</a> as well as
--   <a>Enum</a>, the following should hold:
--   
--   <ul>
--   <li>The calls <tt><a>succ</a> <a>maxBound</a></tt> and <tt><a>pred</a>
--   <a>minBound</a></tt> should result in a runtime error.</li>
--   <li><a>fromEnum</a> and <a>toEnum</a> should give a runtime error if
--   the result value is not representable in the result type. For example,
--   <tt><a>toEnum</a> 7 :: <a>Bool</a></tt> is an error.</li>
--   <li><a>enumFrom</a> and <a>enumFromThen</a> should be defined with an
--   implicit bound, thus:</li>
--   </ul>
--   
--   <pre>
--   enumFrom     x   = enumFromTo     x maxBound
--   enumFromThen x y = enumFromThenTo x y bound
--     where
--       bound | fromEnum y &gt;= fromEnum x = maxBound
--             | otherwise                = minBound
--   </pre>
class Enum a

-- | the successor of a value. For numeric types, <a>succ</a> adds 1.
succ :: Enum a => a -> a

-- | the predecessor of a value. For numeric types, <a>pred</a> subtracts
--   1.
pred :: Enum a => a -> a

-- | Convert from an <a>Int</a>.
toEnum :: Enum a => Int -> a

-- | Convert to an <a>Int</a>. It is implementation-dependent what
--   <a>fromEnum</a> returns when applied to a value that is too large to
--   fit in an <a>Int</a>.
fromEnum :: Enum a => a -> Int

-- | Used in Haskell's translation of <tt>[n..]</tt>.
enumFrom :: Enum a => a -> [a]

-- | Used in Haskell's translation of <tt>[n,n'..]</tt>.
enumFromThen :: Enum a => a -> a -> [a]

-- | Used in Haskell's translation of <tt>[n..m]</tt>.
enumFromTo :: Enum a => a -> a -> [a]

-- | Used in Haskell's translation of <tt>[n,n'..m]</tt>.
enumFromThenTo :: Enum a => a -> a -> a -> [a]

-- | The <a>Eq</a> class defines equality (<a>==</a>) and inequality
--   (<a>/=</a>). All the basic datatypes exported by the <a>Prelude</a>
--   are instances of <a>Eq</a>, and <a>Eq</a> may be derived for any
--   datatype whose constituents are also instances of <a>Eq</a>.
--   
--   Minimal complete definition: either <a>==</a> or <a>/=</a>.
class Eq a
(==) :: Eq a => a -> a -> Bool
(/=) :: Eq a => a -> a -> Bool

-- | Trigonometric and hyperbolic functions and related functions.
class Fractional a => Floating a
pi :: Floating a => a
log :: Floating a => a -> a
sqrt :: Floating a => a -> a
(**) :: Floating a => a -> a -> a
logBase :: Floating a => a -> a -> a
sin :: Floating a => a -> a
cos :: Floating a => a -> a
tan :: Floating a => a -> a
asin :: Floating a => a -> a
acos :: Floating a => a -> a
atan :: Floating a => a -> a
sinh :: Floating a => a -> a
cosh :: Floating a => a -> a
tanh :: Floating a => a -> a
asinh :: Floating a => a -> a
acosh :: Floating a => a -> a
atanh :: Floating a => a -> a

-- | Fractional numbers, supporting real division.
class Num a => Fractional a

-- | fractional division
(/) :: Fractional a => a -> a -> a

-- | reciprocal fraction
recip :: Fractional a => a -> a

-- | Conversion from a <a>Rational</a> (that is <tt><a>Ratio</a>
--   <a>Integer</a></tt>). A floating literal stands for an application of
--   <a>fromRational</a> to a value of type <a>Rational</a>, so such
--   literals have type <tt>(<a>Fractional</a> a) =&gt; a</tt>.
fromRational :: Fractional a => Rational -> a

-- | Integral numbers, supporting integer division.
class (Real a, Enum a) => Integral a

-- | integer division truncated toward zero
quot :: Integral a => a -> a -> a

-- | integer remainder, satisfying
--   
--   <pre>
--   (x `quot` y)*y + (x `rem` y) == x
--   </pre>
rem :: Integral a => a -> a -> a

-- | integer division truncated toward negative infinity
div :: Integral a => a -> a -> a

-- | simultaneous <a>quot</a> and <a>rem</a>
quotRem :: Integral a => a -> a -> (a, a)

-- | simultaneous <a>div</a> and <a>mod</a>
divMod :: Integral a => a -> a -> (a, a)

-- | conversion to <a>Integer</a>
toInteger :: Integral a => a -> Integer

-- | The <a>Monad</a> class defines the basic operations over a
--   <i>monad</i>, a concept from a branch of mathematics known as
--   <i>category theory</i>. From the perspective of a Haskell programmer,
--   however, it is best to think of a monad as an <i>abstract datatype</i>
--   of actions. Haskell's <tt>do</tt> expressions provide a convenient
--   syntax for writing monadic expressions.
--   
--   Instances of <a>Monad</a> should satisfy the following laws:
--   
--   <ul>
--   <li><pre><a>return</a> a <a>&gt;&gt;=</a> k = k a</pre></li>
--   <li><pre>m <a>&gt;&gt;=</a> <a>return</a> = m</pre></li>
--   <li><pre>m <a>&gt;&gt;=</a> (\x -&gt; k x <a>&gt;&gt;=</a> h) = (m
--   <a>&gt;&gt;=</a> k) <a>&gt;&gt;=</a> h</pre></li>
--   </ul>
--   
--   Furthermore, the <a>Monad</a> and <a>Applicative</a> operations should
--   relate as follows:
--   
--   <ul>
--   <li><pre><a>pure</a> = <a>return</a></pre></li>
--   <li><pre>(<a>&lt;*&gt;</a>) = <a>ap</a></pre></li>
--   </ul>
--   
--   The above laws imply:
--   
--   <ul>
--   <li><pre><a>fmap</a> f xs = xs <a>&gt;&gt;=</a> <a>return</a> .
--   f</pre></li>
--   <li><pre>(<a>&gt;&gt;</a>) = (<a>*&gt;</a>)</pre></li>
--   </ul>
--   
--   and that <a>pure</a> and (<a>&lt;*&gt;</a>) satisfy the applicative
--   functor laws.
--   
--   The instances of <a>Monad</a> for lists, <a>Maybe</a> and <a>IO</a>
--   defined in the <a>Prelude</a> satisfy these laws.
class Applicative m => Monad (m :: * -> *)

-- | Sequentially compose two actions, passing any value produced by the
--   first as an argument to the second.
(>>=) :: Monad m => m a -> a -> m b -> m b

-- | Sequentially compose two actions, discarding any value produced by the
--   first, like sequencing operators (such as the semicolon) in imperative
--   languages.
(>>) :: Monad m => m a -> m b -> m b

-- | Inject a value into the monadic type.
return :: Monad m => a -> m a

-- | Fail with a message. This operation is not part of the mathematical
--   definition of a monad, but is invoked on pattern-match failure in a
--   <tt>do</tt> expression.
--   
--   As part of the MonadFail proposal (MFP), this function is moved to its
--   own class <tt>MonadFail</tt> (see <a>Control.Monad.Fail</a> for more
--   details). The definition here will be removed in a future release.
fail :: Monad m => String -> m a

-- | The <a>Functor</a> class is used for types that can be mapped over.
--   Instances of <a>Functor</a> should satisfy the following laws:
--   
--   <pre>
--   fmap id  ==  id
--   fmap (f . g)  ==  fmap f . fmap g
--   </pre>
--   
--   The instances of <a>Functor</a> for lists, <a>Maybe</a> and <a>IO</a>
--   satisfy these laws.
class Functor (f :: * -> *)
fmap :: Functor f => a -> b -> f a -> f b

-- | Replace all locations in the input with the same value. The default
--   definition is <tt><a>fmap</a> . <a>const</a></tt>, but this may be
--   overridden with a more efficient version.
(<$) :: Functor f => a -> f b -> f a

-- | Basic numeric class.
class Num a
(+) :: Num a => a -> a -> a
(-) :: Num a => a -> a -> a
(*) :: Num a => a -> a -> a

-- | Unary negation.
negate :: Num a => a -> a

-- | Absolute value.
abs :: Num a => a -> a

-- | Sign of a number. The functions <a>abs</a> and <a>signum</a> should
--   satisfy the law:
--   
--   <pre>
--   abs x * signum x == x
--   </pre>
--   
--   For real numbers, the <a>signum</a> is either <tt>-1</tt> (negative),
--   <tt>0</tt> (zero) or <tt>1</tt> (positive).
signum :: Num a => a -> a

-- | Conversion from an <a>Integer</a>. An integer literal represents the
--   application of the function <a>fromInteger</a> to the appropriate
--   value of type <a>Integer</a>, so such literals have type
--   <tt>(<a>Num</a> a) =&gt; a</tt>.
fromInteger :: Num a => Integer -> a

-- | The <a>Ord</a> class is used for totally ordered datatypes.
--   
--   Instances of <a>Ord</a> can be derived for any user-defined datatype
--   whose constituent types are in <a>Ord</a>. The declared order of the
--   constructors in the data declaration determines the ordering in
--   derived <a>Ord</a> instances. The <a>Ordering</a> datatype allows a
--   single comparison to determine the precise ordering of two objects.
--   
--   Minimal complete definition: either <a>compare</a> or <a>&lt;=</a>.
--   Using <a>compare</a> can be more efficient for complex types.
class Eq a => Ord a
compare :: Ord a => a -> a -> Ordering
(<) :: Ord a => a -> a -> Bool
(<=) :: Ord a => a -> a -> Bool
(>) :: Ord a => a -> a -> Bool
(>=) :: Ord a => a -> a -> Bool
max :: Ord a => a -> a -> a
min :: Ord a => a -> a -> a

-- | Parsing of <a>String</a>s, producing values.
--   
--   Derived instances of <a>Read</a> make the following assumptions, which
--   derived instances of <a>Show</a> obey:
--   
--   <ul>
--   <li>If the constructor is defined to be an infix operator, then the
--   derived <a>Read</a> instance will parse only infix applications of the
--   constructor (not the prefix form).</li>
--   <li>Associativity is not used to reduce the occurrence of parentheses,
--   although precedence may be.</li>
--   <li>If the constructor is defined using record syntax, the derived
--   <a>Read</a> will parse only the record-syntax form, and furthermore,
--   the fields must be given in the same order as the original
--   declaration.</li>
--   <li>The derived <a>Read</a> instance allows arbitrary Haskell
--   whitespace between tokens of the input string. Extra parentheses are
--   also allowed.</li>
--   </ul>
--   
--   For example, given the declarations
--   
--   <pre>
--   infixr 5 :^:
--   data Tree a =  Leaf a  |  Tree a :^: Tree a
--   </pre>
--   
--   the derived instance of <a>Read</a> in Haskell 2010 is equivalent to
--   
--   <pre>
--   instance (Read a) =&gt; Read (Tree a) where
--   
--           readsPrec d r =  readParen (d &gt; app_prec)
--                            (\r -&gt; [(Leaf m,t) |
--                                    ("Leaf",s) &lt;- lex r,
--                                    (m,t) &lt;- readsPrec (app_prec+1) s]) r
--   
--                         ++ readParen (d &gt; up_prec)
--                            (\r -&gt; [(u:^:v,w) |
--                                    (u,s) &lt;- readsPrec (up_prec+1) r,
--                                    (":^:",t) &lt;- lex s,
--                                    (v,w) &lt;- readsPrec (up_prec+1) t]) r
--   
--             where app_prec = 10
--                   up_prec = 5
--   </pre>
--   
--   Note that right-associativity of <tt>:^:</tt> is unused.
--   
--   The derived instance in GHC is equivalent to
--   
--   <pre>
--   instance (Read a) =&gt; Read (Tree a) where
--   
--           readPrec = parens $ (prec app_prec $ do
--                                    Ident "Leaf" &lt;- lexP
--                                    m &lt;- step readPrec
--                                    return (Leaf m))
--   
--                        +++ (prec up_prec $ do
--                                    u &lt;- step readPrec
--                                    Symbol ":^:" &lt;- lexP
--                                    v &lt;- step readPrec
--                                    return (u :^: v))
--   
--             where app_prec = 10
--                   up_prec = 5
--   
--           readListPrec = readListPrecDefault
--   </pre>
--   
--   Why do both <a>readsPrec</a> and <a>readPrec</a> exist, and why does
--   GHC opt to implement <a>readPrec</a> in derived <a>Read</a> instances
--   instead of <a>readsPrec</a>? The reason is that <a>readsPrec</a> is
--   based on the <a>ReadS</a> type, and although <a>ReadS</a> is mentioned
--   in the Haskell 2010 Report, it is not a very efficient parser data
--   structure.
--   
--   <a>readPrec</a>, on the other hand, is based on a much more efficient
--   <a>ReadPrec</a> datatype (a.k.a "new-style parsers"), but its
--   definition relies on the use of the <tt>RankNTypes</tt> language
--   extension. Therefore, <a>readPrec</a> (and its cousin,
--   <a>readListPrec</a>) are marked as GHC-only. Nevertheless, it is
--   recommended to use <a>readPrec</a> instead of <a>readsPrec</a>
--   whenever possible for the efficiency improvements it brings.
--   
--   As mentioned above, derived <a>Read</a> instances in GHC will
--   implement <a>readPrec</a> instead of <a>readsPrec</a>. The default
--   implementations of <a>readsPrec</a> (and its cousin, <a>readList</a>)
--   will simply use <a>readPrec</a> under the hood. If you are writing a
--   <a>Read</a> instance by hand, it is recommended to write it like so:
--   
--   <pre>
--   instance <a>Read</a> T where
--     <a>readPrec</a>     = ...
--     <a>readListPrec</a> = <a>readListPrecDefault</a>
--   </pre>
class Read a

-- | attempts to parse a value from the front of the string, returning a
--   list of (parsed value, remaining string) pairs. If there is no
--   successful parse, the returned list is empty.
--   
--   Derived instances of <a>Read</a> and <a>Show</a> satisfy the
--   following:
--   
--   <ul>
--   <li><tt>(x,"")</tt> is an element of <tt>(<a>readsPrec</a> d
--   (<a>showsPrec</a> d x ""))</tt>.</li>
--   </ul>
--   
--   That is, <a>readsPrec</a> parses the string produced by
--   <a>showsPrec</a>, and delivers the value that <a>showsPrec</a> started
--   with.
readsPrec :: Read a => Int -> ReadS a

-- | The method <a>readList</a> is provided to allow the programmer to give
--   a specialised way of parsing lists of values. For example, this is
--   used by the predefined <a>Read</a> instance of the <a>Char</a> type,
--   where values of type <a>String</a> should be are expected to use
--   double quotes, rather than square brackets.
readList :: Read a => ReadS [a]
class (Num a, Ord a) => Real a

-- | the rational equivalent of its real argument with full precision
toRational :: Real a => a -> Rational

-- | Efficient, machine-independent access to the components of a
--   floating-point number.
class (RealFrac a, Floating a) => RealFloat a

-- | a constant function, returning the radix of the representation (often
--   <tt>2</tt>)
floatRadix :: RealFloat a => a -> Integer

-- | a constant function, returning the number of digits of
--   <a>floatRadix</a> in the significand
floatDigits :: RealFloat a => a -> Int

-- | a constant function, returning the lowest and highest values the
--   exponent may assume
floatRange :: RealFloat a => a -> (Int, Int)

-- | The function <a>decodeFloat</a> applied to a real floating-point
--   number returns the significand expressed as an <a>Integer</a> and an
--   appropriately scaled exponent (an <a>Int</a>). If
--   <tt><a>decodeFloat</a> x</tt> yields <tt>(m,n)</tt>, then <tt>x</tt>
--   is equal in value to <tt>m*b^^n</tt>, where <tt>b</tt> is the
--   floating-point radix, and furthermore, either <tt>m</tt> and
--   <tt>n</tt> are both zero or else <tt>b^(d-1) &lt;= <a>abs</a> m &lt;
--   b^d</tt>, where <tt>d</tt> is the value of <tt><a>floatDigits</a>
--   x</tt>. In particular, <tt><a>decodeFloat</a> 0 = (0,0)</tt>. If the
--   type contains a negative zero, also <tt><a>decodeFloat</a> (-0.0) =
--   (0,0)</tt>. <i>The result of</i> <tt><a>decodeFloat</a> x</tt> <i>is
--   unspecified if either of</i> <tt><a>isNaN</a> x</tt> <i>or</i>
--   <tt><a>isInfinite</a> x</tt> <i>is</i> <a>True</a>.
decodeFloat :: RealFloat a => a -> (Integer, Int)

-- | <a>encodeFloat</a> performs the inverse of <a>decodeFloat</a> in the
--   sense that for finite <tt>x</tt> with the exception of <tt>-0.0</tt>,
--   <tt><tt>uncurry</tt> <a>encodeFloat</a> (<a>decodeFloat</a> x) =
--   x</tt>. <tt><a>encodeFloat</a> m n</tt> is one of the two closest
--   representable floating-point numbers to <tt>m*b^^n</tt> (or
--   <tt>±Infinity</tt> if overflow occurs); usually the closer, but if
--   <tt>m</tt> contains too many bits, the result may be rounded in the
--   wrong direction.
encodeFloat :: RealFloat a => Integer -> Int -> a

-- | <a>exponent</a> corresponds to the second component of
--   <a>decodeFloat</a>. <tt><a>exponent</a> 0 = 0</tt> and for finite
--   nonzero <tt>x</tt>, <tt><a>exponent</a> x = snd (<a>decodeFloat</a> x)
--   + <a>floatDigits</a> x</tt>. If <tt>x</tt> is a finite floating-point
--   number, it is equal in value to <tt><a>significand</a> x * b ^^
--   <a>exponent</a> x</tt>, where <tt>b</tt> is the floating-point radix.
--   The behaviour is unspecified on infinite or <tt>NaN</tt> values.
exponent :: RealFloat a => a -> Int

-- | The first component of <a>decodeFloat</a>, scaled to lie in the open
--   interval (<tt>-1</tt>,<tt>1</tt>), either <tt>0.0</tt> or of absolute
--   value <tt>&gt;= 1/b</tt>, where <tt>b</tt> is the floating-point
--   radix. The behaviour is unspecified on infinite or <tt>NaN</tt>
--   values.
significand :: RealFloat a => a -> a

-- | multiplies a floating-point number by an integer power of the radix
scaleFloat :: RealFloat a => Int -> a -> a

-- | <a>True</a> if the argument is an IEEE "not-a-number" (NaN) value
isNaN :: RealFloat a => a -> Bool

-- | <a>True</a> if the argument is an IEEE infinity or negative infinity
isInfinite :: RealFloat a => a -> Bool

-- | <a>True</a> if the argument is too small to be represented in
--   normalized format
isDenormalized :: RealFloat a => a -> Bool

-- | <a>True</a> if the argument is an IEEE negative zero
isNegativeZero :: RealFloat a => a -> Bool

-- | <a>True</a> if the argument is an IEEE floating point number
isIEEE :: RealFloat a => a -> Bool

-- | a version of arctangent taking two real floating-point arguments. For
--   real floating <tt>x</tt> and <tt>y</tt>, <tt><a>atan2</a> y x</tt>
--   computes the angle (from the positive x-axis) of the vector from the
--   origin to the point <tt>(x,y)</tt>. <tt><a>atan2</a> y x</tt> returns
--   a value in the range [<tt>-pi</tt>, <tt>pi</tt>]. It follows the
--   Common Lisp semantics for the origin when signed zeroes are supported.
--   <tt><a>atan2</a> y 1</tt>, with <tt>y</tt> in a type that is
--   <a>RealFloat</a>, should return the same value as <tt><a>atan</a>
--   y</tt>. A default definition of <a>atan2</a> is provided, but
--   implementors can provide a more accurate implementation.
atan2 :: RealFloat a => a -> a -> a

-- | Extracting components of fractions.
class (Real a, Fractional a) => RealFrac a

-- | The function <a>properFraction</a> takes a real fractional number
--   <tt>x</tt> and returns a pair <tt>(n,f)</tt> such that <tt>x =
--   n+f</tt>, and:
--   
--   <ul>
--   <li><tt>n</tt> is an integral number with the same sign as <tt>x</tt>;
--   and</li>
--   <li><tt>f</tt> is a fraction with the same type and sign as
--   <tt>x</tt>, and with absolute value less than <tt>1</tt>.</li>
--   </ul>
--   
--   The default definitions of the <a>ceiling</a>, <a>floor</a>,
--   <a>truncate</a> and <a>round</a> functions are in terms of
--   <a>properFraction</a>.
properFraction :: (RealFrac a, Integral b) => a -> (b, a)

-- | <tt><a>truncate</a> x</tt> returns the integer nearest <tt>x</tt>
--   between zero and <tt>x</tt>
truncate :: (RealFrac a, Integral b) => a -> b

-- | <tt><a>round</a> x</tt> returns the nearest integer to <tt>x</tt>; the
--   even integer if <tt>x</tt> is equidistant between two integers
round :: (RealFrac a, Integral b) => a -> b

-- | <tt><a>ceiling</a> x</tt> returns the least integer not less than
--   <tt>x</tt>
ceiling :: (RealFrac a, Integral b) => a -> b

-- | <tt><a>floor</a> x</tt> returns the greatest integer not greater than
--   <tt>x</tt>
floor :: (RealFrac a, Integral b) => a -> b

-- | Conversion of values to readable <a>String</a>s.
--   
--   Derived instances of <a>Show</a> have the following properties, which
--   are compatible with derived instances of <a>Read</a>:
--   
--   <ul>
--   <li>The result of <a>show</a> is a syntactically correct Haskell
--   expression containing only constants, given the fixity declarations in
--   force at the point where the type is declared. It contains only the
--   constructor names defined in the data type, parentheses, and spaces.
--   When labelled constructor fields are used, braces, commas, field
--   names, and equal signs are also used.</li>
--   <li>If the constructor is defined to be an infix operator, then
--   <a>showsPrec</a> will produce infix applications of the
--   constructor.</li>
--   <li>the representation will be enclosed in parentheses if the
--   precedence of the top-level constructor in <tt>x</tt> is less than
--   <tt>d</tt> (associativity is ignored). Thus, if <tt>d</tt> is
--   <tt>0</tt> then the result is never surrounded in parentheses; if
--   <tt>d</tt> is <tt>11</tt> it is always surrounded in parentheses,
--   unless it is an atomic expression.</li>
--   <li>If the constructor is defined using record syntax, then
--   <a>show</a> will produce the record-syntax form, with the fields given
--   in the same order as the original declaration.</li>
--   </ul>
--   
--   For example, given the declarations
--   
--   <pre>
--   infixr 5 :^:
--   data Tree a =  Leaf a  |  Tree a :^: Tree a
--   </pre>
--   
--   the derived instance of <a>Show</a> is equivalent to
--   
--   <pre>
--   instance (Show a) =&gt; Show (Tree a) where
--   
--          showsPrec d (Leaf m) = showParen (d &gt; app_prec) $
--               showString "Leaf " . showsPrec (app_prec+1) m
--            where app_prec = 10
--   
--          showsPrec d (u :^: v) = showParen (d &gt; up_prec) $
--               showsPrec (up_prec+1) u .
--               showString " :^: "      .
--               showsPrec (up_prec+1) v
--            where up_prec = 5
--   </pre>
--   
--   Note that right-associativity of <tt>:^:</tt> is ignored. For example,
--   
--   <ul>
--   <li><tt><a>show</a> (Leaf 1 :^: Leaf 2 :^: Leaf 3)</tt> produces the
--   string <tt>"Leaf 1 :^: (Leaf 2 :^: Leaf 3)"</tt>.</li>
--   </ul>
class Show a

-- | Convert a value to a readable <a>String</a>.
--   
--   <a>showsPrec</a> should satisfy the law
--   
--   <pre>
--   showsPrec d x r ++ s  ==  showsPrec d x (r ++ s)
--   </pre>
--   
--   Derived instances of <a>Read</a> and <a>Show</a> satisfy the
--   following:
--   
--   <ul>
--   <li><tt>(x,"")</tt> is an element of <tt>(<a>readsPrec</a> d
--   (<a>showsPrec</a> d x ""))</tt>.</li>
--   </ul>
--   
--   That is, <a>readsPrec</a> parses the string produced by
--   <a>showsPrec</a>, and delivers the value that <a>showsPrec</a> started
--   with.
showsPrec :: Show a => Int -> a -> ShowS

-- | A specialised variant of <a>showsPrec</a>, using precedence context
--   zero, and returning an ordinary <a>String</a>.
show :: Show a => a -> String

-- | The method <a>showList</a> is provided to allow the programmer to give
--   a specialised way of showing lists of values. For example, this is
--   used by the predefined <a>Show</a> instance of the <a>Char</a> type,
--   where values of type <a>String</a> should be shown in double quotes,
--   rather than between square brackets.
showList :: Show a => [a] -> ShowS

-- | A functor with application, providing operations to
--   
--   <ul>
--   <li>embed pure expressions (<a>pure</a>), and</li>
--   <li>sequence computations and combine their results (<a>&lt;*&gt;</a>
--   and <a>liftA2</a>).</li>
--   </ul>
--   
--   A minimal complete definition must include implementations of
--   <a>pure</a> and of either <a>&lt;*&gt;</a> or <a>liftA2</a>. If it
--   defines both, then they must behave the same as their default
--   definitions:
--   
--   <pre>
--   (<a>&lt;*&gt;</a>) = <a>liftA2</a> <a>id</a>
--   </pre>
--   
--   <pre>
--   <a>liftA2</a> f x y = f <tt>&lt;$&gt;</tt> x <a>&lt;*&gt;</a> y
--   </pre>
--   
--   Further, any definition must satisfy the following:
--   
--   <ul>
--   <li><i><i>identity</i></i> <pre><a>pure</a> <a>id</a> <a>&lt;*&gt;</a>
--   v = v</pre></li>
--   <li><i><i>composition</i></i> <pre><a>pure</a> (.) <a>&lt;*&gt;</a> u
--   <a>&lt;*&gt;</a> v <a>&lt;*&gt;</a> w = u <a>&lt;*&gt;</a> (v
--   <a>&lt;*&gt;</a> w)</pre></li>
--   <li><i><i>homomorphism</i></i> <pre><a>pure</a> f <a>&lt;*&gt;</a>
--   <a>pure</a> x = <a>pure</a> (f x)</pre></li>
--   <li><i><i>interchange</i></i> <pre>u <a>&lt;*&gt;</a> <a>pure</a> y =
--   <a>pure</a> (<a>$</a> y) <a>&lt;*&gt;</a> u</pre></li>
--   </ul>
--   
--   The other methods have the following default definitions, which may be
--   overridden with equivalent specialized implementations:
--   
--   <ul>
--   <li><pre>u <a>*&gt;</a> v = (<a>id</a> <a>&lt;$</a> u)
--   <a>&lt;*&gt;</a> v</pre></li>
--   <li><pre>u <a>&lt;*</a> v = <a>liftA2</a> <a>const</a> u v</pre></li>
--   </ul>
--   
--   As a consequence of these laws, the <a>Functor</a> instance for
--   <tt>f</tt> will satisfy
--   
--   <ul>
--   <li><pre><a>fmap</a> f x = <a>pure</a> f <a>&lt;*&gt;</a> x</pre></li>
--   </ul>
--   
--   It may be useful to note that supposing
--   
--   <pre>
--   forall x y. p (q x y) = f x . g y
--   </pre>
--   
--   it follows from the above that
--   
--   <pre>
--   <a>liftA2</a> p (<a>liftA2</a> q u v) = <a>liftA2</a> f u . <a>liftA2</a> g v
--   </pre>
--   
--   If <tt>f</tt> is also a <a>Monad</a>, it should satisfy
--   
--   <ul>
--   <li><pre><a>pure</a> = <a>return</a></pre></li>
--   <li><pre>(<a>&lt;*&gt;</a>) = <a>ap</a></pre></li>
--   <li><pre>(<a>*&gt;</a>) = (<a>&gt;&gt;</a>)</pre></li>
--   </ul>
--   
--   (which implies that <a>pure</a> and <a>&lt;*&gt;</a> satisfy the
--   applicative functor laws).
class Functor f => Applicative (f :: * -> *)

-- | Lift a value.
pure :: Applicative f => a -> f a

-- | Sequential application.
--   
--   A few functors support an implementation of <a>&lt;*&gt;</a> that is
--   more efficient than the default one.
(<*>) :: Applicative f => f a -> b -> f a -> f b

-- | Sequence actions, discarding the value of the first argument.
(*>) :: Applicative f => f a -> f b -> f b

-- | Sequence actions, discarding the value of the second argument.
(<*) :: Applicative f => f a -> f b -> f a

-- | Data structures that can be folded.
--   
--   For example, given a data type
--   
--   <pre>
--   data Tree a = Empty | Leaf a | Node (Tree a) a (Tree a)
--   </pre>
--   
--   a suitable instance would be
--   
--   <pre>
--   instance Foldable Tree where
--      foldMap f Empty = mempty
--      foldMap f (Leaf x) = f x
--      foldMap f (Node l k r) = foldMap f l `mappend` f k `mappend` foldMap f r
--   </pre>
--   
--   This is suitable even for abstract types, as the monoid is assumed to
--   satisfy the monoid laws. Alternatively, one could define
--   <tt>foldr</tt>:
--   
--   <pre>
--   instance Foldable Tree where
--      foldr f z Empty = z
--      foldr f z (Leaf x) = f x z
--      foldr f z (Node l k r) = foldr f (f k (foldr f z r)) l
--   </pre>
--   
--   <tt>Foldable</tt> instances are expected to satisfy the following
--   laws:
--   
--   <pre>
--   foldr f z t = appEndo (foldMap (Endo . f) t ) z
--   </pre>
--   
--   <pre>
--   foldl f z t = appEndo (getDual (foldMap (Dual . Endo . flip f) t)) z
--   </pre>
--   
--   <pre>
--   fold = foldMap id
--   </pre>
--   
--   <pre>
--   length = getSum . foldMap (Sum . const  1)
--   </pre>
--   
--   <tt>sum</tt>, <tt>product</tt>, <tt>maximum</tt>, and <tt>minimum</tt>
--   should all be essentially equivalent to <tt>foldMap</tt> forms, such
--   as
--   
--   <pre>
--   sum = getSum . foldMap Sum
--   </pre>
--   
--   but may be less defined.
--   
--   If the type is also a <a>Functor</a> instance, it should satisfy
--   
--   <pre>
--   foldMap f = fold . fmap f
--   </pre>
--   
--   which implies that
--   
--   <pre>
--   foldMap f . fmap g = foldMap (f . g)
--   </pre>
class Foldable (t :: * -> *)

-- | Map each element of the structure to a monoid, and combine the
--   results.
foldMap :: (Foldable t, Monoid m) => a -> m -> t a -> m

-- | Right-associative fold of a structure.
--   
--   In the case of lists, <a>foldr</a>, when applied to a binary operator,
--   a starting value (typically the right-identity of the operator), and a
--   list, reduces the list using the binary operator, from right to left:
--   
--   <pre>
--   foldr f z [x1, x2, ..., xn] == x1 `f` (x2 `f` ... (xn `f` z)...)
--   </pre>
--   
--   Note that, since the head of the resulting expression is produced by
--   an application of the operator to the first element of the list,
--   <a>foldr</a> can produce a terminating expression from an infinite
--   list.
--   
--   For a general <a>Foldable</a> structure this should be semantically
--   identical to,
--   
--   <pre>
--   foldr f z = <a>foldr</a> f z . <a>toList</a>
--   </pre>
foldr :: Foldable t => a -> b -> b -> b -> t a -> b

-- | Left-associative fold of a structure.
--   
--   In the case of lists, <a>foldl</a>, when applied to a binary operator,
--   a starting value (typically the left-identity of the operator), and a
--   list, reduces the list using the binary operator, from left to right:
--   
--   <pre>
--   foldl f z [x1, x2, ..., xn] == (...((z `f` x1) `f` x2) `f`...) `f` xn
--   </pre>
--   
--   Note that to produce the outermost application of the operator the
--   entire input list must be traversed. This means that <a>foldl'</a>
--   will diverge if given an infinite list.
--   
--   Also note that if you want an efficient left-fold, you probably want
--   to use <a>foldl'</a> instead of <a>foldl</a>. The reason for this is
--   that latter does not force the "inner" results (e.g. <tt>z <tt>f</tt>
--   x1</tt> in the above example) before applying them to the operator
--   (e.g. to <tt>(<tt>f</tt> x2)</tt>). This results in a thunk chain
--   <tt>O(n)</tt> elements long, which then must be evaluated from the
--   outside-in.
--   
--   For a general <a>Foldable</a> structure this should be semantically
--   identical to,
--   
--   <pre>
--   foldl f z = <a>foldl</a> f z . <a>toList</a>
--   </pre>
foldl :: Foldable t => b -> a -> b -> b -> t a -> b

-- | A variant of <a>foldr</a> that has no base case, and thus may only be
--   applied to non-empty structures.
--   
--   <pre>
--   <a>foldr1</a> f = <a>foldr1</a> f . <a>toList</a>
--   </pre>
foldr1 :: Foldable t => a -> a -> a -> t a -> a

-- | A variant of <a>foldl</a> that has no base case, and thus may only be
--   applied to non-empty structures.
--   
--   <pre>
--   <a>foldl1</a> f = <a>foldl1</a> f . <a>toList</a>
--   </pre>
foldl1 :: Foldable t => a -> a -> a -> t a -> a

-- | Test whether the structure is empty. The default implementation is
--   optimized for structures that are similar to cons-lists, because there
--   is no general way to do better.
null :: Foldable t => t a -> Bool

-- | Returns the size/length of a finite structure as an <a>Int</a>. The
--   default implementation is optimized for structures that are similar to
--   cons-lists, because there is no general way to do better.
length :: Foldable t => t a -> Int

-- | Does the element occur in the structure?
elem :: (Foldable t, Eq a) => a -> t a -> Bool

-- | The largest element of a non-empty structure.
maximum :: (Foldable t, Ord a) => t a -> a

-- | The least element of a non-empty structure.
minimum :: (Foldable t, Ord a) => t a -> a

-- | The <a>sum</a> function computes the sum of the numbers of a
--   structure.
sum :: (Foldable t, Num a) => t a -> a

-- | The <a>product</a> function computes the product of the numbers of a
--   structure.
product :: (Foldable t, Num a) => t a -> a

-- | Functors representing data structures that can be traversed from left
--   to right.
--   
--   A definition of <a>traverse</a> must satisfy the following laws:
--   
--   <ul>
--   <li><i><i>naturality</i></i> <tt>t . <a>traverse</a> f =
--   <a>traverse</a> (t . f)</tt> for every applicative transformation
--   <tt>t</tt></li>
--   <li><i><i>identity</i></i> <tt><a>traverse</a> Identity =
--   Identity</tt></li>
--   <li><i><i>composition</i></i> <tt><a>traverse</a> (Compose .
--   <a>fmap</a> g . f) = Compose . <a>fmap</a> (<a>traverse</a> g) .
--   <a>traverse</a> f</tt></li>
--   </ul>
--   
--   A definition of <a>sequenceA</a> must satisfy the following laws:
--   
--   <ul>
--   <li><i><i>naturality</i></i> <tt>t . <a>sequenceA</a> =
--   <a>sequenceA</a> . <a>fmap</a> t</tt> for every applicative
--   transformation <tt>t</tt></li>
--   <li><i><i>identity</i></i> <tt><a>sequenceA</a> . <a>fmap</a> Identity
--   = Identity</tt></li>
--   <li><i><i>composition</i></i> <tt><a>sequenceA</a> . <a>fmap</a>
--   Compose = Compose . <a>fmap</a> <a>sequenceA</a> .
--   <a>sequenceA</a></tt></li>
--   </ul>
--   
--   where an <i>applicative transformation</i> is a function
--   
--   <pre>
--   t :: (Applicative f, Applicative g) =&gt; f a -&gt; g a
--   </pre>
--   
--   preserving the <a>Applicative</a> operations, i.e.
--   
--   <ul>
--   <li><pre>t (<a>pure</a> x) = <a>pure</a> x</pre></li>
--   <li><pre>t (x <a>&lt;*&gt;</a> y) = t x <a>&lt;*&gt;</a> t
--   y</pre></li>
--   </ul>
--   
--   and the identity functor <tt>Identity</tt> and composition of functors
--   <tt>Compose</tt> are defined as
--   
--   <pre>
--   newtype Identity a = Identity a
--   
--   instance Functor Identity where
--     fmap f (Identity x) = Identity (f x)
--   
--   instance Applicative Identity where
--     pure x = Identity x
--     Identity f &lt;*&gt; Identity x = Identity (f x)
--   
--   newtype Compose f g a = Compose (f (g a))
--   
--   instance (Functor f, Functor g) =&gt; Functor (Compose f g) where
--     fmap f (Compose x) = Compose (fmap (fmap f) x)
--   
--   instance (Applicative f, Applicative g) =&gt; Applicative (Compose f g) where
--     pure x = Compose (pure (pure x))
--     Compose f &lt;*&gt; Compose x = Compose ((&lt;*&gt;) &lt;$&gt; f &lt;*&gt; x)
--   </pre>
--   
--   (The naturality law is implied by parametricity.)
--   
--   Instances are similar to <a>Functor</a>, e.g. given a data type
--   
--   <pre>
--   data Tree a = Empty | Leaf a | Node (Tree a) a (Tree a)
--   </pre>
--   
--   a suitable instance would be
--   
--   <pre>
--   instance Traversable Tree where
--      traverse f Empty = pure Empty
--      traverse f (Leaf x) = Leaf &lt;$&gt; f x
--      traverse f (Node l k r) = Node &lt;$&gt; traverse f l &lt;*&gt; f k &lt;*&gt; traverse f r
--   </pre>
--   
--   This is suitable even for abstract types, as the laws for
--   <a>&lt;*&gt;</a> imply a form of associativity.
--   
--   The superclass instances should satisfy the following:
--   
--   <ul>
--   <li>In the <a>Functor</a> instance, <a>fmap</a> should be equivalent
--   to traversal with the identity applicative functor
--   (<a>fmapDefault</a>).</li>
--   <li>In the <a>Foldable</a> instance, <a>foldMap</a> should be
--   equivalent to traversal with a constant applicative functor
--   (<a>foldMapDefault</a>).</li>
--   </ul>
class (Functor t, Foldable t) => Traversable (t :: * -> *)

-- | Map each element of a structure to an action, evaluate these actions
--   from left to right, and collect the results. For a version that
--   ignores the results see <a>traverse_</a>.
traverse :: (Traversable t, Applicative f) => a -> f b -> t a -> f t b

-- | Evaluate each action in the structure from left to right, and and
--   collect the results. For a version that ignores the results see
--   <a>sequenceA_</a>.
sequenceA :: (Traversable t, Applicative f) => t f a -> f t a

-- | Map each element of a structure to a monadic action, evaluate these
--   actions from left to right, and collect the results. For a version
--   that ignores the results see <a>mapM_</a>.
mapM :: (Traversable t, Monad m) => a -> m b -> t a -> m t b

-- | Evaluate each monadic action in the structure from left to right, and
--   collect the results. For a version that ignores the results see
--   <a>sequence_</a>.
sequence :: (Traversable t, Monad m) => t m a -> m t a

-- | The class of semigroups (types with an associative binary operation).
--   
--   Instances should satisfy the associativity law:
--   
--   <ul>
--   <li><pre>x <a>&lt;&gt;</a> (y <a>&lt;&gt;</a> z) = (x <a>&lt;&gt;</a>
--   y) <a>&lt;&gt;</a> z</pre></li>
--   </ul>
class Semigroup a

-- | An associative operation.
(<>) :: Semigroup a => a -> a -> a

-- | The class of monoids (types with an associative binary operation that
--   has an identity). Instances should satisfy the following laws:
--   
--   <ul>
--   <li><pre>x <a>&lt;&gt;</a> <a>mempty</a> = x</pre></li>
--   <li><pre><a>mempty</a> <a>&lt;&gt;</a> x = x</pre></li>
--   <li><tt>x <a>&lt;&gt;</a> (y <a>&lt;&gt;</a> z) = (x <a>&lt;&gt;</a>
--   y) <a>&lt;&gt;</a> z</tt> (<a>Semigroup</a> law)</li>
--   <li><pre><a>mconcat</a> = <a>foldr</a> '(&lt;&gt;)'
--   <a>mempty</a></pre></li>
--   </ul>
--   
--   The method names refer to the monoid of lists under concatenation, but
--   there are many other instances.
--   
--   Some types can be viewed as a monoid in more than one way, e.g. both
--   addition and multiplication on numbers. In such cases we often define
--   <tt>newtype</tt>s and make those instances of <a>Monoid</a>, e.g.
--   <tt>Sum</tt> and <tt>Product</tt>.
--   
--   <b>NOTE</b>: <a>Semigroup</a> is a superclass of <a>Monoid</a> since
--   <i>base-4.11.0.0</i>.
class Semigroup a => Monoid a

-- | Identity of <a>mappend</a>
mempty :: Monoid a => a

-- | An associative operation
--   
--   <b>NOTE</b>: This method is redundant and has the default
--   implementation <tt><a>mappend</a> = '(&lt;&gt;)'</tt> since
--   <i>base-4.11.0.0</i>.
mappend :: Monoid a => a -> a -> a

-- | Fold a list using the monoid.
--   
--   For most types, the default definition for <a>mconcat</a> will be
--   used, but the function is included in the class definition so that an
--   optimized version can be provided for specific types.
mconcat :: Monoid a => [a] -> a
data Bool
False :: Bool
True :: Bool

-- | The character type <a>Char</a> is an enumeration whose values
--   represent Unicode (or equivalently ISO/IEC 10646) code points (i.e.
--   characters, see <a>http://www.unicode.org/</a> for details). This set
--   extends the ISO 8859-1 (Latin-1) character set (the first 256
--   characters), which is itself an extension of the ASCII character set
--   (the first 128 characters). A character literal in Haskell has type
--   <a>Char</a>.
--   
--   To convert a <a>Char</a> to or from the corresponding <a>Int</a> value
--   defined by Unicode, use <a>toEnum</a> and <a>fromEnum</a> from the
--   <a>Enum</a> class respectively (or equivalently <tt>ord</tt> and
--   <tt>chr</tt>).
data Char

-- | Double-precision floating point numbers. It is desirable that this
--   type be at least equal in range and precision to the IEEE
--   double-precision type.
data Double

-- | Single-precision floating point numbers. It is desirable that this
--   type be at least equal in range and precision to the IEEE
--   single-precision type.
data Float

-- | A fixed-precision integer type with at least the range <tt>[-2^29 ..
--   2^29-1]</tt>. The exact range for a given implementation can be
--   determined by using <a>minBound</a> and <a>maxBound</a> from the
--   <a>Bounded</a> class.
data Int

-- | Invariant: <a>Jn#</a> and <a>Jp#</a> are used iff value doesn't fit in
--   <a>S#</a>
--   
--   Useful properties resulting from the invariants:
--   
--   <ul>
--   <li><pre>abs (<a>S#</a> _) &lt;= abs (<a>Jp#</a> _)</pre></li>
--   <li><pre>abs (<a>S#</a> _) &lt; abs (<a>Jn#</a> _)</pre></li>
--   </ul>
data Integer

-- | The <a>Maybe</a> type encapsulates an optional value. A value of type
--   <tt><a>Maybe</a> a</tt> either contains a value of type <tt>a</tt>
--   (represented as <tt><a>Just</a> a</tt>), or it is empty (represented
--   as <a>Nothing</a>). Using <a>Maybe</a> is a good way to deal with
--   errors or exceptional cases without resorting to drastic measures such
--   as <a>error</a>.
--   
--   The <a>Maybe</a> type is also a monad. It is a simple kind of error
--   monad, where all errors are represented by <a>Nothing</a>. A richer
--   error monad can be built using the <a>Either</a> type.
data Maybe a
Nothing :: Maybe a
Just :: a -> Maybe a
data Ordering
LT :: Ordering
EQ :: Ordering
GT :: Ordering

-- | Arbitrary-precision rational numbers, represented as a ratio of two
--   <a>Integer</a> values. A rational number may be constructed using the
--   <a>%</a> operator.
type Rational = Ratio Integer

-- | A value of type <tt><a>IO</a> a</tt> is a computation which, when
--   performed, does some I/O before returning a value of type <tt>a</tt>.
--   
--   There is really only one way to "perform" an I/O action: bind it to
--   <tt>Main.main</tt> in your program. When your program is run, the I/O
--   will be performed. It isn't possible to perform I/O from an arbitrary
--   function, unless that function is itself in the <a>IO</a> monad and
--   called at some point, directly or indirectly, from <tt>Main.main</tt>.
--   
--   <a>IO</a> is a monad, so <a>IO</a> actions can be combined using
--   either the do-notation or the <tt>&gt;&gt;</tt> and <tt>&gt;&gt;=</tt>
--   operations from the <tt>Monad</tt> class.
data IO a

-- | A <a>Word</a> is an unsigned integral type, with the same size as
--   <a>Int</a>.
data Word

-- | The <a>Either</a> type represents values with two possibilities: a
--   value of type <tt><a>Either</a> a b</tt> is either <tt><a>Left</a>
--   a</tt> or <tt><a>Right</a> b</tt>.
--   
--   The <a>Either</a> type is sometimes used to represent a value which is
--   either correct or an error; by convention, the <a>Left</a> constructor
--   is used to hold an error value and the <a>Right</a> constructor is
--   used to hold a correct value (mnemonic: "right" also means "correct").
--   
--   <h4><b>Examples</b></h4>
--   
--   The type <tt><a>Either</a> <a>String</a> <a>Int</a></tt> is the type
--   of values which can be either a <a>String</a> or an <a>Int</a>. The
--   <a>Left</a> constructor can be used only on <a>String</a>s, and the
--   <a>Right</a> constructor can be used only on <a>Int</a>s:
--   
--   <pre>
--   &gt;&gt;&gt; let s = Left "foo" :: Either String Int
--   
--   &gt;&gt;&gt; s
--   Left "foo"
--   
--   &gt;&gt;&gt; let n = Right 3 :: Either String Int
--   
--   &gt;&gt;&gt; n
--   Right 3
--   
--   &gt;&gt;&gt; :type s
--   s :: Either String Int
--   
--   &gt;&gt;&gt; :type n
--   n :: Either String Int
--   </pre>
--   
--   The <a>fmap</a> from our <a>Functor</a> instance will ignore
--   <a>Left</a> values, but will apply the supplied function to values
--   contained in a <a>Right</a>:
--   
--   <pre>
--   &gt;&gt;&gt; let s = Left "foo" :: Either String Int
--   
--   &gt;&gt;&gt; let n = Right 3 :: Either String Int
--   
--   &gt;&gt;&gt; fmap (*2) s
--   Left "foo"
--   
--   &gt;&gt;&gt; fmap (*2) n
--   Right 6
--   </pre>
--   
--   The <a>Monad</a> instance for <a>Either</a> allows us to chain
--   together multiple actions which may fail, and fail overall if any of
--   the individual steps failed. First we'll write a function that can
--   either parse an <a>Int</a> from a <a>Char</a>, or fail.
--   
--   <pre>
--   &gt;&gt;&gt; import Data.Char ( digitToInt, isDigit )
--   
--   &gt;&gt;&gt; :{
--       let parseEither :: Char -&gt; Either String Int
--           parseEither c
--             | isDigit c = Right (digitToInt c)
--             | otherwise = Left "parse error"
--   
--   &gt;&gt;&gt; :}
--   </pre>
--   
--   The following should work, since both <tt>'1'</tt> and <tt>'2'</tt>
--   can be parsed as <a>Int</a>s.
--   
--   <pre>
--   &gt;&gt;&gt; :{
--       let parseMultiple :: Either String Int
--           parseMultiple = do
--             x &lt;- parseEither '1'
--             y &lt;- parseEither '2'
--             return (x + y)
--   
--   &gt;&gt;&gt; :}
--   </pre>
--   
--   <pre>
--   &gt;&gt;&gt; parseMultiple
--   Right 3
--   </pre>
--   
--   But the following should fail overall, since the first operation where
--   we attempt to parse <tt>'m'</tt> as an <a>Int</a> will fail:
--   
--   <pre>
--   &gt;&gt;&gt; :{
--       let parseMultiple :: Either String Int
--           parseMultiple = do
--             x &lt;- parseEither 'm'
--             y &lt;- parseEither '2'
--             return (x + y)
--   
--   &gt;&gt;&gt; :}
--   </pre>
--   
--   <pre>
--   &gt;&gt;&gt; parseMultiple
--   Left "parse error"
--   </pre>
data Either a b
Left :: a -> Either a b
Right :: b -> Either a b

-- | A <a>String</a> is a list of characters. String constants in Haskell
--   are values of type <a>String</a>.
type String = [Char]

-- | An infix synonym for <a>fmap</a>.
--   
--   The name of this operator is an allusion to <tt>$</tt>. Note the
--   similarities between their types:
--   
--   <pre>
--    ($)  ::              (a -&gt; b) -&gt;   a -&gt;   b
--   (&lt;$&gt;) :: Functor f =&gt; (a -&gt; b) -&gt; f a -&gt; f b
--   </pre>
--   
--   Whereas <tt>$</tt> is function application, <a>&lt;$&gt;</a> is
--   function application lifted over a <a>Functor</a>.
--   
--   <h4><b>Examples</b></h4>
--   
--   Convert from a <tt><tt>Maybe</tt> <tt>Int</tt></tt> to a
--   <tt><tt>Maybe</tt> <tt>String</tt></tt> using <tt>show</tt>:
--   
--   <pre>
--   &gt;&gt;&gt; show &lt;$&gt; Nothing
--   Nothing
--   
--   &gt;&gt;&gt; show &lt;$&gt; Just 3
--   Just "3"
--   </pre>
--   
--   Convert from an <tt><tt>Either</tt> <tt>Int</tt> <tt>Int</tt></tt> to
--   an <tt><tt>Either</tt> <tt>Int</tt></tt> <tt>String</tt> using
--   <tt>show</tt>:
--   
--   <pre>
--   &gt;&gt;&gt; show &lt;$&gt; Left 17
--   Left 17
--   
--   &gt;&gt;&gt; show &lt;$&gt; Right 17
--   Right "17"
--   </pre>
--   
--   Double each element of a list:
--   
--   <pre>
--   &gt;&gt;&gt; (*2) &lt;$&gt; [1,2,3]
--   [2,4,6]
--   </pre>
--   
--   Apply <tt>even</tt> to the second element of a pair:
--   
--   <pre>
--   &gt;&gt;&gt; even &lt;$&gt; (2,2)
--   (2,True)
--   </pre>
(<$>) :: Functor f => a -> b -> f a -> f b
infixl 4 <$>

-- | The <tt>shows</tt> functions return a function that prepends the
--   output <a>String</a> to an existing <a>String</a>. This allows
--   constant-time concatenation of results using function composition.
type ShowS = String -> String

-- | The <a>read</a> function reads input from a string, which must be
--   completely consumed by the input process. <a>read</a> fails with an
--   <a>error</a> if the parse is unsuccessful, and it is therefore
--   discouraged from being used in real applications. Use <a>readMaybe</a>
--   or <a>readEither</a> for safe alternatives.
--   
--   <pre>
--   &gt;&gt;&gt; read "123" :: Int
--   123
--   </pre>
--   
--   <pre>
--   &gt;&gt;&gt; read "hello" :: Int
--   *** Exception: Prelude.read: no parse
--   </pre>
read :: Read a => String -> a

-- | The <a>readIO</a> function is similar to <a>read</a> except that it
--   signals parse failure to the <a>IO</a> monad instead of terminating
--   the program.
readIO :: Read a => String -> IO a

-- | The <a>readLn</a> function combines <a>getLine</a> and <a>readIO</a>.
readLn :: Read a => IO a

-- | The computation <a>appendFile</a> <tt>file str</tt> function appends
--   the string <tt>str</tt>, to the file <tt>file</tt>.
--   
--   Note that <a>writeFile</a> and <a>appendFile</a> write a literal
--   string to a file. To write a value of any printable type, as with
--   <a>print</a>, use the <a>show</a> function to convert the value to a
--   string first.
--   
--   <pre>
--   main = appendFile "squares" (show [(x,x*x) | x &lt;- [0,0.1..2]])
--   </pre>
appendFile :: FilePath -> String -> IO ()

-- | The computation <a>writeFile</a> <tt>file str</tt> function writes the
--   string <tt>str</tt>, to the file <tt>file</tt>.
writeFile :: FilePath -> String -> IO ()

-- | The <a>readFile</a> function reads a file and returns the contents of
--   the file as a string. The file is read lazily, on demand, as with
--   <a>getContents</a>.
readFile :: FilePath -> IO String

-- | The <a>interact</a> function takes a function of type
--   <tt>String-&gt;String</tt> as its argument. The entire input from the
--   standard input device is passed to this function as its argument, and
--   the resulting string is output on the standard output device.
interact :: String -> String -> IO ()

-- | The <a>getContents</a> operation returns all user input as a single
--   string, which is read lazily as it is needed (same as
--   <a>hGetContents</a> <a>stdin</a>).
getContents :: IO String

-- | Read a line from the standard input device (same as <a>hGetLine</a>
--   <a>stdin</a>).
getLine :: IO String

-- | Read a character from the standard input device (same as
--   <a>hGetChar</a> <a>stdin</a>).
getChar :: IO Char

-- | The same as <a>putStr</a>, but adds a newline character.
putStrLn :: String -> IO ()

-- | Write a string to the standard output device (same as <a>hPutStr</a>
--   <a>stdout</a>).
putStr :: String -> IO ()

-- | Write a character to the standard output device (same as
--   <a>hPutChar</a> <a>stdout</a>).
putChar :: Char -> IO ()

-- | Raise an <a>IOError</a> in the <a>IO</a> monad.
ioError :: () => IOError -> IO a

-- | File and directory names are values of type <a>String</a>, whose
--   precise meaning is operating system dependent. Files can be opened,
--   yielding a handle which can then be used to operate on the contents of
--   that file.
type FilePath = String

-- | Construct an <a>IOError</a> value with a string describing the error.
--   The <a>fail</a> method of the <a>IO</a> instance of the <a>Monad</a>
--   class raises a <a>userError</a>, thus:
--   
--   <pre>
--   instance Monad IO where
--     ...
--     fail s = ioError (userError s)
--   </pre>
userError :: String -> IOError

-- | The Haskell 2010 type for exceptions in the <a>IO</a> monad. Any I/O
--   operation may raise an <a>IOError</a> instead of returning a result.
--   For a more general type of exception, including also those that arise
--   in pure code, see <a>Exception</a>.
--   
--   In Haskell 2010, this is an opaque type.
type IOError = IOException

-- | <a>notElem</a> is the negation of <a>elem</a>.
notElem :: (Foldable t, Eq a) => a -> t a -> Bool
infix 4 `notElem`

-- | Determines whether all elements of the structure satisfy the
--   predicate.
all :: Foldable t => a -> Bool -> t a -> Bool

-- | Determines whether any element of the structure satisfies the
--   predicate.
any :: Foldable t => a -> Bool -> t a -> Bool

-- | <a>or</a> returns the disjunction of a container of Bools. For the
--   result to be <a>False</a>, the container must be finite; <a>True</a>,
--   however, results from a <a>True</a> value finitely far from the left
--   end.
or :: Foldable t => t Bool -> Bool

-- | <a>and</a> returns the conjunction of a container of Bools. For the
--   result to be <a>True</a>, the container must be finite; <a>False</a>,
--   however, results from a <a>False</a> value finitely far from the left
--   end.
and :: Foldable t => t Bool -> Bool

-- | Map a function over all the elements of a container and concatenate
--   the resulting lists.
concatMap :: Foldable t => a -> [b] -> t a -> [b]

-- | The concatenation of all the elements of a container of lists.
concat :: Foldable t => t [a] -> [a]

-- | Evaluate each monadic action in the structure from left to right, and
--   ignore the results. For a version that doesn't ignore the results see
--   <a>sequence</a>.
--   
--   As of base 4.8.0.0, <a>sequence_</a> is just <a>sequenceA_</a>,
--   specialized to <a>Monad</a>.
sequence_ :: (Foldable t, Monad m) => t m a -> m ()

-- | Map each element of a structure to a monadic action, evaluate these
--   actions from left to right, and ignore the results. For a version that
--   doesn't ignore the results see <a>mapM</a>.
--   
--   As of base 4.8.0.0, <a>mapM_</a> is just <a>traverse_</a>, specialized
--   to <a>Monad</a>.
mapM_ :: (Foldable t, Monad m) => a -> m b -> t a -> m ()

-- | <a>unwords</a> is an inverse operation to <a>words</a>. It joins words
--   with separating spaces.
--   
--   <pre>
--   &gt;&gt;&gt; unwords ["Lorem", "ipsum", "dolor"]
--   "Lorem ipsum dolor"
--   </pre>
unwords :: [String] -> String

-- | <a>words</a> breaks a string up into a list of words, which were
--   delimited by white space.
--   
--   <pre>
--   &gt;&gt;&gt; words "Lorem ipsum\ndolor"
--   ["Lorem","ipsum","dolor"]
--   </pre>
words :: String -> [String]

-- | <a>unlines</a> is an inverse operation to <a>lines</a>. It joins
--   lines, after appending a terminating newline to each.
--   
--   <pre>
--   &gt;&gt;&gt; unlines ["Hello", "World", "!"]
--   "Hello\nWorld\n!\n"
--   </pre>
unlines :: [String] -> String

-- | <a>lines</a> breaks a string up into a list of strings at newline
--   characters. The resulting strings do not contain newlines.
--   
--   Note that after splitting the string at newline characters, the last
--   part of the string is considered a line even if it doesn't end with a
--   newline. For example,
--   
--   <pre>
--   &gt;&gt;&gt; lines ""
--   []
--   </pre>
--   
--   <pre>
--   &gt;&gt;&gt; lines "\n"
--   [""]
--   </pre>
--   
--   <pre>
--   &gt;&gt;&gt; lines "one"
--   ["one"]
--   </pre>
--   
--   <pre>
--   &gt;&gt;&gt; lines "one\n"
--   ["one"]
--   </pre>
--   
--   <pre>
--   &gt;&gt;&gt; lines "one\n\n"
--   ["one",""]
--   </pre>
--   
--   <pre>
--   &gt;&gt;&gt; lines "one\ntwo"
--   ["one","two"]
--   </pre>
--   
--   <pre>
--   &gt;&gt;&gt; lines "one\ntwo\n"
--   ["one","two"]
--   </pre>
--   
--   Thus <tt><a>lines</a> s</tt> contains at least as many elements as
--   newlines in <tt>s</tt>.
lines :: String -> [String]

-- | equivalent to <a>readsPrec</a> with a precedence of 0.
reads :: Read a => ReadS a

-- | Case analysis for the <a>Either</a> type. If the value is
--   <tt><a>Left</a> a</tt>, apply the first function to <tt>a</tt>; if it
--   is <tt><a>Right</a> b</tt>, apply the second function to <tt>b</tt>.
--   
--   <h4><b>Examples</b></h4>
--   
--   We create two values of type <tt><a>Either</a> <a>String</a>
--   <a>Int</a></tt>, one using the <a>Left</a> constructor and another
--   using the <a>Right</a> constructor. Then we apply "either" the
--   <tt>length</tt> function (if we have a <a>String</a>) or the
--   "times-two" function (if we have an <a>Int</a>):
--   
--   <pre>
--   &gt;&gt;&gt; let s = Left "foo" :: Either String Int
--   
--   &gt;&gt;&gt; let n = Right 3 :: Either String Int
--   
--   &gt;&gt;&gt; either length (*2) s
--   3
--   
--   &gt;&gt;&gt; either length (*2) n
--   6
--   </pre>
either :: () => a -> c -> b -> c -> Either a b -> c

-- | The <a>lex</a> function reads a single lexeme from the input,
--   discarding initial white space, and returning the characters that
--   constitute the lexeme. If the input string contains only white space,
--   <a>lex</a> returns a single successful `lexeme' consisting of the
--   empty string. (Thus <tt><a>lex</a> "" = [("","")]</tt>.) If there is
--   no legal lexeme at the beginning of the input string, <a>lex</a> fails
--   (i.e. returns <tt>[]</tt>).
--   
--   This lexer is not completely faithful to the Haskell lexical syntax in
--   the following respects:
--   
--   <ul>
--   <li>Qualified names are not handled properly</li>
--   <li>Octal and hexadecimal numerics are not recognized as a single
--   token</li>
--   <li>Comments are not treated properly</li>
--   </ul>
lex :: ReadS String

-- | <tt><a>readParen</a> <a>True</a> p</tt> parses what <tt>p</tt> parses,
--   but surrounded with parentheses.
--   
--   <tt><a>readParen</a> <a>False</a> p</tt> parses what <tt>p</tt>
--   parses, but optionally surrounded with parentheses.
readParen :: () => Bool -> ReadS a -> ReadS a

-- | A parser for a type <tt>a</tt>, represented as a function that takes a
--   <a>String</a> and returns a list of possible parses as
--   <tt>(a,<a>String</a>)</tt> pairs.
--   
--   Note that this kind of backtracking parser is very inefficient;
--   reading a large structure may be quite slow (cf <a>ReadP</a>).
type ReadS a = String -> [(a, String)]

-- | <tt><a>lcm</a> x y</tt> is the smallest positive integer that both
--   <tt>x</tt> and <tt>y</tt> divide.
lcm :: Integral a => a -> a -> a

-- | <tt><a>gcd</a> x y</tt> is the non-negative factor of both <tt>x</tt>
--   and <tt>y</tt> of which every common factor of <tt>x</tt> and
--   <tt>y</tt> is also a factor; for example <tt><a>gcd</a> 4 2 = 2</tt>,
--   <tt><a>gcd</a> (-4) 6 = 2</tt>, <tt><a>gcd</a> 0 4</tt> = <tt>4</tt>.
--   <tt><a>gcd</a> 0 0</tt> = <tt>0</tt>. (That is, the common divisor
--   that is "greatest" in the divisibility preordering.)
--   
--   Note: Since for signed fixed-width integer types, <tt><a>abs</a>
--   <a>minBound</a> &lt; 0</tt>, the result may be negative if one of the
--   arguments is <tt><a>minBound</a></tt> (and necessarily is if the other
--   is <tt>0</tt> or <tt><a>minBound</a></tt>) for such types.
gcd :: Integral a => a -> a -> a

-- | raise a number to an integral power
(^^) :: (Fractional a, Integral b) => a -> b -> a
infixr 8 ^^

-- | raise a number to a non-negative integral power
(^) :: (Num a, Integral b) => a -> b -> a
infixr 8 ^
odd :: Integral a => a -> Bool
even :: Integral a => a -> Bool

-- | utility function that surrounds the inner show function with
--   parentheses when the <a>Bool</a> parameter is <a>True</a>.
showParen :: Bool -> ShowS -> ShowS

-- | utility function converting a <a>String</a> to a show function that
--   simply prepends the string unchanged.
showString :: String -> ShowS

-- | utility function converting a <a>Char</a> to a show function that
--   simply prepends the character unchanged.
showChar :: Char -> ShowS

-- | equivalent to <a>showsPrec</a> with a precedence of 0.
shows :: Show a => a -> ShowS

-- | The <a>unzip3</a> function takes a list of triples and returns three
--   lists, analogous to <a>unzip</a>.
unzip3 :: () => [(a, b, c)] -> ([a], [b], [c])

-- | <a>unzip</a> transforms a list of pairs into a list of first
--   components and a list of second components.
unzip :: () => [(a, b)] -> ([a], [b])

-- | The <a>zipWith3</a> function takes a function which combines three
--   elements, as well as three lists and returns a list of their
--   point-wise combination, analogous to <a>zipWith</a>.
zipWith3 :: () => a -> b -> c -> d -> [a] -> [b] -> [c] -> [d]

-- | <a>zipWith</a> generalises <a>zip</a> by zipping with the function
--   given as the first argument, instead of a tupling function. For
--   example, <tt><a>zipWith</a> (+)</tt> is applied to two lists to
--   produce the list of corresponding sums.
--   
--   <a>zipWith</a> is right-lazy:
--   
--   <pre>
--   zipWith f [] _|_ = []
--   </pre>
zipWith :: () => a -> b -> c -> [a] -> [b] -> [c]

-- | <a>zip3</a> takes three lists and returns a list of triples, analogous
--   to <a>zip</a>.
zip3 :: () => [a] -> [b] -> [c] -> [(a, b, c)]

-- | List index (subscript) operator, starting from 0. It is an instance of
--   the more general <a>genericIndex</a>, which takes an index of any
--   integral type.
(!!) :: () => [a] -> Int -> a
infixl 9 !!

-- | <a>lookup</a> <tt>key assocs</tt> looks up a key in an association
--   list.
lookup :: Eq a => a -> [(a, b)] -> Maybe b

-- | <a>reverse</a> <tt>xs</tt> returns the elements of <tt>xs</tt> in
--   reverse order. <tt>xs</tt> must be finite.
reverse :: () => [a] -> [a]

-- | <a>break</a>, applied to a predicate <tt>p</tt> and a list
--   <tt>xs</tt>, returns a tuple where first element is longest prefix
--   (possibly empty) of <tt>xs</tt> of elements that <i>do not satisfy</i>
--   <tt>p</tt> and second element is the remainder of the list:
--   
--   <pre>
--   break (&gt; 3) [1,2,3,4,1,2,3,4] == ([1,2,3],[4,1,2,3,4])
--   break (&lt; 9) [1,2,3] == ([],[1,2,3])
--   break (&gt; 9) [1,2,3] == ([1,2,3],[])
--   </pre>
--   
--   <a>break</a> <tt>p</tt> is equivalent to <tt><a>span</a> (<a>not</a> .
--   p)</tt>.
break :: () => a -> Bool -> [a] -> ([a], [a])

-- | <a>span</a>, applied to a predicate <tt>p</tt> and a list <tt>xs</tt>,
--   returns a tuple where first element is longest prefix (possibly empty)
--   of <tt>xs</tt> of elements that satisfy <tt>p</tt> and second element
--   is the remainder of the list:
--   
--   <pre>
--   span (&lt; 3) [1,2,3,4,1,2,3,4] == ([1,2],[3,4,1,2,3,4])
--   span (&lt; 9) [1,2,3] == ([1,2,3],[])
--   span (&lt; 0) [1,2,3] == ([],[1,2,3])
--   </pre>
--   
--   <a>span</a> <tt>p xs</tt> is equivalent to <tt>(<a>takeWhile</a> p xs,
--   <a>dropWhile</a> p xs)</tt>
span :: () => a -> Bool -> [a] -> ([a], [a])

-- | <a>splitAt</a> <tt>n xs</tt> returns a tuple where first element is
--   <tt>xs</tt> prefix of length <tt>n</tt> and second element is the
--   remainder of the list:
--   
--   <pre>
--   splitAt 6 "Hello World!" == ("Hello ","World!")
--   splitAt 3 [1,2,3,4,5] == ([1,2,3],[4,5])
--   splitAt 1 [1,2,3] == ([1],[2,3])
--   splitAt 3 [1,2,3] == ([1,2,3],[])
--   splitAt 4 [1,2,3] == ([1,2,3],[])
--   splitAt 0 [1,2,3] == ([],[1,2,3])
--   splitAt (-1) [1,2,3] == ([],[1,2,3])
--   </pre>
--   
--   It is equivalent to <tt>(<a>take</a> n xs, <a>drop</a> n xs)</tt> when
--   <tt>n</tt> is not <tt>_|_</tt> (<tt>splitAt _|_ xs = _|_</tt>).
--   <a>splitAt</a> is an instance of the more general
--   <a>genericSplitAt</a>, in which <tt>n</tt> may be of any integral
--   type.
splitAt :: () => Int -> [a] -> ([a], [a])

-- | <a>drop</a> <tt>n xs</tt> returns the suffix of <tt>xs</tt> after the
--   first <tt>n</tt> elements, or <tt>[]</tt> if <tt>n &gt; <a>length</a>
--   xs</tt>:
--   
--   <pre>
--   drop 6 "Hello World!" == "World!"
--   drop 3 [1,2,3,4,5] == [4,5]
--   drop 3 [1,2] == []
--   drop 3 [] == []
--   drop (-1) [1,2] == [1,2]
--   drop 0 [1,2] == [1,2]
--   </pre>
--   
--   It is an instance of the more general <a>genericDrop</a>, in which
--   <tt>n</tt> may be of any integral type.
drop :: () => Int -> [a] -> [a]

-- | <a>take</a> <tt>n</tt>, applied to a list <tt>xs</tt>, returns the
--   prefix of <tt>xs</tt> of length <tt>n</tt>, or <tt>xs</tt> itself if
--   <tt>n &gt; <a>length</a> xs</tt>:
--   
--   <pre>
--   take 5 "Hello World!" == "Hello"
--   take 3 [1,2,3,4,5] == [1,2,3]
--   take 3 [1,2] == [1,2]
--   take 3 [] == []
--   take (-1) [1,2] == []
--   take 0 [1,2] == []
--   </pre>
--   
--   It is an instance of the more general <a>genericTake</a>, in which
--   <tt>n</tt> may be of any integral type.
take :: () => Int -> [a] -> [a]

-- | <a>dropWhile</a> <tt>p xs</tt> returns the suffix remaining after
--   <a>takeWhile</a> <tt>p xs</tt>:
--   
--   <pre>
--   dropWhile (&lt; 3) [1,2,3,4,5,1,2,3] == [3,4,5,1,2,3]
--   dropWhile (&lt; 9) [1,2,3] == []
--   dropWhile (&lt; 0) [1,2,3] == [1,2,3]
--   </pre>
dropWhile :: () => a -> Bool -> [a] -> [a]

-- | <a>takeWhile</a>, applied to a predicate <tt>p</tt> and a list
--   <tt>xs</tt>, returns the longest prefix (possibly empty) of
--   <tt>xs</tt> of elements that satisfy <tt>p</tt>:
--   
--   <pre>
--   takeWhile (&lt; 3) [1,2,3,4,1,2,3,4] == [1,2]
--   takeWhile (&lt; 9) [1,2,3] == [1,2,3]
--   takeWhile (&lt; 0) [1,2,3] == []
--   </pre>
takeWhile :: () => a -> Bool -> [a] -> [a]

-- | <a>cycle</a> ties a finite list into a circular one, or equivalently,
--   the infinite repetition of the original list. It is the identity on
--   infinite lists.
cycle :: () => [a] -> [a]

-- | <a>replicate</a> <tt>n x</tt> is a list of length <tt>n</tt> with
--   <tt>x</tt> the value of every element. It is an instance of the more
--   general <a>genericReplicate</a>, in which <tt>n</tt> may be of any
--   integral type.
replicate :: () => Int -> a -> [a]

-- | <a>repeat</a> <tt>x</tt> is an infinite list, with <tt>x</tt> the
--   value of every element.
repeat :: () => a -> [a]

-- | <a>iterate</a> <tt>f x</tt> returns an infinite list of repeated
--   applications of <tt>f</tt> to <tt>x</tt>:
--   
--   <pre>
--   iterate f x == [x, f x, f (f x), ...]
--   </pre>
--   
--   Note that <a>iterate</a> is lazy, potentially leading to thunk
--   build-up if the consumer doesn't force each iterate. See 'iterate\''
--   for a strict variant of this function.
iterate :: () => a -> a -> a -> [a]

-- | <a>scanr1</a> is a variant of <a>scanr</a> that has no starting value
--   argument.
scanr1 :: () => a -> a -> a -> [a] -> [a]

-- | <a>scanr</a> is the right-to-left dual of <a>scanl</a>. Note that
--   
--   <pre>
--   head (scanr f z xs) == foldr f z xs.
--   </pre>
scanr :: () => a -> b -> b -> b -> [a] -> [b]

-- | <a>scanl1</a> is a variant of <a>scanl</a> that has no starting value
--   argument:
--   
--   <pre>
--   scanl1 f [x1, x2, ...] == [x1, x1 `f` x2, ...]
--   </pre>
scanl1 :: () => a -> a -> a -> [a] -> [a]

-- | <a>scanl</a> is similar to <a>foldl</a>, but returns a list of
--   successive reduced values from the left:
--   
--   <pre>
--   scanl f z [x1, x2, ...] == [z, z `f` x1, (z `f` x1) `f` x2, ...]
--   </pre>
--   
--   Note that
--   
--   <pre>
--   last (scanl f z xs) == foldl f z xs.
--   </pre>
scanl :: () => b -> a -> b -> b -> [a] -> [b]

-- | Return all the elements of a list except the last one. The list must
--   be non-empty.
init :: () => [a] -> [a]

-- | Extract the last element of a list, which must be finite and
--   non-empty.
last :: () => [a] -> a

-- | Extract the elements after the head of a list, which must be
--   non-empty.
tail :: () => [a] -> [a]

-- | Extract the first element of a list, which must be non-empty.
head :: () => [a] -> a

-- | The <a>maybe</a> function takes a default value, a function, and a
--   <a>Maybe</a> value. If the <a>Maybe</a> value is <a>Nothing</a>, the
--   function returns the default value. Otherwise, it applies the function
--   to the value inside the <a>Just</a> and returns the result.
--   
--   <h4><b>Examples</b></h4>
--   
--   Basic usage:
--   
--   <pre>
--   &gt;&gt;&gt; maybe False odd (Just 3)
--   True
--   </pre>
--   
--   <pre>
--   &gt;&gt;&gt; maybe False odd Nothing
--   False
--   </pre>
--   
--   Read an integer from a string using <tt>readMaybe</tt>. If we succeed,
--   return twice the integer; that is, apply <tt>(*2)</tt> to it. If
--   instead we fail to parse an integer, return <tt>0</tt> by default:
--   
--   <pre>
--   &gt;&gt;&gt; import Text.Read ( readMaybe )
--   
--   &gt;&gt;&gt; maybe 0 (*2) (readMaybe "5")
--   10
--   
--   &gt;&gt;&gt; maybe 0 (*2) (readMaybe "")
--   0
--   </pre>
--   
--   Apply <tt>show</tt> to a <tt>Maybe Int</tt>. If we have <tt>Just
--   n</tt>, we want to show the underlying <a>Int</a> <tt>n</tt>. But if
--   we have <a>Nothing</a>, we return the empty string instead of (for
--   example) "Nothing":
--   
--   <pre>
--   &gt;&gt;&gt; maybe "" show (Just 5)
--   "5"
--   
--   &gt;&gt;&gt; maybe "" show Nothing
--   ""
--   </pre>
maybe :: () => b -> a -> b -> Maybe a -> b

-- | <a>uncurry</a> converts a curried function to a function on pairs.
--   
--   <h4><b>Examples</b></h4>
--   
--   <pre>
--   &gt;&gt;&gt; uncurry (+) (1,2)
--   3
--   </pre>
--   
--   <pre>
--   &gt;&gt;&gt; uncurry ($) (show, 1)
--   "1"
--   </pre>
--   
--   <pre>
--   &gt;&gt;&gt; map (uncurry max) [(1,2), (3,4), (6,8)]
--   [2,4,8]
--   </pre>
uncurry :: () => a -> b -> c -> (a, b) -> c

-- | <a>curry</a> converts an uncurried function to a curried function.
--   
--   <h4><b>Examples</b></h4>
--   
--   <pre>
--   &gt;&gt;&gt; curry fst 1 2
--   1
--   </pre>
curry :: () => (a, b) -> c -> a -> b -> c

-- | the same as <tt><a>flip</a> (<a>-</a>)</tt>.
--   
--   Because <tt>-</tt> is treated specially in the Haskell grammar,
--   <tt>(-</tt> <i>e</i><tt>)</tt> is not a section, but an application of
--   prefix negation. However, <tt>(<a>subtract</a></tt>
--   <i>exp</i><tt>)</tt> is equivalent to the disallowed section.
subtract :: Num a => a -> a -> a

-- | <a>asTypeOf</a> is a type-restricted version of <a>const</a>. It is
--   usually used as an infix operator, and its typing forces its first
--   argument (which is usually overloaded) to have the same type as the
--   second.
asTypeOf :: () => a -> a -> a

-- | <tt><a>until</a> p f</tt> yields the result of applying <tt>f</tt>
--   until <tt>p</tt> holds.
until :: () => a -> Bool -> a -> a -> a -> a

-- | <tt><a>flip</a> f</tt> takes its (first) two arguments in the reverse
--   order of <tt>f</tt>.
--   
--   <pre>
--   &gt;&gt;&gt; flip (++) "hello" "world"
--   "worldhello"
--   </pre>
flip :: () => a -> b -> c -> b -> a -> c

-- | Function composition.
(.) :: () => b -> c -> a -> b -> a -> c
infixr 9 .

-- | <tt>const x</tt> is a unary function which evaluates to <tt>x</tt> for
--   all inputs.
--   
--   <pre>
--   &gt;&gt;&gt; const 42 "hello"
--   42
--   </pre>
--   
--   <pre>
--   &gt;&gt;&gt; map (const 42) [0..3]
--   [42,42,42,42]
--   </pre>
const :: () => a -> b -> a

-- | Identity function.
--   
--   <pre>
--   id x = x
--   </pre>
id :: () => a -> a

-- | Same as <a>&gt;&gt;=</a>, but with the arguments interchanged.
(=<<) :: Monad m => a -> m b -> m a -> m b
infixr 1 =<<

-- | A special case of <a>error</a>. It is expected that compilers will
--   recognize this and insert error messages which are more appropriate to
--   the context in which <a>undefined</a> appears.
undefined :: HasCallStack => a

-- | A variant of <a>error</a> that does not produce a stack trace.
errorWithoutStackTrace :: () => [Char] -> a

-- | <a>error</a> stops execution and displays an error message.
error :: HasCallStack => [Char] -> a

-- | Boolean "and"
(&&) :: Bool -> Bool -> Bool
infixr 3 &&

-- | Boolean "or"
(||) :: Bool -> Bool -> Bool
infixr 2 ||

-- | Boolean "not"
not :: Bool -> Bool

-- | Strict (call-by-value) application operator. It takes a function and
--   an argument, evaluates the argument to weak head normal form (WHNF),
--   then calls the function with that value.
($!) :: () => a -> b -> a -> b
infixr 0 $!

-- | Send the first component of the input through the argument arrow, and
--   copy the rest unchanged to the output.
first :: Arrow a => a b c -> a (b, d) (c, d)

-- | A mirror image of <a>first</a>.
--   
--   The default definition may be overridden with a more efficient version
--   if desired.
second :: Arrow a => a b c -> a (d, b) (d, c)

-- | Split the input between the two argument arrows and combine their
--   output. Note that this is in general not a functor.
--   
--   The default definition may be overridden with a more efficient version
--   if desired.
(***) :: Arrow a => a b c -> a b' c' -> a (b, b') (c, c')
infixr 3 ***

-- | Fanout: send the input to both argument arrows and combine their
--   output.
--   
--   The default definition may be overridden with a more efficient version
--   if desired.
(&&&) :: Arrow a => a b c -> a b c' -> a b (c, c')
infixr 3 &&&

-- | Fanin: Split the input between the two argument arrows and merge their
--   outputs.
--   
--   The default definition may be overridden with a more efficient version
--   if desired.
(|||) :: ArrowChoice a => a b d -> a c d -> a Either b c d
infixr 2 |||

-- | Split the input between the two argument arrows, retagging and merging
--   their outputs. Note that this is in general not a functor.
--   
--   The default definition may be overridden with a more efficient version
--   if desired.
(+++) :: ArrowChoice a => a b c -> a b' c' -> a Either b b' Either c c'
infixr 2 +++

-- | The <a>join</a> function is the conventional monad join operator. It
--   is used to remove one level of monadic structure, projecting its bound
--   argument into the outer level.
join :: Monad m => m m a -> m a

-- | The <a>Monad</a> class defines the basic operations over a
--   <i>monad</i>, a concept from a branch of mathematics known as
--   <i>category theory</i>. From the perspective of a Haskell programmer,
--   however, it is best to think of a monad as an <i>abstract datatype</i>
--   of actions. Haskell's <tt>do</tt> expressions provide a convenient
--   syntax for writing monadic expressions.
--   
--   Instances of <a>Monad</a> should satisfy the following laws:
--   
--   <ul>
--   <li><pre><a>return</a> a <a>&gt;&gt;=</a> k = k a</pre></li>
--   <li><pre>m <a>&gt;&gt;=</a> <a>return</a> = m</pre></li>
--   <li><pre>m <a>&gt;&gt;=</a> (\x -&gt; k x <a>&gt;&gt;=</a> h) = (m
--   <a>&gt;&gt;=</a> k) <a>&gt;&gt;=</a> h</pre></li>
--   </ul>
--   
--   Furthermore, the <a>Monad</a> and <a>Applicative</a> operations should
--   relate as follows:
--   
--   <ul>
--   <li><pre><a>pure</a> = <a>return</a></pre></li>
--   <li><pre>(<a>&lt;*&gt;</a>) = <a>ap</a></pre></li>
--   </ul>
--   
--   The above laws imply:
--   
--   <ul>
--   <li><pre><a>fmap</a> f xs = xs <a>&gt;&gt;=</a> <a>return</a> .
--   f</pre></li>
--   <li><pre>(<a>&gt;&gt;</a>) = (<a>*&gt;</a>)</pre></li>
--   </ul>
--   
--   and that <a>pure</a> and (<a>&lt;*&gt;</a>) satisfy the applicative
--   functor laws.
--   
--   The instances of <a>Monad</a> for lists, <a>Maybe</a> and <a>IO</a>
--   defined in the <a>Prelude</a> satisfy these laws.
class Applicative m => Monad (m :: * -> *)

-- | Sequentially compose two actions, passing any value produced by the
--   first as an argument to the second.
(>>=) :: Monad m => m a -> a -> m b -> m b

-- | Sequentially compose two actions, discarding any value produced by the
--   first, like sequencing operators (such as the semicolon) in imperative
--   languages.
(>>) :: Monad m => m a -> m b -> m b

-- | Inject a value into the monadic type.
return :: Monad m => a -> m a

-- | Fail with a message. This operation is not part of the mathematical
--   definition of a monad, but is invoked on pattern-match failure in a
--   <tt>do</tt> expression.
--   
--   As part of the MonadFail proposal (MFP), this function is moved to its
--   own class <tt>MonadFail</tt> (see <a>Control.Monad.Fail</a> for more
--   details). The definition here will be removed in a future release.
fail :: Monad m => String -> m a

-- | The <a>Functor</a> class is used for types that can be mapped over.
--   Instances of <a>Functor</a> should satisfy the following laws:
--   
--   <pre>
--   fmap id  ==  id
--   fmap (f . g)  ==  fmap f . fmap g
--   </pre>
--   
--   The instances of <a>Functor</a> for lists, <a>Maybe</a> and <a>IO</a>
--   satisfy these laws.
class Functor (f :: * -> *)
fmap :: Functor f => a -> b -> f a -> f b

-- | Map each element of a structure to a monadic action, evaluate these
--   actions from left to right, and collect the results. For a version
--   that ignores the results see <a>mapM_</a>.
mapM :: (Traversable t, Monad m) => a -> m b -> t a -> m t b

-- | Evaluate each monadic action in the structure from left to right, and
--   collect the results. For a version that ignores the results see
--   <a>sequence_</a>.
sequence :: (Traversable t, Monad m) => t m a -> m t a

-- | Monads that also support choice and failure.
class (Alternative m, Monad m) => MonadPlus (m :: * -> *)

-- | The identity of <a>mplus</a>. It should also satisfy the equations
--   
--   <pre>
--   mzero &gt;&gt;= f  =  mzero
--   v &gt;&gt; mzero   =  mzero
--   </pre>
--   
--   The default definition is
--   
--   <pre>
--   mzero = <a>empty</a>
--   </pre>
mzero :: MonadPlus m => m a

-- | An associative operation. The default definition is
--   
--   <pre>
--   mplus = (<a>&lt;|&gt;</a>)
--   </pre>
mplus :: MonadPlus m => m a -> m a -> m a

-- | Direct <a>MonadPlus</a> equivalent of <tt>filter</tt>
--   <tt><tt>filter</tt></tt> = <tt>(mfilter:: (a -&gt; Bool) -&gt; [a]
--   -&gt; [a]</tt> applicable to any <a>MonadPlus</a>, for example
--   <tt>mfilter odd (Just 1) == Just 1</tt> <tt>mfilter odd (Just 2) ==
--   Nothing</tt>
mfilter :: MonadPlus m => a -> Bool -> m a -> m a

-- | Strict version of <a>&lt;$&gt;</a>.
(<$!>) :: Monad m => a -> b -> m a -> m b
infixl 4 <$!>

-- | The reverse of <a>when</a>.
unless :: Applicative f => Bool -> f () -> f ()

-- | Like <a>replicateM</a>, but discards the result.
replicateM_ :: Applicative m => Int -> m a -> m ()

-- | <tt><a>replicateM</a> n act</tt> performs the action <tt>n</tt> times,
--   gathering the results.
replicateM :: Applicative m => Int -> m a -> m [a]

-- | Like <a>foldM</a>, but discards the result.
foldM_ :: (Foldable t, Monad m) => b -> a -> m b -> b -> t a -> m ()

-- | The <a>foldM</a> function is analogous to <tt>foldl</tt>, except that
--   its result is encapsulated in a monad. Note that <a>foldM</a> works
--   from left-to-right over the list arguments. This could be an issue
--   where <tt>(<a>&gt;&gt;</a>)</tt> and the `folded function' are not
--   commutative.
--   
--   <pre>
--   foldM f a1 [x1, x2, ..., xm]
--   
--   ==
--   
--   do
--     a2 &lt;- f a1 x1
--     a3 &lt;- f a2 x2
--     ...
--     f am xm
--   </pre>
--   
--   If right-to-left evaluation is required, the input list should be
--   reversed.
--   
--   Note: <a>foldM</a> is the same as <a>foldlM</a>
foldM :: (Foldable t, Monad m) => b -> a -> m b -> b -> t a -> m b

-- | <a>zipWithM_</a> is the extension of <a>zipWithM</a> which ignores the
--   final result.
zipWithM_ :: Applicative m => a -> b -> m c -> [a] -> [b] -> m ()

-- | The <a>zipWithM</a> function generalizes <a>zipWith</a> to arbitrary
--   applicative functors.
zipWithM :: Applicative m => a -> b -> m c -> [a] -> [b] -> m [c]

-- | The <a>mapAndUnzipM</a> function maps its first argument over a list,
--   returning the result as a pair of lists. This function is mainly used
--   with complicated data structures or a state-transforming monad.
mapAndUnzipM :: Applicative m => a -> m (b, c) -> [a] -> m ([b], [c])

-- | <tt><a>forever</a> act</tt> repeats the action infinitely.
forever :: Applicative f => f a -> f b

-- | Right-to-left Kleisli composition of monads.
--   <tt>(<a>&gt;=&gt;</a>)</tt>, with the arguments flipped.
--   
--   Note how this operator resembles function composition
--   <tt>(<a>.</a>)</tt>:
--   
--   <pre>
--   (.)   ::            (b -&gt;   c) -&gt; (a -&gt;   b) -&gt; a -&gt;   c
--   (&lt;=&lt;) :: Monad m =&gt; (b -&gt; m c) -&gt; (a -&gt; m b) -&gt; a -&gt; m c
--   </pre>
(<=<) :: Monad m => b -> m c -> a -> m b -> a -> m c
infixr 1 <=<

-- | Left-to-right Kleisli composition of monads.
(>=>) :: Monad m => a -> m b -> b -> m c -> a -> m c
infixr 1 >=>

-- | This generalizes the list-based <tt>filter</tt> function.
filterM :: Applicative m => a -> m Bool -> [a] -> m [a]

-- | <a>forM</a> is <a>mapM</a> with its arguments flipped. For a version
--   that ignores the results see <a>forM_</a>.
forM :: (Traversable t, Monad m) => t a -> a -> m b -> m t b

-- | The sum of a collection of actions, generalizing <a>concat</a>. As of
--   base 4.8.0.0, <a>msum</a> is just <a>asum</a>, specialized to
--   <a>MonadPlus</a>.
msum :: (Foldable t, MonadPlus m) => t m a -> m a

-- | Evaluate each monadic action in the structure from left to right, and
--   ignore the results. For a version that doesn't ignore the results see
--   <a>sequence</a>.
--   
--   As of base 4.8.0.0, <a>sequence_</a> is just <a>sequenceA_</a>,
--   specialized to <a>Monad</a>.
sequence_ :: (Foldable t, Monad m) => t m a -> m ()

-- | <a>forM_</a> is <a>mapM_</a> with its arguments flipped. For a version
--   that doesn't ignore the results see <a>forM</a>.
--   
--   As of base 4.8.0.0, <a>forM_</a> is just <a>for_</a>, specialized to
--   <a>Monad</a>.
forM_ :: (Foldable t, Monad m) => t a -> a -> m b -> m ()

-- | Map each element of a structure to a monadic action, evaluate these
--   actions from left to right, and ignore the results. For a version that
--   doesn't ignore the results see <a>mapM</a>.
--   
--   As of base 4.8.0.0, <a>mapM_</a> is just <a>traverse_</a>, specialized
--   to <a>Monad</a>.
mapM_ :: (Foldable t, Monad m) => a -> m b -> t a -> m ()

-- | <tt><a>void</a> value</tt> discards or ignores the result of
--   evaluation, such as the return value of an <a>IO</a> action.
--   
--   <h4><b>Examples</b></h4>
--   
--   Replace the contents of a <tt><tt>Maybe</tt> <tt>Int</tt></tt> with
--   unit:
--   
--   <pre>
--   &gt;&gt;&gt; void Nothing
--   Nothing
--   
--   &gt;&gt;&gt; void (Just 3)
--   Just ()
--   </pre>
--   
--   Replace the contents of an <tt><tt>Either</tt> <tt>Int</tt>
--   <tt>Int</tt></tt> with unit, resulting in an <tt><tt>Either</tt>
--   <tt>Int</tt> '()'</tt>:
--   
--   <pre>
--   &gt;&gt;&gt; void (Left 8675309)
--   Left 8675309
--   
--   &gt;&gt;&gt; void (Right 8675309)
--   Right ()
--   </pre>
--   
--   Replace every element of a list with unit:
--   
--   <pre>
--   &gt;&gt;&gt; void [1,2,3]
--   [(),(),()]
--   </pre>
--   
--   Replace the second element of a pair with unit:
--   
--   <pre>
--   &gt;&gt;&gt; void (1,2)
--   (1,())
--   </pre>
--   
--   Discard the result of an <a>IO</a> action:
--   
--   <pre>
--   &gt;&gt;&gt; mapM print [1,2]
--   1
--   2
--   [(),()]
--   
--   &gt;&gt;&gt; void $ mapM print [1,2]
--   1
--   2
--   </pre>
void :: Functor f => f a -> f ()

-- | In many situations, the <a>liftM</a> operations can be replaced by
--   uses of <a>ap</a>, which promotes function application.
--   
--   <pre>
--   return f `ap` x1 `ap` ... `ap` xn
--   </pre>
--   
--   is equivalent to
--   
--   <pre>
--   liftMn f x1 x2 ... xn
--   </pre>
ap :: Monad m => m a -> b -> m a -> m b

-- | Promote a function to a monad, scanning the monadic arguments from
--   left to right (cf. <a>liftM2</a>).
liftM5 :: Monad m => a1 -> a2 -> a3 -> a4 -> a5 -> r -> m a1 -> m a2 -> m a3 -> m a4 -> m a5 -> m r

-- | Promote a function to a monad, scanning the monadic arguments from
--   left to right (cf. <a>liftM2</a>).
liftM4 :: Monad m => a1 -> a2 -> a3 -> a4 -> r -> m a1 -> m a2 -> m a3 -> m a4 -> m r

-- | Promote a function to a monad, scanning the monadic arguments from
--   left to right (cf. <a>liftM2</a>).
liftM3 :: Monad m => a1 -> a2 -> a3 -> r -> m a1 -> m a2 -> m a3 -> m r

-- | Promote a function to a monad, scanning the monadic arguments from
--   left to right. For example,
--   
--   <pre>
--   liftM2 (+) [0,1] [0,2] = [0,2,1,3]
--   liftM2 (+) (Just 1) Nothing = Nothing
--   </pre>
liftM2 :: Monad m => a1 -> a2 -> r -> m a1 -> m a2 -> m r

-- | Promote a function to a monad.
liftM :: Monad m => a1 -> r -> m a1 -> m r

-- | Conditional execution of <a>Applicative</a> expressions. For example,
--   
--   <pre>
--   when debug (putStrLn "Debugging")
--   </pre>
--   
--   will output the string <tt>Debugging</tt> if the Boolean value
--   <tt>debug</tt> is <a>True</a>, and otherwise do nothing.
when :: Applicative f => Bool -> f () -> f ()

-- | Same as <a>&gt;&gt;=</a>, but with the arguments interchanged.
(=<<) :: Monad m => a -> m b -> m a -> m b
infixr 1 =<<

-- | The character type <a>Char</a> is an enumeration whose values
--   represent Unicode (or equivalently ISO/IEC 10646) code points (i.e.
--   characters, see <a>http://www.unicode.org/</a> for details). This set
--   extends the ISO 8859-1 (Latin-1) character set (the first 256
--   characters), which is itself an extension of the ASCII character set
--   (the first 128 characters). A character literal in Haskell has type
--   <a>Char</a>.
--   
--   To convert a <a>Char</a> to or from the corresponding <a>Int</a> value
--   defined by Unicode, use <a>toEnum</a> and <a>fromEnum</a> from the
--   <a>Enum</a> class respectively (or equivalently <tt>ord</tt> and
--   <tt>chr</tt>).
data Char

-- | Returns <a>True</a> for any Unicode space character, and the control
--   characters <tt>\t</tt>, <tt>\n</tt>, <tt>\r</tt>, <tt>\f</tt>,
--   <tt>\v</tt>.
isSpace :: Char -> Bool

-- | Selects alphabetic Unicode characters (lower-case, upper-case and
--   title-case letters, plus letters of caseless scripts and modifiers
--   letters). This function is equivalent to <a>isLetter</a>.
isAlpha :: Char -> Bool

-- | Selects ASCII digits, i.e. <tt>'0'</tt>..<tt>'9'</tt>.
isDigit :: Char -> Bool

-- | Selects Unicode space and separator characters.
--   
--   This function returns <a>True</a> if its argument has one of the
--   following <a>GeneralCategory</a>s, or <a>False</a> otherwise:
--   
--   <ul>
--   <li><a>Space</a></li>
--   <li><a>LineSeparator</a></li>
--   <li><a>ParagraphSeparator</a></li>
--   </ul>
--   
--   These classes are defined in the <a>Unicode Character Database</a>,
--   part of the Unicode standard. The same document defines what is and is
--   not a "Separator".
--   
--   <h4><b>Examples</b></h4>
--   
--   Basic usage:
--   
--   <pre>
--   &gt;&gt;&gt; isSeparator 'a'
--   False
--   
--   &gt;&gt;&gt; isSeparator '6'
--   False
--   
--   &gt;&gt;&gt; isSeparator ' '
--   True
--   </pre>
--   
--   Warning: newlines and tab characters are not considered separators.
--   
--   <pre>
--   &gt;&gt;&gt; isSeparator '\n'
--   False
--   
--   &gt;&gt;&gt; isSeparator '\t'
--   False
--   </pre>
--   
--   But some more exotic characters are (like HTML's <tt>&amp;nbsp;</tt>):
--   
--   <pre>
--   &gt;&gt;&gt; isSeparator '\160'
--   True
--   </pre>
isSeparator :: Char -> Bool

-- | Selects Unicode numeric characters, including digits from various
--   scripts, Roman numerals, et cetera.
--   
--   This function returns <a>True</a> if its argument has one of the
--   following <a>GeneralCategory</a>s, or <a>False</a> otherwise:
--   
--   <ul>
--   <li><a>DecimalNumber</a></li>
--   <li><a>LetterNumber</a></li>
--   <li><a>OtherNumber</a></li>
--   </ul>
--   
--   These classes are defined in the <a>Unicode Character Database</a>,
--   part of the Unicode standard. The same document defines what is and is
--   not a "Number".
--   
--   <h4><b>Examples</b></h4>
--   
--   Basic usage:
--   
--   <pre>
--   &gt;&gt;&gt; isNumber 'a'
--   False
--   
--   &gt;&gt;&gt; isNumber '%'
--   False
--   
--   &gt;&gt;&gt; isNumber '3'
--   True
--   </pre>
--   
--   ASCII <tt>'0'</tt> through <tt>'9'</tt> are all numbers:
--   
--   <pre>
--   &gt;&gt;&gt; and $ map isNumber ['0'..'9']
--   True
--   </pre>
--   
--   Unicode Roman numerals are "numbers" as well:
--   
--   <pre>
--   &gt;&gt;&gt; isNumber 'Ⅸ'
--   True
--   </pre>
isNumber :: Char -> Bool

-- | Selects Unicode mark characters, for example accents and the like,
--   which combine with preceding characters.
--   
--   This function returns <a>True</a> if its argument has one of the
--   following <a>GeneralCategory</a>s, or <a>False</a> otherwise:
--   
--   <ul>
--   <li><a>NonSpacingMark</a></li>
--   <li><a>SpacingCombiningMark</a></li>
--   <li><a>EnclosingMark</a></li>
--   </ul>
--   
--   These classes are defined in the <a>Unicode Character Database</a>,
--   part of the Unicode standard. The same document defines what is and is
--   not a "Mark".
--   
--   <h4><b>Examples</b></h4>
--   
--   Basic usage:
--   
--   <pre>
--   &gt;&gt;&gt; isMark 'a'
--   False
--   
--   &gt;&gt;&gt; isMark '0'
--   False
--   </pre>
--   
--   Combining marks such as accent characters usually need to follow
--   another character before they become printable:
--   
--   <pre>
--   &gt;&gt;&gt; map isMark "ò"
--   [False,True]
--   </pre>
--   
--   Puns are not necessarily supported:
--   
--   <pre>
--   &gt;&gt;&gt; isMark '✓'
--   False
--   </pre>
isMark :: Char -> Bool

-- | Selects alphabetic Unicode characters (lower-case, upper-case and
--   title-case letters, plus letters of caseless scripts and modifiers
--   letters). This function is equivalent to <a>isAlpha</a>.
--   
--   This function returns <a>True</a> if its argument has one of the
--   following <a>GeneralCategory</a>s, or <a>False</a> otherwise:
--   
--   <ul>
--   <li><a>UppercaseLetter</a></li>
--   <li><a>LowercaseLetter</a></li>
--   <li><a>TitlecaseLetter</a></li>
--   <li><a>ModifierLetter</a></li>
--   <li><a>OtherLetter</a></li>
--   </ul>
--   
--   These classes are defined in the <a>Unicode Character Database</a>,
--   part of the Unicode standard. The same document defines what is and is
--   not a "Letter".
--   
--   <h4><b>Examples</b></h4>
--   
--   Basic usage:
--   
--   <pre>
--   &gt;&gt;&gt; isLetter 'a'
--   True
--   
--   &gt;&gt;&gt; isLetter 'A'
--   True
--   
--   &gt;&gt;&gt; isLetter 'λ'
--   True
--   
--   &gt;&gt;&gt; isLetter '0'
--   False
--   
--   &gt;&gt;&gt; isLetter '%'
--   False
--   
--   &gt;&gt;&gt; isLetter '♥'
--   False
--   
--   &gt;&gt;&gt; isLetter '\31'
--   False
--   </pre>
--   
--   Ensure that <a>isLetter</a> and <a>isAlpha</a> are equivalent.
--   
--   <pre>
--   &gt;&gt;&gt; let chars = [(chr 0)..]
--   
--   &gt;&gt;&gt; let letters = map isLetter chars
--   
--   &gt;&gt;&gt; let alphas = map isAlpha chars
--   
--   &gt;&gt;&gt; letters == alphas
--   True
--   </pre>
isLetter :: Char -> Bool

-- | Convert a single digit <a>Char</a> to the corresponding <a>Int</a>.
--   This function fails unless its argument satisfies <a>isHexDigit</a>,
--   but recognises both upper- and lower-case hexadecimal digits (that is,
--   <tt>'0'</tt>..<tt>'9'</tt>, <tt>'a'</tt>..<tt>'f'</tt>,
--   <tt>'A'</tt>..<tt>'F'</tt>).
--   
--   <h4><b>Examples</b></h4>
--   
--   Characters <tt>'0'</tt> through <tt>'9'</tt> are converted properly to
--   <tt>0..9</tt>:
--   
--   <pre>
--   &gt;&gt;&gt; map digitToInt ['0'..'9']
--   [0,1,2,3,4,5,6,7,8,9]
--   </pre>
--   
--   Both upper- and lower-case <tt>'A'</tt> through <tt>'F'</tt> are
--   converted as well, to <tt>10..15</tt>.
--   
--   <pre>
--   &gt;&gt;&gt; map digitToInt ['a'..'f']
--   [10,11,12,13,14,15]
--   
--   &gt;&gt;&gt; map digitToInt ['A'..'F']
--   [10,11,12,13,14,15]
--   </pre>
--   
--   Anything else throws an exception:
--   
--   <pre>
--   &gt;&gt;&gt; digitToInt 'G'
--   *** Exception: Char.digitToInt: not a digit 'G'
--   
--   &gt;&gt;&gt; digitToInt '♥'
--   *** Exception: Char.digitToInt: not a digit '\9829'
--   </pre>
digitToInt :: Char -> Int

-- | Read a string representation of a character, using Haskell
--   source-language escape conventions, and convert it to the character
--   that it encodes. For example:
--   
--   <pre>
--   readLitChar "\\nHello"  =  [('\n', "Hello")]
--   </pre>
readLitChar :: ReadS Char

-- | Read a string representation of a character, using Haskell
--   source-language escape conventions. For example:
--   
--   <pre>
--   lexLitChar  "\\nHello"  =  [("\\n", "Hello")]
--   </pre>
lexLitChar :: ReadS String

-- | Convert a letter to the corresponding title-case or upper-case letter,
--   if any. (Title case differs from upper case only for a small number of
--   ligature letters.) Any other character is returned unchanged.
toTitle :: Char -> Char

-- | Convert a letter to the corresponding upper-case letter, if any. Any
--   other character is returned unchanged.
toUpper :: Char -> Char

-- | Convert a letter to the corresponding lower-case letter, if any. Any
--   other character is returned unchanged.
toLower :: Char -> Char

-- | Selects lower-case alphabetic Unicode characters (letters).
isLower :: Char -> Bool

-- | Selects upper-case or title-case alphabetic Unicode characters
--   (letters). Title case is used by a small number of letter ligatures
--   like the single-character form of <i>Lj</i>.
isUpper :: Char -> Bool

-- | Selects printable Unicode characters (letters, numbers, marks,
--   punctuation, symbols and spaces).
isPrint :: Char -> Bool

-- | Selects control characters, which are the non-printing characters of
--   the Latin-1 subset of Unicode.
isControl :: Char -> Bool

-- | Selects alphabetic or numeric digit Unicode characters.
--   
--   Note that numeric digits outside the ASCII range are selected by this
--   function but not by <a>isDigit</a>. Such digits may be part of
--   identifiers but are not used by the printer and reader to represent
--   numbers.
isAlphaNum :: Char -> Bool

-- | Selects Unicode symbol characters, including mathematical and currency
--   symbols.
--   
--   This function returns <a>True</a> if its argument has one of the
--   following <a>GeneralCategory</a>s, or <a>False</a> otherwise:
--   
--   <ul>
--   <li><a>MathSymbol</a></li>
--   <li><a>CurrencySymbol</a></li>
--   <li><a>ModifierSymbol</a></li>
--   <li><a>OtherSymbol</a></li>
--   </ul>
--   
--   These classes are defined in the <a>Unicode Character Database</a>,
--   part of the Unicode standard. The same document defines what is and is
--   not a "Symbol".
--   
--   <h4><b>Examples</b></h4>
--   
--   Basic usage:
--   
--   <pre>
--   &gt;&gt;&gt; isSymbol 'a'
--   False
--   
--   &gt;&gt;&gt; isSymbol '6'
--   False
--   
--   &gt;&gt;&gt; isSymbol '='
--   True
--   </pre>
--   
--   The definition of "math symbol" may be a little counter-intuitive
--   depending on one's background:
--   
--   <pre>
--   &gt;&gt;&gt; isSymbol '+'
--   True
--   
--   &gt;&gt;&gt; isSymbol '-'
--   False
--   </pre>
isSymbol :: Char -> Bool

-- | Selects Unicode punctuation characters, including various kinds of
--   connectors, brackets and quotes.
--   
--   This function returns <a>True</a> if its argument has one of the
--   following <a>GeneralCategory</a>s, or <a>False</a> otherwise:
--   
--   <ul>
--   <li><a>ConnectorPunctuation</a></li>
--   <li><a>DashPunctuation</a></li>
--   <li><a>OpenPunctuation</a></li>
--   <li><a>ClosePunctuation</a></li>
--   <li><a>InitialQuote</a></li>
--   <li><a>FinalQuote</a></li>
--   <li><a>OtherPunctuation</a></li>
--   </ul>
--   
--   These classes are defined in the <a>Unicode Character Database</a>,
--   part of the Unicode standard. The same document defines what is and is
--   not a "Punctuation".
--   
--   <h4><b>Examples</b></h4>
--   
--   Basic usage:
--   
--   <pre>
--   &gt;&gt;&gt; isPunctuation 'a'
--   False
--   
--   &gt;&gt;&gt; isPunctuation '7'
--   False
--   
--   &gt;&gt;&gt; isPunctuation '♥'
--   False
--   
--   &gt;&gt;&gt; isPunctuation '"'
--   True
--   
--   &gt;&gt;&gt; isPunctuation '?'
--   True
--   
--   &gt;&gt;&gt; isPunctuation '—'
--   True
--   </pre>
isPunctuation :: Char -> Bool

-- | Selects ASCII hexadecimal digits, i.e. <tt>'0'</tt>..<tt>'9'</tt>,
--   <tt>'a'</tt>..<tt>'f'</tt>, <tt>'A'</tt>..<tt>'F'</tt>.
isHexDigit :: Char -> Bool

-- | Selects ASCII octal digits, i.e. <tt>'0'</tt>..<tt>'7'</tt>.
isOctDigit :: Char -> Bool

-- | Selects ASCII upper-case letters, i.e. characters satisfying both
--   <a>isAscii</a> and <a>isUpper</a>.
isAsciiUpper :: Char -> Bool

-- | Selects ASCII lower-case letters, i.e. characters satisfying both
--   <a>isAscii</a> and <a>isLower</a>.
isAsciiLower :: Char -> Bool

-- | Selects the first 256 characters of the Unicode character set,
--   corresponding to the ISO 8859-1 (Latin-1) character set.
isLatin1 :: Char -> Bool

-- | Selects the first 128 characters of the Unicode character set,
--   corresponding to the ASCII character set.
isAscii :: Char -> Bool

-- | The Unicode general category of the character. This relies on the
--   <a>Enum</a> instance of <a>GeneralCategory</a>, which must remain in
--   the same order as the categories are presented in the Unicode
--   standard.
--   
--   <h4><b>Examples</b></h4>
--   
--   Basic usage:
--   
--   <pre>
--   &gt;&gt;&gt; generalCategory 'a'
--   LowercaseLetter
--   
--   &gt;&gt;&gt; generalCategory 'A'
--   UppercaseLetter
--   
--   &gt;&gt;&gt; generalCategory '0'
--   DecimalNumber
--   
--   &gt;&gt;&gt; generalCategory '%'
--   OtherPunctuation
--   
--   &gt;&gt;&gt; generalCategory '♥'
--   OtherSymbol
--   
--   &gt;&gt;&gt; generalCategory '\31'
--   Control
--   
--   &gt;&gt;&gt; generalCategory ' '
--   Space
--   </pre>
generalCategory :: Char -> GeneralCategory

-- | The <a>toEnum</a> method restricted to the type <a>Char</a>.
chr :: Int -> Char

-- | Convert an <a>Int</a> in the range <tt>0</tt>..<tt>15</tt> to the
--   corresponding single digit <a>Char</a>. This function fails on other
--   inputs, and generates lower-case hexadecimal digits.
intToDigit :: Int -> Char

-- | Convert a character to a string using only printable characters, using
--   Haskell source-language escape conventions. For example:
--   
--   <pre>
--   showLitChar '\n' s  =  "\\n" ++ s
--   </pre>
showLitChar :: Char -> ShowS

-- | The <a>fromEnum</a> method restricted to the type <a>Char</a>.
ord :: Char -> Int

-- | The <a>Data</a> class comprehends a fundamental primitive
--   <a>gfoldl</a> for folding over constructor applications, say terms.
--   This primitive can be instantiated in several ways to map over the
--   immediate subterms of a term; see the <tt>gmap</tt> combinators later
--   in this class. Indeed, a generic programmer does not necessarily need
--   to use the ingenious gfoldl primitive but rather the intuitive
--   <tt>gmap</tt> combinators. The <a>gfoldl</a> primitive is completed by
--   means to query top-level constructors, to turn constructor
--   representations into proper terms, and to list all possible datatype
--   constructors. This completion allows us to serve generic programming
--   scenarios like read, show, equality, term generation.
--   
--   The combinators <a>gmapT</a>, <a>gmapQ</a>, <a>gmapM</a>, etc are all
--   provided with default definitions in terms of <a>gfoldl</a>, leaving
--   open the opportunity to provide datatype-specific definitions. (The
--   inclusion of the <tt>gmap</tt> combinators as members of class
--   <a>Data</a> allows the programmer or the compiler to derive
--   specialised, and maybe more efficient code per datatype. <i>Note</i>:
--   <a>gfoldl</a> is more higher-order than the <tt>gmap</tt> combinators.
--   This is subject to ongoing benchmarking experiments. It might turn out
--   that the <tt>gmap</tt> combinators will be moved out of the class
--   <a>Data</a>.)
--   
--   Conceptually, the definition of the <tt>gmap</tt> combinators in terms
--   of the primitive <a>gfoldl</a> requires the identification of the
--   <a>gfoldl</a> function arguments. Technically, we also need to
--   identify the type constructor <tt>c</tt> for the construction of the
--   result type from the folded term type.
--   
--   In the definition of <tt>gmapQ</tt><i>x</i> combinators, we use
--   phantom type constructors for the <tt>c</tt> in the type of
--   <a>gfoldl</a> because the result type of a query does not involve the
--   (polymorphic) type of the term argument. In the definition of
--   <a>gmapQl</a> we simply use the plain constant type constructor
--   because <a>gfoldl</a> is left-associative anyway and so it is readily
--   suited to fold a left-associative binary operation over the immediate
--   subterms. In the definition of gmapQr, extra effort is needed. We use
--   a higher-order accumulation trick to mediate between left-associative
--   constructor application vs. right-associative binary operation (e.g.,
--   <tt>(:)</tt>). When the query is meant to compute a value of type
--   <tt>r</tt>, then the result type withing generic folding is <tt>r
--   -&gt; r</tt>. So the result of folding is a function to which we
--   finally pass the right unit.
--   
--   With the <tt>-XDeriveDataTypeable</tt> option, GHC can generate
--   instances of the <a>Data</a> class automatically. For example, given
--   the declaration
--   
--   <pre>
--   data T a b = C1 a b | C2 deriving (Typeable, Data)
--   </pre>
--   
--   GHC will generate an instance that is equivalent to
--   
--   <pre>
--   instance (Data a, Data b) =&gt; Data (T a b) where
--       gfoldl k z (C1 a b) = z C1 `k` a `k` b
--       gfoldl k z C2       = z C2
--   
--       gunfold k z c = case constrIndex c of
--                           1 -&gt; k (k (z C1))
--                           2 -&gt; z C2
--   
--       toConstr (C1 _ _) = con_C1
--       toConstr C2       = con_C2
--   
--       dataTypeOf _ = ty_T
--   
--   con_C1 = mkConstr ty_T "C1" [] Prefix
--   con_C2 = mkConstr ty_T "C2" [] Prefix
--   ty_T   = mkDataType "Module.T" [con_C1, con_C2]
--   </pre>
--   
--   This is suitable for datatypes that are exported transparently.
class Typeable a => Data a

-- | Left-associative fold operation for constructor applications.
--   
--   The type of <a>gfoldl</a> is a headache, but operationally it is a
--   simple generalisation of a list fold.
--   
--   The default definition for <a>gfoldl</a> is <tt><a>const</a>
--   <a>id</a></tt>, which is suitable for abstract datatypes with no
--   substructures.
gfoldl :: Data a => forall d b. Data d => c d -> b -> d -> c b -> forall g. () => g -> c g -> a -> c a

-- | Unfolding constructor applications
gunfold :: Data a => forall b r. Data b => c b -> r -> c r -> forall r. () => r -> c r -> Constr -> c a

-- | Obtaining the constructor from a given datum. For proper terms, this
--   is meant to be the top-level constructor. Primitive datatypes are here
--   viewed as potentially infinite sets of values (i.e., constructors).
toConstr :: Data a => a -> Constr

-- | The outer type constructor of the type
dataTypeOf :: Data a => a -> DataType

-- | Mediate types and unary type constructors.
--   
--   In <a>Data</a> instances of the form
--   
--   <pre>
--   instance (Data a, ...) =&gt; Data (T a)
--   </pre>
--   
--   <a>dataCast1</a> should be defined as <a>gcast1</a>.
--   
--   The default definition is <tt><a>const</a> <a>Nothing</a></tt>, which
--   is appropriate for instances of other forms.
dataCast1 :: (Data a, Typeable t) => forall d. Data d => c t d -> Maybe c a

-- | Mediate types and binary type constructors.
--   
--   In <a>Data</a> instances of the form
--   
--   <pre>
--   instance (Data a, Data b, ...) =&gt; Data (T a b)
--   </pre>
--   
--   <a>dataCast2</a> should be defined as <a>gcast2</a>.
--   
--   The default definition is <tt><a>const</a> <a>Nothing</a></tt>, which
--   is appropriate for instances of other forms.
dataCast2 :: (Data a, Typeable t) => forall d e. (Data d, Data e) => c t d e -> Maybe c a

-- | A generic transformation that maps over the immediate subterms
--   
--   The default definition instantiates the type constructor <tt>c</tt> in
--   the type of <a>gfoldl</a> to an identity datatype constructor, using
--   the isomorphism pair as injection and projection.
gmapT :: Data a => forall b. Data b => b -> b -> a -> a

-- | A generic query with a left-associative binary operator
gmapQl :: Data a => r -> r' -> r -> r -> forall d. Data d => d -> r' -> a -> r

-- | A generic query with a right-associative binary operator
gmapQr :: Data a => r' -> r -> r -> r -> forall d. Data d => d -> r' -> a -> r

-- | A generic query that processes the immediate subterms and returns a
--   list of results. The list is given in the same order as originally
--   specified in the declaration of the data constructors.
gmapQ :: Data a => forall d. Data d => d -> u -> a -> [u]

-- | A generic query that processes one child by index (zero-based)
gmapQi :: Data a => Int -> forall d. Data d => d -> u -> a -> u

-- | A generic monadic transformation that maps over the immediate subterms
--   
--   The default definition instantiates the type constructor <tt>c</tt> in
--   the type of <a>gfoldl</a> to the monad datatype constructor, defining
--   injection and projection using <a>return</a> and <a>&gt;&gt;=</a>.
gmapM :: (Data a, Monad m) => forall d. Data d => d -> m d -> a -> m a

-- | Transformation of at least one immediate subterm does not fail
gmapMp :: (Data a, MonadPlus m) => forall d. Data d => d -> m d -> a -> m a

-- | Transformation of one immediate subterm with success
gmapMo :: (Data a, MonadPlus m) => forall d. Data d => d -> m d -> a -> m a

-- | The class <a>Typeable</a> allows a concrete representation of a type
--   to be calculated.
class Typeable (a :: k)
on :: () => b -> b -> c -> a -> b -> a -> a -> c
infixl 0 `on`

-- | The class of monoids (types with an associative binary operation that
--   has an identity). Instances should satisfy the following laws:
--   
--   <ul>
--   <li><pre>x <a>&lt;&gt;</a> <a>mempty</a> = x</pre></li>
--   <li><pre><a>mempty</a> <a>&lt;&gt;</a> x = x</pre></li>
--   <li><tt>x <a>&lt;&gt;</a> (y <a>&lt;&gt;</a> z) = (x <a>&lt;&gt;</a>
--   y) <a>&lt;&gt;</a> z</tt> (<a>Semigroup</a> law)</li>
--   <li><pre><a>mconcat</a> = <a>foldr</a> '(&lt;&gt;)'
--   <a>mempty</a></pre></li>
--   </ul>
--   
--   The method names refer to the monoid of lists under concatenation, but
--   there are many other instances.
--   
--   Some types can be viewed as a monoid in more than one way, e.g. both
--   addition and multiplication on numbers. In such cases we often define
--   <tt>newtype</tt>s and make those instances of <a>Monoid</a>, e.g.
--   <tt>Sum</tt> and <tt>Product</tt>.
--   
--   <b>NOTE</b>: <a>Semigroup</a> is a superclass of <a>Monoid</a> since
--   <i>base-4.11.0.0</i>.
class Semigroup a => Monoid a

-- | Identity of <a>mappend</a>
mempty :: Monoid a => a

-- | An associative operation
--   
--   <b>NOTE</b>: This method is redundant and has the default
--   implementation <tt><a>mappend</a> = '(&lt;&gt;)'</tt> since
--   <i>base-4.11.0.0</i>.
mappend :: Monoid a => a -> a -> a

-- | Fold a list using the monoid.
--   
--   For most types, the default definition for <a>mconcat</a> will be
--   used, but the function is included in the class definition so that an
--   optimized version can be provided for specific types.
mconcat :: Monoid a => [a] -> a

-- | Do any of the (monadic) predicates match?
anyM :: (Functor m, Applicative m, Monad m) => (a -> m Bool) -> [a] -> m Bool

-- | Alias of liftIO, I hate typing it. Hate reading it.
io :: MonadIO m => IO a -> m a

-- | Read from a process returning both std err and out.
readAllFromProcess :: FilePath -> [String] -> String -> IO (Either (String, String) (String, String))


-- | Configuring the compiler
module Fay.Config

-- | Configuration of the compiler. The fields with a leading underscore
data Config
defaultConfig :: Config
defaultConfigWithSandbox :: IO Config

-- | Reading _configDirectoryIncludes is safe to do.
configDirectoryIncludes :: Config -> [(Maybe String, FilePath)]

-- | Get all include directories without the package mapping.
configDirectoryIncludePaths :: Config -> [FilePath]

-- | Get all include directories not included through packages.
nonPackageConfigDirectoryIncludePaths :: Config -> [FilePath]

-- | Add a mapping from (maybe) a package to a source directory
addConfigDirectoryInclude :: Maybe String -> FilePath -> Config -> Config

-- | Add several include directories.
addConfigDirectoryIncludes :: [(Maybe String, FilePath)] -> Config -> Config

-- | Add several include directories without package references.
addConfigDirectoryIncludePaths :: [FilePath] -> Config -> Config

-- | Reading _configPackages is safe to do.
configPackages :: Config -> [String]

-- | Add a package to compilation
addConfigPackage :: String -> Config -> Config

-- | Add several packages to compilation
addConfigPackages :: [String] -> Config -> Config

-- | Should a strict wrapper be generated for this module?
shouldExportStrictWrapper :: ModuleName a -> Config -> Bool
instance GHC.Show.Show Fay.Config.Config
instance Data.Default.Class.Default Fay.Config.Config


-- | Convert a Haskell value to a (JSON representation of a) Fay value.
module Fay.Convert

-- | Convert a Haskell value to a Fay json value. This can fail when
--   primitive values aren't handled by explicit cases. <a>encodeFay</a>
--   can be used to resolve this issue.
showToFay :: Data a => a -> Maybe Value

-- | Convert a Fay json value to a Haskell value.
readFromFay :: Data a => Value -> Maybe a

-- | Convert a Fay json value to a Haskell value. This is like readFromFay,
--   except it yields helpful error messages on failure.
readFromFay' :: Data a => Value -> Either String a

-- | Convert a Haskell value to a Fay json value. This can fail when
--   primitive values aren't handled by explicit cases. When this happens,
--   you can add additional cases via the first parameter.
--   
--   The first parameter is a function that can be used to override the
--   conversion. This usually looks like using <a>extQ</a> to additional
--   type- specific cases.
encodeFay :: (GenericQ Value -> GenericQ Value) -> GenericQ Value

-- | Convert a Fay json value to a Haskell value.
--   
--   The first parameter is a function that can be used to override the
--   conversion. This usually looks like using <a>extR</a> to additional
--   type- specific cases.
decodeFay :: Data b => (forall a. Data a => Value -> Either String a -> Either String a) -> Value -> Either String b

module Fay.Types.CompileResult
data CompileResult
CompileResult :: String -> [(String, FilePath)] -> Maybe [Mapping] -> CompileResult
[resOutput] :: CompileResult -> String
[resImported] :: CompileResult -> [(String, FilePath)]
[resSourceMappings] :: CompileResult -> Maybe [Mapping]
instance GHC.Show.Show Fay.Types.CompileResult.CompileResult

module Fay.Types.CompileError

-- | Error type.
data CompileError
Couldn'tFindImport :: ModuleName -> [FilePath] -> CompileError
EmptyDoBlock :: CompileError
FfiFormatBadChars :: SrcSpanInfo -> String -> CompileError
FfiFormatIncompleteArg :: SrcSpanInfo -> CompileError
FfiFormatInvalidJavaScript :: SrcSpanInfo -> String -> String -> CompileError
FfiFormatNoSuchArg :: SrcSpanInfo -> Int -> CompileError
FfiNeedsTypeSig :: Exp -> CompileError
GHCError :: String -> CompileError
InvalidDoBlock :: CompileError
ParseError :: SrcLoc -> String -> CompileError
ShouldBeDesugared :: String -> CompileError
UnableResolveQualified :: QName -> CompileError
UnsupportedDeclaration :: Decl -> CompileError
UnsupportedEnum :: Exp -> CompileError
UnsupportedExportSpec :: ExportSpec -> CompileError
UnsupportedExpression :: Exp -> CompileError
UnsupportedFieldPattern :: PatField -> CompileError
UnsupportedImport :: ImportDecl -> CompileError
UnsupportedLet :: CompileError
UnsupportedLetBinding :: Decl -> CompileError
UnsupportedLiteral :: Literal -> CompileError
UnsupportedModuleSyntax :: String -> Module -> CompileError
UnsupportedPattern :: Pat -> CompileError
UnsupportedQualStmt :: QualStmt -> CompileError
UnsupportedRecursiveDo :: CompileError
UnsupportedRhs :: Rhs -> CompileError
UnsupportedWhereInAlt :: Alt -> CompileError
UnsupportedWhereInMatch :: Match -> CompileError
instance GHC.Show.Show Fay.Types.CompileError.CompileError


-- | All Fay types and instances.
module Fay.Types

-- | Statement type.
data JsStmt
JsVar :: JsName -> JsExp -> JsStmt
JsMapVar :: JsName -> JsExp -> JsStmt
JsIf :: JsExp -> [JsStmt] -> [JsStmt] -> JsStmt
JsEarlyReturn :: JsExp -> JsStmt
JsThrow :: JsExp -> JsStmt
JsWhile :: JsExp -> [JsStmt] -> JsStmt
JsUpdate :: JsName -> JsExp -> JsStmt
JsSetProp :: JsName -> JsName -> JsExp -> JsStmt
JsSetQName :: (Maybe SrcSpan) -> QName -> JsExp -> JsStmt
JsSetModule :: ModulePath -> JsExp -> JsStmt
JsSetConstructor :: QName -> JsExp -> JsStmt
JsSetPropExtern :: JsName -> JsName -> JsExp -> JsStmt
JsContinue :: JsStmt
JsBlock :: [JsStmt] -> JsStmt
JsExpStmt :: JsExp -> JsStmt

-- | Expression type.
data JsExp
JsName :: JsName -> JsExp
JsRawExp :: String -> JsExp
JsSeq :: [JsExp] -> JsExp
JsFun :: (Maybe JsName) -> [JsName] -> [JsStmt] -> (Maybe JsExp) -> JsExp
JsLit :: JsLit -> JsExp
JsApp :: JsExp -> [JsExp] -> JsExp
JsNegApp :: JsExp -> JsExp
JsTernaryIf :: JsExp -> JsExp -> JsExp -> JsExp
JsNull :: JsExp
JsParen :: JsExp -> JsExp
JsGetProp :: JsExp -> JsName -> JsExp
JsLookup :: JsExp -> JsExp -> JsExp
JsUpdateProp :: JsExp -> JsName -> JsExp -> JsExp
JsGetPropExtern :: JsExp -> String -> JsExp
JsUpdatePropExtern :: JsExp -> JsName -> JsExp -> JsExp
JsList :: [JsExp] -> JsExp
JsNew :: JsName -> [JsExp] -> JsExp
JsThrowExp :: JsExp -> JsExp
JsInstanceOf :: JsExp -> JsName -> JsExp
JsIndex :: Int -> JsExp -> JsExp
JsEq :: JsExp -> JsExp -> JsExp
JsNeq :: JsExp -> JsExp -> JsExp
JsInfix :: String -> JsExp -> JsExp -> JsExp
JsObj :: [(String, JsExp)] -> JsExp
JsLitObj :: [(Name, JsExp)] -> JsExp
JsUndefined :: JsExp
JsAnd :: JsExp -> JsExp -> JsExp
JsOr :: JsExp -> JsExp -> JsExp

-- | Literal value type.
data JsLit
JsChar :: Char -> JsLit
JsStr :: String -> JsLit
JsInt :: Int -> JsLit
JsFloating :: Double -> JsLit
JsBool :: Bool -> JsLit

-- | A name of some kind.
data JsName
JsNameVar :: QName -> JsName
JsThis :: JsName
JsParametrizedType :: JsName
JsThunk :: JsName
JsForce :: JsName
JsApply :: JsName
JsParam :: Integer -> JsName
JsTmp :: Integer -> JsName
JsConstructor :: QName -> JsName
JsBuiltIn :: Name -> JsName
JsModuleName :: ModuleName -> JsName

-- | Error type.
data CompileError
Couldn'tFindImport :: ModuleName -> [FilePath] -> CompileError
EmptyDoBlock :: CompileError
FfiFormatBadChars :: SrcSpanInfo -> String -> CompileError
FfiFormatIncompleteArg :: SrcSpanInfo -> CompileError
FfiFormatInvalidJavaScript :: SrcSpanInfo -> String -> String -> CompileError
FfiFormatNoSuchArg :: SrcSpanInfo -> Int -> CompileError
FfiNeedsTypeSig :: Exp -> CompileError
GHCError :: String -> CompileError
InvalidDoBlock :: CompileError
ParseError :: SrcLoc -> String -> CompileError
ShouldBeDesugared :: String -> CompileError
UnableResolveQualified :: QName -> CompileError
UnsupportedDeclaration :: Decl -> CompileError
UnsupportedEnum :: Exp -> CompileError
UnsupportedExportSpec :: ExportSpec -> CompileError
UnsupportedExpression :: Exp -> CompileError
UnsupportedFieldPattern :: PatField -> CompileError
UnsupportedImport :: ImportDecl -> CompileError
UnsupportedLet :: CompileError
UnsupportedLetBinding :: Decl -> CompileError
UnsupportedLiteral :: Literal -> CompileError
UnsupportedModuleSyntax :: String -> Module -> CompileError
UnsupportedPattern :: Pat -> CompileError
UnsupportedQualStmt :: QualStmt -> CompileError
UnsupportedRecursiveDo :: CompileError
UnsupportedRhs :: Rhs -> CompileError
UnsupportedWhereInAlt :: Alt -> CompileError
UnsupportedWhereInMatch :: Match -> CompileError

-- | Compile monad.
newtype Compile a
Compile :: RWST CompileReader CompileWriter CompileState (ExceptT CompileError (ModuleT (ModuleInfo Compile) IO)) a -> Compile a

-- | Uns the compiler
[unCompile] :: Compile a -> RWST CompileReader CompileWriter CompileState (ExceptT CompileError (ModuleT (ModuleInfo Compile) IO)) a
type CompileModule a = ModuleT Symbols IO (Either CompileError (a, CompileState, CompileWriter))

-- | Print some value.
class Printable a
printJS :: Printable a => a -> Printer

-- | The JavaScript FFI interfacing monad.
data Fay a

-- | Configuration and globals for the compiler.
data CompileReader
CompileReader :: Config -> Sign -> Literal -> Compile JsExp -> Bool -> [Decl] -> Compile [JsStmt] -> CompileReader

-- | The compilation configuration.
[readerConfig] :: CompileReader -> Config
[readerCompileLit] :: CompileReader -> Sign -> Literal -> Compile JsExp
[readerCompileDecls] :: CompileReader -> Bool -> [Decl] -> Compile [JsStmt]
data CompileResult
CompileResult :: String -> [(String, FilePath)] -> Maybe [Mapping] -> CompileResult
[resOutput] :: CompileResult -> String
[resImported] :: CompileResult -> [(String, FilePath)]
[resSourceMappings] :: CompileResult -> Maybe [Mapping]

-- | Things written out by the compiler.
data CompileWriter
CompileWriter :: [JsStmt] -> [(String, JsExp)] -> [(String, JsExp)] -> CompileWriter

-- | Constructors.
[writerCons] :: CompileWriter -> [JsStmt]

-- | Fay to JS dispatchers.
[writerFayToJs] :: CompileWriter -> [(String, JsExp)]

-- | JS to Fay dispatchers.
[writerJsToFay] :: CompileWriter -> [(String, JsExp)]

-- | Configuration of the compiler. The fields with a leading underscore
data Config

-- | State of the compiler.
data CompileState
CompileState :: Map ModuleName Symbols -> [(QName, [QName])] -> [(QName, [Name])] -> [(QName, Maybe QName, Type)] -> [(ModuleName, FilePath)] -> Integer -> ModuleName -> Set ModulePath -> Bool -> Map QName Type -> CompileState

-- | Exported identifiers for all modules
[stateInterfaces] :: CompileState -> Map ModuleName Symbols

-- | Map types to constructors
[stateRecordTypes] :: CompileState -> [(QName, [QName])]

-- | Map constructors to fields
[stateRecords] :: CompileState -> [(QName, [Name])]

-- | Newtype constructor, destructor, wrapped type tuple
[stateNewtypes] :: CompileState -> [(QName, Maybe QName, Type)]

-- | Map of all imported modules and their source locations.
[stateImported] :: CompileState -> [(ModuleName, FilePath)]

-- | Depth of the current lexical scope, used for creating unshadowing
--   variables.
[stateNameDepth] :: CompileState -> Integer

-- | Name of the module currently being compiled.
[stateModuleName] :: CompileState -> ModuleName

-- | Module paths that have code generated for them.
[stateJsModulePaths] :: CompileState -> Set ModulePath

-- | Use JS Strings instead of [Char] for string literals?
[stateUseFromString] :: CompileState -> Bool

-- | Module level declarations having explicit type signatures
[stateTypeSigs] :: CompileState -> Map QName Type

-- | These are the data types that are serializable directly to native JS
--   data types. Strings, floating points and arrays. The others are:
--   actions in the JS monad, which are thunks that shouldn't be forced
--   when serialized but wrapped up as JS zero-arg functions, and unknown
--   types can't be converted but should at least be forced.
data FundamentalType
FunctionType :: [FundamentalType] -> FundamentalType
JsType :: FundamentalType -> FundamentalType
ListType :: FundamentalType -> FundamentalType
TupleType :: [FundamentalType] -> FundamentalType
UserDefined :: Name -> [FundamentalType] -> FundamentalType
Defined :: FundamentalType -> FundamentalType
Nullable :: FundamentalType -> FundamentalType
DateType :: FundamentalType
StringType :: FundamentalType
DoubleType :: FundamentalType
IntType :: FundamentalType
BoolType :: FundamentalType
PtrType :: FundamentalType
Automatic :: FundamentalType
UnknownType :: FundamentalType

-- | The state of the pretty printer.
data PrintState
PrintState :: Int -> Int -> Int -> Bool -> PrintState

-- | The current line.
[psLine] :: PrintState -> Int

-- | Current column.
[psColumn] :: PrintState -> Int

-- | Current indentation level.
[psIndentLevel] :: PrintState -> Int

-- | Just outputted a newline?
[psNewline] :: PrintState -> Bool

-- | Default state.
defaultPrintState :: PrintState

-- | Global options of the printer
data PrintReader
PrintReader :: Bool -> Bool -> Bool -> PrintReader

-- | Are we to pretty print?
[prPretty] :: PrintReader -> Bool

-- | Use pretty thunk names?
[prPrettyThunks] :: PrintReader -> Bool

-- | Use pretty operators?
[prPrettyOperators] :: PrintReader -> Bool

-- | default printer options (non-pretty printing)
defaultPrintReader :: PrintReader

-- | Output of printer
data PrintWriter
PrintWriter :: [Mapping] -> ShowS -> PrintWriter

-- | Source mappings.
[pwMappings] :: PrintWriter -> [Mapping]

-- | The current output.
[pwOutput] :: PrintWriter -> ShowS
pwOutputString :: PrintWriter -> String

-- | The printer.
newtype Printer
Printer :: RWS PrintReader PrintWriter PrintState () -> Printer
[runPrinter] :: Printer -> RWS PrintReader PrintWriter PrintState ()
execPrinter :: Printer -> PrintReader -> PrintWriter

-- | Print the given printer indented.
indented :: Printer -> Printer

-- | exec one of Printers depending on PrintReader property.
askIf :: (PrintReader -> Bool) -> Printer -> Printer -> Printer

-- | Output a newline and makes next line indented when prPretty is True.
--   Does nothing when prPretty is False
newline :: Printer

-- | Write out a raw string, respecting the indentation Note: if you pass a
--   string with newline characters, it will print them out even if
--   prPretty is set to False. Also next line won't be indented. If you
--   want write a smart newline (that is the one which will be written out
--   only if prPretty is true, and after which the line will be indented)
--   use <a>newline</a>)
write :: String -> Printer

-- | Generate a mapping from the Haskell location to the current point in
--   the output.
mapping :: SrcSpan -> Printer

-- | The serialization context indicates whether we're currently
--   serializing some value or a particular field in a user-defined data
--   type.
data SerializeContext
SerializeAnywhere :: SerializeContext
SerializeUserArg :: Int -> SerializeContext

-- | The name of a module split into a list for code generation.
data ModulePath

-- | Construct the complete ModulePath from a ModuleName.
mkModulePath :: ModuleName a -> ModulePath

-- | Construct intermediate module paths from a ModuleName. mkModulePaths
--   <a>A.B</a> =&gt; [[<a>A</a>], [<a>A</a>,<a>B</a>]]
mkModulePaths :: ModuleName a -> [ModulePath]

-- | Converting a QName to a ModulePath is only relevant for constructors
--   since they can conflict with module names.
mkModulePathFromQName :: QName a -> ModulePath
instance GHC.Base.Monad Fay.Types.Fay
instance GHC.Base.Functor Fay.Types.Fay
instance GHC.Base.Applicative Fay.Types.Fay
instance Control.Monad.Writer.Class.MonadWriter Fay.Types.CompileWriter Fay.Types.Compile
instance Control.Monad.State.Class.MonadState Fay.Types.CompileState Fay.Types.Compile
instance Control.Monad.Reader.Class.MonadReader Fay.Types.CompileReader Fay.Types.Compile
instance Control.Monad.IO.Class.MonadIO Fay.Types.Compile
instance Control.Monad.Error.Class.MonadError Fay.Types.CompileError.CompileError Fay.Types.Compile
instance GHC.Base.Monad Fay.Types.Compile
instance GHC.Base.Functor Fay.Types.Compile
instance GHC.Base.Applicative Fay.Types.Compile
instance GHC.Show.Show Fay.Types.CompileWriter
instance GHC.Show.Show Fay.Types.CompileState
instance Fay.Compiler.ModuleT.MonadModule Fay.Types.Compile
instance GHC.Base.Semigroup Fay.Types.CompileWriter
instance GHC.Base.Monoid Fay.Types.CompileWriter


-- | The internal FFI module.
module Fay.FFI

-- | The JavaScript FFI interfacing monad.
data Fay a

-- | Values that may be null Nullable x decodes to x, Null decodes to null.
data Nullable a
Nullable :: a -> Nullable a
Null :: Nullable a

-- | Values that may be undefined Defined x encodes to x, Undefined decodes
--   to undefined. An undefined property in a record will be removed when
--   encoding.
data Defined a
Defined :: a -> Defined a
Undefined :: Defined a

-- | Do not serialize the specified type. This is useful for, e.g.
--   
--   <pre>
--   foo :: String -&gt; String
--   foo = ffi "%1"
--   </pre>
--   
--   This would normally serialize and unserialize the string, for no
--   reason, in this case. Instead:
--   
--   <pre>
--   foo :: Ptr String -&gt; Ptr String
--   </pre>
--   
--   Will just give an identity function.
type Ptr a = a

-- | The opposite of <a>Ptr</a>. Serialize the specified polymorphic type.
--   
--   <pre>
--   foo :: Automatic a -&gt; String
--   </pre>
type Automatic a = a

-- | Declare a foreign action.
ffi :: IsString s => s -> a


-- | Desugars a reasonable amount of syntax to reduce duplication in code
--   generation.
module Fay.Compiler.Desugar

-- | Top level, desugar a whole module possibly returning errors
desugar :: (Data l, Typeable l) => l -> Module l -> IO (Either CompileError (Module l))

-- | Desugar with the option to specify a prefix for generated names.
--   Useful if you want to provide valid haskell names that HSE can print.
desugar' :: (Data l, Typeable l) => String -> l -> Module l -> IO (Either CompileError (Module l))

-- | (a) =&gt; a for patterns
desugarExpParen :: (Data l, Typeable l) => Module l -> Module l
desugarPatParen :: (Data l, Typeable l) => Module l -> Module l


-- | The Haskell→Javascript compiler.
module Fay.Compiler

-- | Runs compilation for a single module.
runCompileModule :: CompileReader -> CompileState -> Compile a -> CompileModule a

-- | Compile a Haskell source string to a JavaScript source string.
compileViaStr :: FilePath -> Config -> (Module -> Compile [JsStmt]) -> String -> IO (Either CompileError (Printer, CompileState, CompileWriter))

-- | Compile a module
compileWith :: (Monoid a, Semigroup a) => FilePath -> (a -> Module -> Compile a) -> (FilePath -> String -> Compile a) -> (X -> Module -> IO (Either CompileError Module)) -> String -> Compile (a, CompileState, CompileWriter)

-- | Compile Haskell expression.
compileExp :: Exp -> Compile JsExp

-- | Compile a declaration.
compileDecl :: Bool -> Decl -> Compile [JsStmt]

-- | Compile the top-level Fay module.
compileToplevelModule :: FilePath -> Module -> Compile [JsStmt]

-- | Compile a source string.
compileModuleFromContents :: String -> Compile ([JsStmt], [JsStmt])

-- | Compile a parse HSE module.
compileModuleFromAST :: ([JsStmt], [JsStmt]) -> Module -> Compile ([JsStmt], [JsStmt])

-- | Parse some Fay code.
parseFay :: Parseable ast => FilePath -> String -> ParseResult ast


-- | Main library entry point.
module Fay

-- | Error type.
data CompileError
Couldn'tFindImport :: ModuleName -> [FilePath] -> CompileError
EmptyDoBlock :: CompileError
FfiFormatBadChars :: SrcSpanInfo -> String -> CompileError
FfiFormatIncompleteArg :: SrcSpanInfo -> CompileError
FfiFormatInvalidJavaScript :: SrcSpanInfo -> String -> String -> CompileError
FfiFormatNoSuchArg :: SrcSpanInfo -> Int -> CompileError
FfiNeedsTypeSig :: Exp -> CompileError
GHCError :: String -> CompileError
InvalidDoBlock :: CompileError
ParseError :: SrcLoc -> String -> CompileError
ShouldBeDesugared :: String -> CompileError
UnableResolveQualified :: QName -> CompileError
UnsupportedDeclaration :: Decl -> CompileError
UnsupportedEnum :: Exp -> CompileError
UnsupportedExportSpec :: ExportSpec -> CompileError
UnsupportedExpression :: Exp -> CompileError
UnsupportedFieldPattern :: PatField -> CompileError
UnsupportedImport :: ImportDecl -> CompileError
UnsupportedLet :: CompileError
UnsupportedLetBinding :: Decl -> CompileError
UnsupportedLiteral :: Literal -> CompileError
UnsupportedModuleSyntax :: String -> Module -> CompileError
UnsupportedPattern :: Pat -> CompileError
UnsupportedQualStmt :: QualStmt -> CompileError
UnsupportedRecursiveDo :: CompileError
UnsupportedRhs :: Rhs -> CompileError
UnsupportedWhereInAlt :: Alt -> CompileError
UnsupportedWhereInMatch :: Match -> CompileError

-- | State of the compiler.
data CompileState
CompileState :: Map ModuleName Symbols -> [(QName, [QName])] -> [(QName, [Name])] -> [(QName, Maybe QName, Type)] -> [(ModuleName, FilePath)] -> Integer -> ModuleName -> Set ModulePath -> Bool -> Map QName Type -> CompileState

-- | Exported identifiers for all modules
[stateInterfaces] :: CompileState -> Map ModuleName Symbols

-- | Map types to constructors
[stateRecordTypes] :: CompileState -> [(QName, [QName])]

-- | Map constructors to fields
[stateRecords] :: CompileState -> [(QName, [Name])]

-- | Newtype constructor, destructor, wrapped type tuple
[stateNewtypes] :: CompileState -> [(QName, Maybe QName, Type)]

-- | Map of all imported modules and their source locations.
[stateImported] :: CompileState -> [(ModuleName, FilePath)]

-- | Depth of the current lexical scope, used for creating unshadowing
--   variables.
[stateNameDepth] :: CompileState -> Integer

-- | Name of the module currently being compiled.
[stateModuleName] :: CompileState -> ModuleName

-- | Module paths that have code generated for them.
[stateJsModulePaths] :: CompileState -> Set ModulePath

-- | Use JS Strings instead of [Char] for string literals?
[stateUseFromString] :: CompileState -> Bool

-- | Module level declarations having explicit type signatures
[stateTypeSigs] :: CompileState -> Map QName Type
data CompileResult
CompileResult :: String -> [(String, FilePath)] -> Maybe [Mapping] -> CompileResult
[resOutput] :: CompileResult -> String
[resImported] :: CompileResult -> [(String, FilePath)]
[resSourceMappings] :: CompileResult -> Maybe [Mapping]

-- | Compile the given file.
compileFile :: Config -> FilePath -> IO (Either CompileError String)

-- | Compile a file returning the resulting internal state of the compiler.
--   Don't use this directly, it's only exposed for the test suite.
compileFileWithState :: Config -> FilePath -> IO (Either CompileError (String, Maybe [Mapping], CompileState))

-- | Compile a file returning additional generated metadata.
compileFileWithResult :: Config -> FilePath -> IO (Either CompileError CompileResult)

-- | Compile the given file and write the output to the given path, or if
--   nothing given, stdout.
compileFromTo :: Config -> FilePath -> Maybe FilePath -> IO ()

-- | Compile the given file and write to the output, also generates HTML
--   and sourcemap files if configured.
compileFromToAndGenerateHtml :: Config -> FilePath -> FilePath -> IO (Either CompileError String)

-- | Convert a Haskell filename to a JS filename.
toJsName :: String -> String

-- | Convert a Haskell filename to a TypeScript filename.
toTsName :: String -> String

-- | Print a compile error for human consumption.
showCompileError :: CompileError -> String

-- | Get the JS runtime source. This will return the user supplied runtime
--   if it exists.
readConfigRuntime :: Config -> IO String
