README.md
The Fantasy Land Specification "specifies interoperability of common
algebraic structures" by defining a number of type classes. For each type
class, it states laws which every member of a type must obey in order for
the type to be a member of the type class. In order for the Maybe type to
be considered a Functor, for example, every Maybe a value must have
a fantasy-land/map method which obeys the identity and composition laws.
This project provides:
TypeClass, a function for defining type classes;TypeClass value for each Fantasy Land type class;TypeClass :: (String, String, Array TypeClass, a -> Boolean) -> TypeClass</a>The arguments are:
true
if the value satisfies the requirements of the type class; false
otherwise.Example:
// hasMethod :: String -> a -> Boolean
const hasMethod = name => x => x != null && typeof x[name] == 'function';
// Foo :: TypeClass
const Foo = Z.TypeClass (
'my-package/Foo',
'http://example.com/my-package#Foo',
[],
hasMethod ('foo')
);
// Bar :: TypeClass
const Bar = Z.TypeClass (
'my-package/Bar',
'http://example.com/my-package#Bar',
[Foo],
hasMethod ('bar')
);
Types whose values have a foo method are members of the Foo type class.
Members of the Foo type class whose values have a bar method are also
members of the Bar type class.
Each TypeClass value has a test field: a function which accepts
any JavaScript value and returns true if the value satisfies the
type class's predicate and the predicates of all the type class's
dependencies; false otherwise.
TypeClass values may be used with sanctuary-def
to define parametrically polymorphic functions which verify their
type-class constraints at run time.
Setoid :: TypeClass</a>TypeClass value for Setoid.
> Z.Setoid.test (null)
true
> Z.Setoid.test (Useless)
false
> Z.Setoid.test ([1, 2, 3])
true
> Z.Setoid.test ([Useless])
false
Ord :: TypeClass</a>TypeClass value for Ord.
> Z.Ord.test (0)
true
> Z.Ord.test (Math.sqrt)
false
> Z.Ord.test ([1, 2, 3])
true
> Z.Ord.test ([Math.sqrt])
false
Semigroupoid :: TypeClass</a>TypeClass value for Semigroupoid.
> Z.Semigroupoid.test (Math.sqrt)
true
> Z.Semigroupoid.test (0)
false
Category :: TypeClass</a>TypeClass value for Category.
> Z.Category.test (Math.sqrt)
true
> Z.Category.test (0)
false
Semigroup :: TypeClass</a>TypeClass value for Semigroup.
> Z.Semigroup.test ('')
true
> Z.Semigroup.test (0)
false
Monoid :: TypeClass</a>TypeClass value for Monoid.
> Z.Monoid.test ('')
true
> Z.Monoid.test (0)
false
Group :: TypeClass</a>TypeClass value for Group.
> Z.Group.test (Sum (0))
true
> Z.Group.test ('')
false
Filterable :: TypeClass</a>TypeClass value for Filterable.
> Z.Filterable.test ({})
true
> Z.Filterable.test ('')
false
Functor :: TypeClass</a>TypeClass value for Functor.
> Z.Functor.test ([])
true
> Z.Functor.test ('')
false
Bifunctor :: TypeClass</a>TypeClass value for Bifunctor.
> Z.Bifunctor.test (Pair ('foo') (64))
true
> Z.Bifunctor.test ([])
false
Profunctor :: TypeClass</a>TypeClass value for Profunctor.
> Z.Profunctor.test (Math.sqrt)
true
> Z.Profunctor.test ([])
false
Apply :: TypeClass</a>TypeClass value for Apply.
> Z.Apply.test ([])
true
> Z.Apply.test ('')
false
Applicative :: TypeClass</a>TypeClass value for Applicative.
> Z.Applicative.test ([])
true
> Z.Applicative.test ({})
false
Chain :: TypeClass</a>TypeClass value for Chain.
> Z.Chain.test ([])
true
> Z.Chain.test ({})
false
ChainRec :: TypeClass</a>TypeClass value for ChainRec.
> Z.ChainRec.test ([])
true
> Z.ChainRec.test ({})
false
Monad :: TypeClass</a>TypeClass value for Monad.
> Z.Monad.test ([])
true
> Z.Monad.test ({})
false
Alt :: TypeClass</a>TypeClass value for Alt.
> Z.Alt.test ({})
true
> Z.Alt.test ('')
false
Plus :: TypeClass</a>TypeClass value for Plus.
> Z.Plus.test ({})
true
> Z.Plus.test ('')
false
Alternative :: TypeClass</a>TypeClass value for Alternative.
> Z.Alternative.test ([])
true
> Z.Alternative.test ({})
false
Foldable :: TypeClass</a>TypeClass value for Foldable.
> Z.Foldable.test ({})
true
> Z.Foldable.test ('')
false
Traversable :: TypeClass</a>TypeClass value for Traversable.
> Z.Traversable.test ([])
true
> Z.Traversable.test ('')
false
Extend :: TypeClass</a>TypeClass value for Extend.
> Z.Extend.test ([])
true
> Z.Extend.test ({})
false
Comonad :: TypeClass</a>TypeClass value for Comonad.
> Z.Comonad.test (Identity (0))
true
> Z.Comonad.test ([])
false
Contravariant :: TypeClass</a>TypeClass value for Contravariant.
> Z.Contravariant.test (Math.sqrt)
true
> Z.Contravariant.test ([])
false
equals :: (a, b) -> Boolean</a>Returns true if its arguments are equal; false otherwise.
Specifically:
Arguments with different type identities are unequal.
If the first argument has a fantasy-land/equals method,
that method is invoked to determine whether the arguments are
equal (fantasy-land/equals implementations are provided for the
following built-in types: Null, Undefined, Boolean, Number, Date,
RegExp, String, Array, Arguments, Error, Object, and Function).
Otherwise, the arguments are equal if their entries are equal (according to this algorithm).
The algorithm supports circular data structures. Two arrays are equal
if they have the same index paths and for each path have equal values.
Two arrays which represent [1, [1, [1, [1, [1, ...]]]]], for example,
are equal even if their internal structures differ. Two objects are equal
if they have the same property paths and for each path have equal values.
> Z.equals (0, -0)
true
> Z.equals (NaN, NaN)
true
> Z.equals (Cons (1, Cons (2, Nil)), Cons (1, Cons (2, Nil)))
true
> Z.equals (Cons (1, Cons (2, Nil)), Cons (2, Cons (1, Nil)))
false
lt :: (a, b) -> Boolean</a>Returns true if its arguments are of the same type and the first is
less than the second according to the type's fantasy-land/lte
method; false otherwise.
This function is derived from lte.
> Z.lt (0, 0)
false
> Z.lt (0, 1)
true
> Z.lt (1, 0)
false
lte :: (a, b) -> Boolean</a>Returns true if its arguments are of the same type and the first
is less than or equal to the second according to the type's
fantasy-land/lte method; false otherwise.
fantasy-land/lte implementations are provided for the following
built-in types: Null, Undefined, Boolean, Number, Date, String, Array,
Arguments, and Object.
The algorithm supports circular data structures in the same manner as
equals.
> Z.lte (0, 0)
true
> Z.lte (0, 1)
true
> Z.lte (1, 0)
false
gt :: (a, b) -> Boolean</a>Returns true if its arguments are of the same type and the first is
greater than the second according to the type's fantasy-land/lte
method; false otherwise.
This function is derived from lte.
> Z.gt (0, 0)
false
> Z.gt (0, 1)
false
> Z.gt (1, 0)
true
gte :: (a, b) -> Boolean</a>Returns true if its arguments are of the same type and the first
is greater than or equal to the second according to the type's
fantasy-land/lte method; false otherwise.
This function is derived from lte.
> Z.gte (0, 0)
true
> Z.gte (0, 1)
false
> Z.gte (1, 0)
true
min :: Ord a => (a, a) -> a</a>Returns the smaller of its two arguments.
This function is derived from lte.
See also max.
> Z.min (10, 2)
2
> Z.min (new Date ('1999-12-31'), new Date ('2000-01-01'))
new Date ('1999-12-31')
> Z.min ('10', '2')
'10'
max :: Ord a => (a, a) -> a</a>Returns the larger of its two arguments.
This function is derived from lte.
See also min.
> Z.max (10, 2)
10
> Z.max (new Date ('1999-12-31'), new Date ('2000-01-01'))
new Date ('2000-01-01')
> Z.max ('10', '2')
'2'
clamp :: Ord a => (a, a, a) -> a</a>Takes a lower bound, an upper bound, and a value of the same type. Returns the value if it is within the bounds; the nearer bound otherwise.
This function is derived from min and max.
> Z.clamp (0, 100, 42)
42
> Z.clamp (0, 100, -1)
0
> Z.clamp ('A', 'Z', '~')
'Z'
compose :: Semigroupoid c => (c j k, c i j) -> c i k</a>Function wrapper for fantasy-land/compose.
fantasy-land/compose implementations are provided for the following
built-in types: Function.
> Z.compose (Math.sqrt, x => x + 1) (99)
10
id :: Category c => TypeRep c -> c</a>Function wrapper for fantasy-land/id.
fantasy-land/id implementations are provided for the following
built-in types: Function.
> Z.id (Function) ('foo')
'foo'
concat :: Semigroup a => (a, a) -> a</a>Function wrapper for fantasy-land/concat.
fantasy-land/concat implementations are provided for the following
built-in types: String, Array, and Object.
> Z.concat ('abc', 'def')
'abcdef'
> Z.concat ([1, 2, 3], [4, 5, 6])
[1, 2, 3, 4, 5, 6]
> Z.concat ({x: 1, y: 2}, {y: 3, z: 4})
{x: 1, y: 3, z: 4}
> Z.concat (Cons ('foo', Cons ('bar', Cons ('baz', Nil))), Cons ('quux', Nil))
Cons ('foo', Cons ('bar', Cons ('baz', Cons ('quux', Nil))))
empty :: Monoid m => TypeRep m -> m</a>Function wrapper for fantasy-land/empty.
fantasy-land/empty implementations are provided for the following
built-in types: String, Array, and Object.
> Z.empty (String)
''
> Z.empty (Array)
[]
> Z.empty (Object)
{}
> Z.empty (List)
Nil
invert :: Group g => g -> g</a>Function wrapper for fantasy-land/invert.
> Z.invert (Sum (5))
Sum (-5)
filter :: Filterable f => (a -> Boolean, f a) -> f a</a>Function wrapper for fantasy-land/filter. Discards every element
which does not satisfy the predicate.
fantasy-land/filter implementations are provided for the following
built-in types: Array and Object.
See also reject.
> Z.filter (x => x % 2 == 1, [1, 2, 3])
[1, 3]
> Z.filter (x => x % 2 == 1, {x: 1, y: 2, z: 3})
{x: 1, z: 3}
> Z.filter (x => x % 2 == 1, Cons (1, Cons (2, Cons (3, Nil))))
Cons (1, Cons (3, Nil))
> Z.filter (x => x % 2 == 1, Nothing)
Nothing
> Z.filter (x => x % 2 == 1, Just (0))
Nothing
> Z.filter (x => x % 2 == 1, Just (1))
Just (1)
reject :: Filterable f => (a -> Boolean, f a) -> f a</a>Discards every element which satisfies the predicate.
This function is derived from filter.
> Z.reject (x => x % 2 == 1, [1, 2, 3])
[2]
> Z.reject (x => x % 2 == 1, {x: 1, y: 2, z: 3})
{y: 2}
> Z.reject (x => x % 2 == 1, Cons (1, Cons (2, Cons (3, Nil))))
Cons (2, Nil)
> Z.reject (x => x % 2 == 1, Nothing)
Nothing
> Z.reject (x => x % 2 == 1, Just (0))
Just (0)
> Z.reject (x => x % 2 == 1, Just (1))
Nothing
map :: Functor f => (a -> b, f a) -> f b</a>Function wrapper for fantasy-land/map.
fantasy-land/map implementations are provided for the following
built-in types: Array, Object, and Function.
> Z.map (Math.sqrt, [1, 4, 9])
[1, 2, 3]
> Z.map (Math.sqrt, {x: 1, y: 4, z: 9})
{x: 1, y: 2, z: 3}
> Z.map (Math.sqrt, s => s.length) ('Sanctuary')
3
> Z.map (Math.sqrt, Pair ('foo') (64))
Pair ('foo') (8)
> Z.map (Math.sqrt, Nil)
Nil
> Z.map (Math.sqrt, Cons (1, Cons (4, Cons (9, Nil))))
Cons (1, Cons (2, Cons (3, Nil)))
flip :: Functor f => (f (a -> b), a) -> f b</a>Maps over the given functions, applying each to the given value.
This function is derived from map.
> Z.flip (x => y => x + y, '!') ('foo')
'foo!'
> Z.flip ([Math.floor, Math.ceil], 1.5)
[1, 2]
> Z.flip ({floor: Math.floor, ceil: Math.ceil}, 1.5)
{floor: 1, ceil: 2}
> Z.flip (Cons (Math.floor, Cons (Math.ceil, Nil)), 1.5)
Cons (1, Cons (2, Nil))
bimap :: Bifunctor f => (a -> b, c -> d, f a c) -> f b d</a>Function wrapper for fantasy-land/bimap.
> Z.bimap (s => s.toUpperCase (), Math.sqrt, Pair ('foo') (64))
Pair ('FOO') (8)
mapLeft :: Bifunctor f => (a -> b, f a c) -> f b c</a>Maps the given function over the left side of a Bifunctor.
> Z.mapLeft (Math.sqrt, Pair (64) (9))
Pair (8) (9)
promap :: Profunctor p => (a -> b, c -> d, p b c) -> p a d</a>Function wrapper for fantasy-land/promap.
fantasy-land/promap implementations are provided for the following
built-in types: Function.
> Z.promap (Math.abs, x => x + 1, Math.sqrt) (-100)
11
ap :: Apply f => (f (a -> b), f a) -> f b</a>Function wrapper for fantasy-land/ap.
fantasy-land/ap implementations are provided for the following
built-in types: Array, Object, and Function.
> Z.ap ([Math.sqrt, x => x * x], [1, 4, 9, 16, 25])
[1, 2, 3, 4, 5, 1, 16, 81, 256, 625]
> Z.ap ({a: Math.sqrt, b: x => x * x}, {a: 16, b: 10, c: 1})
{a: 4, b: 100}
> Z.ap (s => n => s.slice (0, n), s => Math.ceil (s.length / 2)) ('Haskell')
'Hask'
> Z.ap (Identity (Math.sqrt), Identity (64))
Identity (8)
> Z.ap (Cons (Math.sqrt, Cons (x => x * x, Nil)), Cons (16, Cons (100, Nil)))
Cons (4, Cons (10, Cons (256, Cons (10000, Nil))))
lift2 :: Apply f => (a -> b -> c, f a, f b) -> f c</a>Lifts a -> b -> c to Apply f => f a -> f b -> f c and returns the
result of applying this to the given arguments.
This function is derived from map and ap.
See also lift3.
> Z.lift2 (x => y => Math.pow (x, y), [10], [1, 2, 3])
[10, 100, 1000]
> Z.lift2 (x => y => Math.pow (x, y), Identity (10), Identity (3))
Identity (1000)
lift3 :: Apply f => (a -> b -> c -> d, f a, f b, f c) -> f d</a>Lifts a -> b -> c -> d to Apply f => f a -> f b -> f c -> f d and
returns the result of applying this to the given arguments.
This function is derived from map and ap.
See also lift2.
> Z.lift3 (x => y => z => x + z + y,
. ['<', '['],
. ['>', ']'],
. ['foo', 'bar', 'baz'])
[ '<foo>', '<bar>', '<baz>',
. '<foo]', '<bar]', '<baz]',
. '[foo>', '[bar>', '[baz>',
. '[foo]', '[bar]', '[baz]' ]
> Z.lift3 (x => y => z => x + z + y,
. Identity ('<'),
. Identity ('>'),
. Identity ('baz'))
Identity ('<baz>')
apFirst :: Apply f => (f a, f b) -> f a</a>Combines two effectful actions, keeping only the result of the first.
Equivalent to Haskell's (<*) function.
This function is derived from lift2.
See also apSecond.
> Z.apFirst ([1, 2], [3, 4])
[1, 1, 2, 2]
> Z.apFirst (Identity (1), Identity (2))
Identity (1)
apSecond :: Apply f => (f a, f b) -> f b</a>Combines two effectful actions, keeping only the result of the second.
Equivalent to Haskell's (*>) function.
This function is derived from lift2.
See also apFirst.
> Z.apSecond ([1, 2], [3, 4])
[3, 4, 3, 4]
> Z.apSecond (Identity (1), Identity (2))
Identity (2)
of :: Applicative f => (TypeRep f, a) -> f a</a>Function wrapper for fantasy-land/of.
fantasy-land/of implementations are provided for the following
built-in types: Array and Function.
> Z.of (Array, 42)
[42]
> Z.of (Function, 42) (null)
42
> Z.of (List, 42)
Cons (42, Nil)
append :: (Applicative f, Semigroup (f a)) => (a, f a) -> f a</a>Returns the result of appending the first argument to the second.
This function is derived from concat and of.
See also prepend.
> Z.append (3, [1, 2])
[1, 2, 3]
> Z.append (3, Cons (1, Cons (2, Nil)))
Cons (1, Cons (2, Cons (3, Nil)))
prepend :: (Applicative f, Semigroup (f a)) => (a, f a) -> f a</a>Returns the result of prepending the first argument to the second.
This function is derived from concat and of.
See also append.
> Z.prepend (1, [2, 3])
[1, 2, 3]
> Z.prepend (1, Cons (2, Cons (3, Nil)))
Cons (1, Cons (2, Cons (3, Nil)))
chain :: Chain m => (a -> m b, m a) -> m b</a>Function wrapper for fantasy-land/chain.
fantasy-land/chain implementations are provided for the following
built-in types: Array and Function.
> Z.chain (x => [x, x], [1, 2, 3])
[1, 1, 2, 2, 3, 3]
> Z.chain (x => x % 2 == 1 ? Z.of (List, x) : Nil,
. Cons (1, Cons (2, Cons (3, Nil))))
Cons (1, Cons (3, Nil))
> Z.chain (n => s => s.slice (0, n),
. s => Math.ceil (s.length / 2))
. ('Haskell')
'Hask'
join :: Chain m => m (m a) -> m a</a>Removes one level of nesting from a nested monadic structure.
This function is derived from chain.
> Z.join ([[1], [2], [3]])
[1, 2, 3]
> Z.join ([[[1, 2, 3]]])
[[1, 2, 3]]
> Z.join (Identity (Identity (1)))
Identity (1)
chainRec :: ChainRec m => (TypeRep m, (a -> c, b -> c, a) -> m c, a) -> m b</a>Function wrapper for fantasy-land/chainRec.
fantasy-land/chainRec implementations are provided for the following
built-in types: Array.
> Z.chainRec (
. Array,
. (next, done, s) => s.length == 2 ? [s + '!', s + '?'].map (done)
. : [s + 'o', s + 'n'].map (next),
. ''
. )
['oo!', 'oo?', 'on!', 'on?', 'no!', 'no?', 'nn!', 'nn?']
alt :: Alt f => (f a, f a) -> f a</a>Function wrapper for fantasy-land/alt.
fantasy-land/alt implementations are provided for the following
built-in types: Array and Object.
> Z.alt ([1, 2, 3], [4, 5, 6])
[1, 2, 3, 4, 5, 6]
> Z.alt (Nothing, Nothing)
Nothing
> Z.alt (Nothing, Just (1))
Just (1)
> Z.alt (Just (2), Just (3))
Just (2)
zero :: Plus f => TypeRep f -> f a</a>Function wrapper for fantasy-land/zero.
fantasy-land/zero implementations are provided for the following
built-in types: Array and Object.
> Z.zero (Array)
[]
> Z.zero (Object)
{}
> Z.zero (Maybe)
Nothing
reduce :: Foldable f => ((b, a) -> b, b, f a) -> b</a>Function wrapper for fantasy-land/reduce.
fantasy-land/reduce implementations are provided for the following
built-in types: Array and Object.
> Z.reduce ((xs, x) => [x].concat (xs), [], [1, 2, 3])
[3, 2, 1]
> Z.reduce (Z.concat, '', Cons ('foo', Cons ('bar', Cons ('baz', Nil))))
'foobarbaz'
> Z.reduce (Z.concat, '', {foo: 'x', bar: 'y', baz: 'z'})
'yzx'
size :: Foldable f => f a -> Integer</a>Returns the number of elements of the given structure.
This function is derived from reduce.
> Z.size ([])
0
> Z.size (['foo', 'bar', 'baz'])
3
> Z.size (Nil)
0
> Z.size (Cons ('foo', Cons ('bar', Cons ('baz', Nil))))
3
all :: Foldable f => (a -> Boolean, f a) -> Boolean</a>Returns true if all the elements of the structure satisfy the
predicate; false otherwise.
This function is derived from reduce.
> Z.all (Number.isInteger, [])
true
> Z.all (Number.isInteger, [1, 2, 3])
true
> Z.all (Number.isInteger, [0, 0.25, 0.5, 0.75, 1])
false
any :: Foldable f => (a -> Boolean, f a) -> Boolean</a>Returns true if any element of the structure satisfies the predicate;
false otherwise.
This function is derived from reduce.
> Z.any (Number.isInteger, [])
false
> Z.any (Number.isInteger, [1, 2, 3])
true
> Z.any (Number.isInteger, [0, 0.25, 0.5, 0.75, 1])
true
none :: Foldable f => (a -> Boolean, f a) -> Boolean</a>Returns true if none of the elements of the structure satisfies the
predicate; false otherwise.
This function is derived from any. Z.none (pred, foldable) is
equivalent to !(Z.any (pred, foldable)).
See also all.
> Z.none (Number.isInteger, [])
true
> Z.none (Number.isInteger, [0, 0.25, 0.5, 0.75, 1])
false
elem :: (Setoid a, Foldable f) => (a, f a) -> Boolean</a>Takes a value and a structure and returns true if the
value is an element of the structure; false otherwise.
This function is derived from equals and
reduce.
> Z.elem ('c', ['a', 'b', 'c'])
true
> Z.elem ('x', ['a', 'b', 'c'])
false
> Z.elem (3, {x: 1, y: 2, z: 3})
true
> Z.elem (8, {x: 1, y: 2, z: 3})
false
> Z.elem (0, Just (0))
true
> Z.elem (0, Just (1))
false
> Z.elem (0, Nothing)
false
intercalate :: (Monoid m, Foldable f) => (m, f m) -> m</a>Concatenates the elements of the given structure, separating each pair of adjacent elements with the given separator.
This function is derived from concat, empty,
and reduce.
> Z.intercalate (', ', [])
''
> Z.intercalate (', ', ['foo', 'bar', 'baz'])
'foo, bar, baz'
> Z.intercalate (', ', Nil)
''
> Z.intercalate (', ', Cons ('foo', Cons ('bar', Cons ('baz', Nil))))
'foo, bar, baz'
> Z.intercalate ([0, 0, 0], [])
[]
> Z.intercalate ([0, 0, 0], [[1], [2, 3], [4, 5, 6], [7, 8], [9]])
[1, 0, 0, 0, 2, 3, 0, 0, 0, 4, 5, 6, 0, 0, 0, 7, 8, 0, 0, 0, 9]
foldMap :: (Monoid m, Foldable f) => (TypeRep m, a -> m, f a) -> m</a>Deconstructs a foldable by mapping every element to a monoid and concatenating the results.
This function is derived from concat, empty,
and reduce.
> Z.foldMap (String, f => f.name, [Math.sin, Math.cos, Math.tan])
'sincostan'
reverse :: (Applicative f, Foldable f, Monoid (f a)) => f a -> f a</a>Reverses the elements of the given structure.
This function is derived from concat, empty,
of, and reduce.
> Z.reverse ([1, 2, 3])
[3, 2, 1]
> Z.reverse (Cons (1, Cons (2, Cons (3, Nil))))
Cons (3, Cons (2, Cons (1, Nil)))
sort :: (Ord a, Applicative f, Foldable f, Monoid (f a)) => f a -> f a</a>Performs a stable sort of the elements of the given structure,
using lte for comparisons.
This function is derived from lte, concat,
empty, of, and reduce.
See also sortBy.
> Z.sort (['foo', 'bar', 'baz'])
['bar', 'baz', 'foo']
> Z.sort ([Just (2), Nothing, Just (1)])
[Nothing, Just (1), Just (2)]
> Z.sort (Cons ('foo', Cons ('bar', Cons ('baz', Nil))))
Cons ('bar', Cons ('baz', Cons ('foo', Nil)))
sortBy :: (Ord b, Applicative f, Foldable f, Monoid (f a)) => (a -> b, f a) -> f a</a>Performs a stable sort of the elements of the given structure,
using lte to compare the values produced by applying the
given function to each element of the structure.
This function is derived from lte, concat,
empty, of, and reduce.
See also sort.
> Z.sortBy (s => s.length, ['red', 'green', 'blue'])
['red', 'blue', 'green']
> Z.sortBy (s => s.length, ['black', 'white'])
['black', 'white']
> Z.sortBy (s => s.length, ['white', 'black'])
['white', 'black']
> Z.sortBy (s => s.length, Cons ('red', Cons ('green', Cons ('blue', Nil))))
Cons ('red', Cons ('blue', Cons ('green', Nil)))
traverse :: (Applicative f, Traversable t) => (TypeRep f, a -> f b, t a) -> f (t b)</a>Function wrapper for fantasy-land/traverse.
fantasy-land/traverse implementations are provided for the following
built-in types: Array and Object.
See also sequence.
> Z.traverse (Array, x => x, [[1, 2, 3], [4, 5]])
[[1, 4], [1, 5], [2, 4], [2, 5], [3, 4], [3, 5]]
> Z.traverse (Identity, x => Identity (x + 1), [1, 2, 3])
Identity ([2, 3, 4])
sequence :: (Applicative f, Traversable t) => (TypeRep f, t (f a)) -> f (t a)</a>Inverts the given t (f a) to produce an f (t a).
This function is derived from traverse.
> Z.sequence (Array, Identity ([1, 2, 3]))
[Identity (1), Identity (2), Identity (3)]
> Z.sequence (Identity, [Identity (1), Identity (2), Identity (3)])
Identity ([1, 2, 3])
extend :: Extend w => (w a -> b, w a) -> w b</a>Function wrapper for fantasy-land/extend.
fantasy-land/extend implementations are provided for the following
built-in types: Array and Function.
> Z.extend (ss => ss.join (''), ['x', 'y', 'z'])
['xyz', 'yz', 'z']
> Z.extend (f => f ([3, 4]), Z.reverse) ([1, 2])
[4, 3, 2, 1]
duplicate :: Extend w => w a -> w (w a)</a>Adds one level of nesting to a comonadic structure.
This function is derived from extend.
> Z.duplicate (Identity (1))
Identity (Identity (1))
> Z.duplicate ([1])
[[1]]
> Z.duplicate ([1, 2, 3])
[[1, 2, 3], [2, 3], [3]]
> Z.duplicate (Z.reverse) ([1, 2]) ([3, 4])
[4, 3, 2, 1]
extract :: Comonad w => w a -> a</a>Function wrapper for fantasy-land/extract.
> Z.extract (Identity (42))
42
contramap :: Contravariant f => (b -> a, f a) -> f b</a>Function wrapper for fantasy-land/contramap.
fantasy-land/contramap implementations are provided for the following
built-in types: Function.
> Z.contramap (s => s.length, Math.sqrt) ('Sanctuary')
3