sanctuary-type-classes
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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;Setoid Semigroup Foldable Functor (equals) (concat) (reduce) (map) | \ / | | | | \ | \ / | | | | \ | \ / | | | | \ | \ / | | | | \ | \ / | | | | \ Monoid Traversable | | | | \ (empty) (traverse) / | | \ \ / | | \ \ / / \ \ \ Profunctor / \ Bifunctor \ (promap) / \ (bimap) \ / \ \ / \ \ Alt Apply Extend (alt) (ap) (extend) / / \ \ / / \ \ / / \ \ / / \ \ / / \ \ Plus Applicative Chain Comonad (zero) (of) (chain) (extract) \ / \ / \ \ / \ / \ \ / \ / \ \ / \ / \ \ / \ / \ Alternative Monad ChainRec (chainRec)
TypeClass :: (String, Array TypeClass, a -> Boolean) -> TypeClassThe 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', [], hasMethod('foo'));
// Bar :: TypeClass
const Bar = Z.TypeClass('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 :: TypeClassTypeClass value for Setoid.
> Setoid.test(null)
true
Semigroup :: TypeClassTypeClass value for Semigroup.
> Semigroup.test('')
true
> Semigroup.test(0)
false
Monoid :: TypeClassTypeClass value for Monoid.
> Monoid.test('')
true
> Monoid.test(0)
false
Functor :: TypeClassTypeClass value for Functor.
> Functor.test([])
true
> Functor.test('')
false
Bifunctor :: TypeClassTypeClass value for Bifunctor.
> Bifunctor.test(Tuple('foo', 64))
true
> Bifunctor.test([])
false
Profunctor :: TypeClassTypeClass value for Profunctor.
> Profunctor.test(Math.sqrt)
true
> Profunctor.test([])
false
Apply :: TypeClassTypeClass value for Apply.
> Apply.test([])
true
> Apply.test({})
false
Applicative :: TypeClassTypeClass value for Applicative.
> Applicative.test([])
true
> Applicative.test({})
false
Chain :: TypeClassTypeClass value for Chain.
> Chain.test([])
true
> Chain.test({})
false
ChainRec :: TypeClassTypeClass value for ChainRec.
> ChainRec.test([])
true
> ChainRec.test({})
false
Monad :: TypeClassTypeClass value for Monad.
> Monad.test([])
true
> Monad.test({})
false
Alt :: TypeClassTypeClass value for Alt.
> Alt.test({})
true
> Alt.test('')
false
Plus :: TypeClassTypeClass value for Plus.
> Plus.test({})
true
> Plus.test('')
false
Alternative :: TypeClassTypeClass value for Alternative.
> Alternative.test([])
true
> Alternative.test({})
false
Foldable :: TypeClassTypeClass value for Foldable.
> Foldable.test({})
true
> Foldable.test('')
false
Traversable :: TypeClassTypeClass value for Traversable.
> Traversable.test([])
true
> Traversable.test({})
false
Extend :: TypeClassTypeClass value for Extend.
> Extend.test([])
true
> Extend.test({})
false
Comonad :: TypeClassTypeClass value for Comonad.
> Comonad.test(Identity(0))
true
> Comonad.test([])
false
toString :: a -> StringReturns a useful string representation of its argument.
Dispatches to the argument's toString method if appropriate.
Where practical, equals(eval(toString(x)), x) = true.
toString implementations are provided for the following built-in types:
Null, Undefined, Boolean, Number, Date, String, Array, Arguments, Error,
and Object.
> toString(-0)
'-0'
> toString(['foo', 'bar', 'baz'])
'["foo", "bar", "baz"]'
> toString({x: 1, y: 2, z: 3})
'{"x": 1, "y": 2, "z": 3}'
> toString(Cons(1, Cons(2, Cons(3, Nil))))
'Cons(1, Cons(2, Cons(3, Nil)))'
equals :: (a, b) -> BooleanReturns true if its arguments are of the same type and equal according
to the type's fantasy-land/equals method; false otherwise.
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.
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.
> equals(0, -0)
false
> equals(NaN, NaN)
true
> equals(Cons('foo', Cons('bar', Nil)), Cons('foo', Cons('bar', Nil)))
true
> equals(Cons('foo', Cons('bar', Nil)), Cons('bar', Cons('foo', Nil)))
false
concat :: Semigroup a => (a, a) -> aFunction wrapper for fantasy-land/concat.
fantasy-land/concat implementations are provided for the following
built-in types: String, Array, and Object.
> concat('abc', 'def')
'abcdef'
> concat([1, 2, 3], [4, 5, 6])
[1, 2, 3, 4, 5, 6]
> concat({x: 1, y: 2}, {y: 3, z: 4})
{x: 1, y: 3, z: 4}
> 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 -> mFunction wrapper for fantasy-land/empty.
fantasy-land/empty implementations are provided for the following
built-in types: String, Array, and Object.
> empty(String)
''
> empty(Array)
[]
> empty(Object)
{}
> empty(List)
Nil
map :: Functor f => (a -> b, f a) -> f bFunction wrapper for fantasy-land/map.
fantasy-land/map implementations are provided for the following
built-in types: Array, Object, and Function.
> map(Math.sqrt, [1, 4, 9])
[1, 2, 3]
> map(Math.sqrt, {x: 1, y: 4, z: 9})
{x: 1, y: 2, z: 3}
> map(Math.sqrt, s => s.length)('Sanctuary')
3
> map(Math.sqrt, Tuple('foo', 64))
Tuple('foo', 8)
> map(Math.sqrt, Nil)
Nil
> map(Math.sqrt, Cons(1, Cons(4, Cons(9, Nil))))
Cons(1, Cons(2, Cons(3, Nil)))
bimap :: Bifunctor f => (a -> b, c -> d, f a c) -> f b dFunction wrapper for fantasy-land/bimap.
> bimap(s => s.toUpperCase(), Math.sqrt, Tuple('foo', 64))
Tuple('FOO', 8)
promap :: Profunctor p => (a -> b, c -> d, p b c) -> p a dFunction wrapper for fantasy-land/promap.
fantasy-land/promap implementations are provided for the following
built-in types: Function.
> promap(Math.abs, x => x + 1, Math.sqrt)(-100)
11
ap :: Apply f => (f (a -> b), f a) -> f bFunction wrapper for fantasy-land/ap.
fantasy-land/ap implementations are provided for the following
built-in types: Array and Function.
> ap([Math.sqrt, x => x * x], [1, 4, 9, 16, 25])
[1, 2, 3, 4, 5, 1, 16, 81, 256, 625]
> ap(s => n => s.slice(0, n), s => Math.ceil(s.length / 2))('Haskell')
'Hask'
> ap(Identity(Math.sqrt), Identity(64))
Identity(8)
> 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 cLifts 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.
> lift2(x => y => Math.pow(x, y), [10], [1, 2, 3])
[10, 100, 1000]
> 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 dLifts 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.
> lift3(x => y => z => x + z + y, ['<'], ['>'], ['foo', 'bar', 'baz'])
['<foo>', '<bar>', '<baz>']
> lift3(x => y => z => x + z + y, Identity('<'), Identity('>'), Identity('baz'))
Identity('<baz>')
apFirst :: Apply f => (f a, f b) -> f aCombines two effectful actions, keeping only the result of the first.
Equivalent to Haskell's (<*) function.
This function is derived from lift2.
See also apSecond.
> apFirst([1, 2], [3, 4])
[1, 1, 2, 2]
> apFirst(Identity(1), Identity(2))
Identity(1)
apSecond :: Apply f => (f a, f b) -> f bCombines two effectful actions, keeping only the result of the second.
Equivalent to Haskell's (*>) function.
This function is derived from lift2.
See also apFirst.
> apSecond([1, 2], [3, 4])
[3, 4, 3, 4]
> apSecond(Identity(1), Identity(2))
Identity(2)
of :: Applicative f => (TypeRep f, a) -> f aFunction wrapper for fantasy-land/of.
fantasy-land/of implementations are provided for the following
built-in types: Array and Function.
> of(Array, 42)
[42]
> of(Function, 42)(null)
42
> of(List, 42)
Cons(42, Nil)
chain :: Chain m => (a -> m b, m a) -> m bFunction wrapper for fantasy-land/chain.
fantasy-land/chain implementations are provided for the following
built-in types: Array and Function.
> chain(x => [x, x], [1, 2, 3])
[1, 1, 2, 2, 3, 3]
> chain(x => x % 2 == 1 ? of(List, x) : Nil, Cons(1, Cons(2, Cons(3, Nil))))
Cons(1, Cons(3, Nil))
> chain(n => s => s.slice(0, n), s => Math.ceil(s.length / 2))('Haskell')
'Hask'
join :: Chain m => m (m a) -> m aRemoves one level of nesting from a nested monadic structure.
This function is derived from chain.
> join([[1], [2], [3]])
[1, 2, 3]
> join([[[1, 2, 3]]])
[[1, 2, 3]]
> join(Identity(Identity(1)))
Identity(1)
chainRec :: ChainRec m => (TypeRep m, (a -> c, b -> c, a) -> m c, a) -> m bFunction wrapper for fantasy-land/chainRec.
fantasy-land/chainRec implementations are provided for the following
built-in types: Array.
> 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?']
filter :: (Applicative f, Foldable f, Monoid (f a)) => (a -> Boolean, f a) -> f aFilters its second argument in accordance with the given predicate.
This function is derived from empty, of, and
reduce.
See also filterM.
> filter(x => x % 2 == 1, [1, 2, 3])
[1, 3]
> filter(x => x % 2 == 1, Cons(1, Cons(2, Cons(3, Nil))))
Cons(1, Cons(3, Nil))
filterM :: (Monad m, Monoid (m a)) => (a -> Boolean, m a) -> m aFilters its second argument in accordance with the given predicate.
This function is derived from empty, of, and
chain.
See also filter.
> filterM(x => x % 2 == 1, [1, 2, 3])
[1, 3]
> filterM(x => x % 2 == 1, Cons(1, Cons(2, Cons(3, Nil))))
Cons(1, Cons(3, Nil))
alt :: Alt f => (f a, f a) -> f aFunction wrapper for fantasy-land/alt.
fantasy-land/alt implementations are provided for the following
built-in types: Array and Object.
> alt([1, 2, 3], [4, 5, 6])
[1, 2, 3, 4, 5, 6]
> alt(Nothing, Nothing)
Nothing
> alt(Nothing, Just(1))
Just(1)
> alt(Just(2), Just(3))
Just(2)
zero :: Plus f => TypeRep f -> f aFunction wrapper for fantasy-land/zero.
fantasy-land/zero implementations are provided for the following
built-in types: Array and Object.
> zero(Array)
[]
> zero(Object)
{}
> zero(Maybe)
Nothing
reduce :: Foldable f => ((b, a) -> b, b, f a) -> bFunction wrapper for fantasy-land/reduce.
fantasy-land/reduce implementations are provided for the following
built-in types: Array and Object.
> reduce((xs, x) => [x].concat(xs), [], [1, 2, 3])
[3, 2, 1]
> reduce(concat, '', Cons('foo', Cons('bar', Cons('baz', Nil))))
'foobarbaz'
traverse :: (Applicative f, Traversable t) => (a -> f a, b -> f c, t b) -> f (t c)Function wrapper for fantasy-land/traverse.
fantasy-land/traverse implementations are provided for the following
built-in types: Array.
See also sequence.
> traverse(x => [x], x => x, [[1, 2, 3], [4, 5]])
[[1, 4], [1, 5], [2, 4], [2, 5], [3, 4], [3, 5]]
> traverse(Identity, x => Identity(x + 1), [1, 2, 3])
Identity([2, 3, 4])
sequence :: (Applicative f, Traversable t) => (a -> f a, t (f b)) -> f (t b)Inverts the given t (f b) to produce an f (t b).
This function is derived from traverse.
> sequence(x => [x], Identity([1, 2, 3]))
[Identity(1), Identity(2), Identity(3)]
> sequence(Identity, [Identity(1), Identity(2), Identity(3)])
Identity([1, 2, 3])
extend :: Extend w => (w a -> b, w a) -> w bFunction wrapper for fantasy-land/extend.
fantasy-land/extend implementations are provided for the following
built-in types: Array.
> extend(xs => xs.length, ['foo', 'bar', 'baz', 'quux'])
[4]
extract :: Comonad w => w a -> aFunction wrapper for fantasy-land/extract.
> extract(Identity(42))
42
FAQs
Standard library for Fantasy Land
The npm package sanctuary-type-classes receives a total of 39,845 weekly downloads. As such, sanctuary-type-classes popularity was classified as popular.
We found that sanctuary-type-classes demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 2 open source maintainers collaborating on the project.
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