Data.HSet.SubHSet

Documentation

class SubHSet els els2 where

Takes subset of some hset, including subset of same elements in different order

>>> let x = (HSCons "hello" $ HSCons 1234 $ HSCons 12.123 HSNil) :: HSet '[String, Int, Double]

>>> subHSet x :: HSet '[Double, Int]
HSCons (12.123) (HSCons (1234) (HSNil))

>>> subHSet x :: HSet '[String, Double]
HSCons ("hello") (HSCons (12.123) (HSNil))

>>> subHSet x :: HSet '[Int, String]
HSCons (1234) (HSCons ("hello") (HSNil))

Methods

subHSet :: HSet els -> HSet els2

Instances

SubHSet els ([] *)

(HGettable els el, NotElem * el els2, SubHSet els els2) => SubHSet els ((:) * el els2)

type SubHSettable = SubHSet

hnarrow :: SubHSettable els subels => proxy subels -> HSet els -> HSet subels

Like subHSet but with proxy for convenience

>>> let x = (HSCons "hello" $ HSCons 123 $ HSCons 345 HSNil) :: HSet '[String, Int, Integer]

>>> hnarrow (Proxy :: Proxy '[]) x
HSNil

>>> hnarrow (Proxy :: Proxy '[String]) x
HSCons ("hello") (HSNil)

>>> hnarrow (Proxy :: Proxy '[Int, Integer]) x
HSCons (123) (HSCons (345) (HSNil))

>>> hnarrow (Proxy :: Proxy '[Integer, Int]) x
HSCons (345) (HSCons (123) (HSNil))