Partible: Difference between revisions
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<haskell> | <haskell> | ||
module Partible where | |||
class Partible a where | class Partible a where | ||
part :: a -> (a, a) | |||
parts :: a -> [a] | |||
-- Minimal complete definition: part or parts -- | |||
part u = case parts u of u1:u2:_ -> (u1, u2) | |||
parts u = case part u of (u1, u2) -> u1 : parts u2 | |||
</haskell> | </haskell> | ||
Revision as of 22:21, 16 April 2021
Hint: if you're just looking for an introduction to partible types, see Plainly partible.
The Partible class
Partible types have an common (and austere) programming interface, this being captured by the Partible class:
module Partible where
class Partible a where
part :: a -> (a, a)
parts :: a -> [a]
-- Minimal complete definition: part or parts --
part u = case parts u of u1:u2:_ -> (u1, u2)
parts u = case part u of (u1, u2) -> u1 : parts u2In addition to implementing the methods of the class, partible types should satisfy certain equations; for an explanation of them along with why they should be satisfied, see Partible laws.