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August 29, 2022 04:31
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Issues with interface reduction of types in a mutual definition (Verified Applicative)
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------------------------------- Base Imports --------------------------------- | |
import Syntax.PreorderReasoning -- for long proofs | |
import Data.List -- for list lemmas | |
------------------------------ Custom Imports -------------------------------- | |
import VerifiedFunctor | |
--------------------------------- Pragmas ------------------------------------ | |
%default total | |
%hide Prelude.(<$>) | |
%hide Prelude.Interfaces.(<*>) | |
%hide Prelude.Interfaces.pure | |
%ambiguity_depth 15 | |
------------------------------- Operators ------------------------------------ | |
infixl 3 <*> | |
----------------------------- Definitions ------------------------------------ | |
public export | |
interface VerifiedApplicative (f : Type -> Type) where | |
-- functions | |
pure : a -> f a | |
(<*>) : f (a -> b) -> f a -> f b | |
-- proofs | |
idLaw : (x : f a) -> pure Prelude.Basics.id <*> x = x | |
comLaw : {a, b : Type} | |
-> (x : f a) -> (g : f (a -> b)) -> (h : f (b -> c)) | |
-> (((pure (.)) <*> h) <*> g) <*> x = h <*> (g <*> x) | |
homLaw : pure f <*> pure x = pure (f x) | |
intLaw : {u : f (a -> b)} -> u <*> pure x = pure (\g => g x) <*> u | |
namespace ListLemmas | |
public export | |
applyDistributesOverAppendRight : (VerifiedFunctor List, VerifiedApplicative List) | |
=> (fs, gs : List (a -> b)) | |
-> (xs : List a) | |
-> (fs `Prelude.List.(++)` gs) <*> xs = | |
((<*>) {f = List} fs xs) ++ (gs <*> xs) | |
public export | |
applyDistributesOverMap : (VerifiedApplicative List, VerifiedFunctor List) | |
=> (((<$>) {f = List} (g .) gs) <*> xs) = (g <$> (gs <*> xs)) | |
public export | |
implementation [vappl] VerifiedApplicative List where | |
pure = (:: []) | |
[] <*> xs = [] | |
(f :: fs) <*> xs = (f <$> xs) ++ (fs <*> xs) | |
idLaw [] = Refl | |
idLaw (x :: xs) = Calc $ -- hole : x :: ((id <$> xs) ++ []) = x :: xs | |
|~ (x :: ((id <$> xs) ++ [])) -- The type of the LHS | |
~~ x :: xs ...(cong (\u => x :: u) (idLaw xs)) -- The type of RHS | |
comLaw gs hs [] = Refl | |
comLaw gs hs (x :: xs) = Calc $ | |
|~ (((x .) <$> hs) ++ ((((.) <$> xs) ++ []) <*> hs)) <*> gs | |
~~ (((x .) <$> hs) <*> gs) ++ (((((.) <$> xs) ++ []) <*> hs) <*> gs) | |
...( applyDistributesOverAppendRight ((x .) <$> hs) ((((.) <$> xs) ++ []) <*> hs) gs ) | |
~~ ( (((x .) <$> hs) <*> gs) ++ (xs <*> (hs <*> gs)) ) | |
...( cong (\u => (((x .) <$> hs) <*> gs) ++ u) (comLaw gs hs xs) ) | |
~~ (x <$> (hs <*> gs)) ++ (xs <*> (hs <*> gs)) | |
...( cong (\u => u ++ (xs <*> (hs <*> gs))) applyDistributesOverMap ) | |
homLaw = ?waiting5 | |
intLaw = ?waiting6 | |
namespace ListLemmas | |
-- applyDistributesOverAppendRight : VerifiedApplicative List | |
-- => (fs, gs : List (a -> b)) | |
-- -> (xs : List a) | |
-- -> (fs `Prelude.List.(++)` gs) <*> xs = | |
-- (fs <*> xs) ++ (gs <*> xs) | |
applyDistributesOverAppendRight [] gs xs = ?thisDoesNotReduce | |
applyDistributesOverAppendRight (f :: fs) gs xs = ?hole |
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