200 lines
7.9 KiB
Idris
200 lines
7.9 KiB
Idris
module Quox.Whnf.Main
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import Quox.Whnf.Interface
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import Quox.Whnf.ComputeElimType
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import Quox.Whnf.TypeCase
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import Quox.Whnf.Coercion
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import Quox.Displace
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import Data.SnocVect
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%default total
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export covering CanWhnf Term Interface.isRedexT
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export covering CanWhnf Elim Interface.isRedexE
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covering
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CanWhnf Elim Interface.isRedexE where
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whnf defs ctx (F x u loc) with (lookupElim x defs) proof eq
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_ | Just y = whnf defs ctx $ setLoc loc $ displace u y
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_ | Nothing = pure $ Element (F x u loc) $ rewrite eq in Ah
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whnf _ _ (B i loc) = pure $ nred $ B i loc
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-- ((λ x ⇒ t) ∷ (π.x : A) → B) s ⇝ t[s∷A/x] ∷ B[s∷A/x]
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whnf defs ctx (App f s appLoc) = do
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Element f fnf <- whnf defs ctx f
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case nchoose $ isLamHead f of
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Left _ => case f of
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Ann (Lam {body, _}) (Pi {arg, res, _}) floc =>
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let s = Ann s arg s.loc in
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whnf defs ctx $ Ann (sub1 body s) (sub1 res s) appLoc
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Coe ty p q val _ => piCoe defs ctx ty p q val s appLoc
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Right nlh => pure $ Element (App f s appLoc) $ fnf `orNo` nlh
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-- case (s, t) ∷ (x : A) × B return p ⇒ C of { (a, b) ⇒ u } ⇝
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-- u[s∷A/a, t∷B[s∷A/x]] ∷ C[(s, t)∷((x : A) × B)/p]
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whnf defs ctx (CasePair pi pair ret body caseLoc) = do
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Element pair pairnf <- whnf defs ctx pair
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case nchoose $ isPairHead pair of
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Left _ => case pair of
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Ann (Pair {fst, snd, _}) (Sig {fst = tfst, snd = tsnd, _}) pairLoc =>
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let fst = Ann fst tfst fst.loc
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snd = Ann snd (sub1 tsnd fst) snd.loc
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in
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whnf defs ctx $ Ann (subN body [< fst, snd]) (sub1 ret pair) caseLoc
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Coe ty p q val _ => do
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sigCoe defs ctx pi ty p q val ret body caseLoc
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Right np =>
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pure $ Element (CasePair pi pair ret body caseLoc) $ pairnf `orNo` np
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-- case 'a ∷ {a,…} return p ⇒ C of { 'a ⇒ u } ⇝
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-- u ∷ C['a∷{a,…}/p]
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whnf defs ctx (CaseEnum pi tag ret arms caseLoc) = do
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Element tag tagnf <- whnf defs ctx tag
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case nchoose $ isTagHead tag of
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Left _ => case tag of
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Ann (Tag t _) (Enum ts _) _ =>
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let ty = sub1 ret tag in
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case lookup t arms of
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Just arm => whnf defs ctx $ Ann arm ty arm.loc
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Nothing => throw $ MissingEnumArm caseLoc t (keys arms)
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Coe ty p q val _ =>
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-- there is nowhere an equality can be hiding inside an enum type
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whnf defs ctx $
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CaseEnum pi (Ann val (dsub1 ty q) val.loc) ret arms caseLoc
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Right nt =>
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pure $ Element (CaseEnum pi tag ret arms caseLoc) $ tagnf `orNo` nt
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-- case zero ∷ ℕ return p ⇒ C of { zero ⇒ u; … } ⇝
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-- u ∷ C[zero∷ℕ/p]
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--
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-- case succ n ∷ ℕ return p ⇒ C of { succ n', π.ih ⇒ u; … } ⇝
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-- u[n∷ℕ/n', (case n ∷ ℕ ⋯)/ih] ∷ C[succ n ∷ ℕ/p]
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whnf defs ctx (CaseNat pi piIH nat ret zer suc caseLoc) = do
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Element nat natnf <- whnf defs ctx nat
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case nchoose $ isNatHead nat of
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Left _ =>
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let ty = sub1 ret nat in
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case nat of
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Ann (Zero _) (Nat _) _ =>
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whnf defs ctx $ Ann zer ty zer.loc
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Ann (Succ n succLoc) (Nat natLoc) _ =>
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let nn = Ann n (Nat natLoc) succLoc
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tm = subN suc [< nn, CaseNat pi piIH nn ret zer suc caseLoc]
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in
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whnf defs ctx $ Ann tm ty caseLoc
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Coe ty p q val _ =>
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-- same deal as Enum
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whnf defs ctx $
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CaseNat pi piIH (Ann val (dsub1 ty q) val.loc) ret zer suc caseLoc
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Right nn => pure $
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Element (CaseNat pi piIH nat ret zer suc caseLoc) $ natnf `orNo` nn
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-- case [t] ∷ [π.A] return p ⇒ C of { [x] ⇒ u } ⇝
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-- u[t∷A/x] ∷ C[[t] ∷ [π.A]/p]
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whnf defs ctx (CaseBox pi box ret body caseLoc) = do
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Element box boxnf <- whnf defs ctx box
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case nchoose $ isBoxHead box of
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Left _ => case box of
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Ann (Box val boxLoc) (BOX q bty tyLoc) _ =>
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let ty = sub1 ret box in
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whnf defs ctx $ Ann (sub1 body (Ann val bty val.loc)) ty caseLoc
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Coe ty p q val _ =>
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boxCoe defs ctx pi ty p q val ret body caseLoc
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Right nb =>
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pure $ Element (CaseBox pi box ret body caseLoc) $ boxnf `orNo` nb
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-- e : Eq (𝑗 ⇒ A) t u ⊢ e @0 ⇝ t ∷ A‹0/𝑗›
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-- e : Eq (𝑗 ⇒ A) t u ⊢ e @1 ⇝ u ∷ A‹1/𝑗›
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--
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-- ((δ 𝑖 ⇒ s) ∷ Eq (𝑗 ⇒ A) t u) @𝑘 ⇝ s‹𝑘/𝑖› ∷ A‹𝑘/𝑗›
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whnf defs ctx (DApp f p appLoc) = do
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Element f fnf <- whnf defs ctx f
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case nchoose $ isDLamHead f of
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Left _ => case f of
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Ann (DLam {body, _}) (Eq {ty, l, r, _}) _ =>
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whnf defs ctx $
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Ann (endsOr (setLoc appLoc l) (setLoc appLoc r) (dsub1 body p) p)
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(dsub1 ty p) appLoc
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Coe ty p' q' val _ =>
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eqCoe defs ctx ty p' q' val p appLoc
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Right ndlh => case p of
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K e _ => do
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Eq {l, r, ty, _} <- whnf0 defs ctx =<< computeElimType defs ctx f
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| ty => throw $ ExpectedEq ty.loc ctx.names ty
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whnf defs ctx $
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ends (Ann (setLoc appLoc l) ty.zero appLoc)
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(Ann (setLoc appLoc r) ty.one appLoc) e
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B {} => pure $ Element (DApp f p appLoc) $ fnf `orNo` ndlh `orNo` Ah
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-- e ∷ A ⇝ e
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whnf defs ctx (Ann s a annLoc) = do
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Element s snf <- whnf defs ctx s
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case nchoose $ isE s of
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Left _ => let E e = s in pure $ Element e $ noOr2 snf
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Right ne => do
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Element a anf <- whnf defs ctx a
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pure $ Element (Ann s a annLoc) $ ne `orNo` snf `orNo` anf
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whnf defs ctx (Coe (S _ (N ty)) _ _ val coeLoc) =
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whnf defs ctx $ Ann val ty coeLoc
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whnf defs ctx (Coe (S [< i] (Y ty)) p q val coeLoc) = do
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Element ty tynf <- whnf defs (extendDim i ctx) ty
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Element val valnf <- whnf defs ctx val
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pushCoe defs ctx i ty p q val coeLoc
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whnf defs ctx (Comp ty p q val r zero one compLoc) =
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-- comp [A] @p @p s { ⋯ } ⇝ s ∷ A
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if p == q then whnf defs ctx $ Ann val ty compLoc else
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case nchoose (isK r) of
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-- comp [A] @p @q s @0 { 0 j ⇒ t; ⋯ } ⇝ t‹q/j› ∷ A
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-- comp [A] @p @q s @1 { 1 j ⇒ t; ⋯ } ⇝ t‹q/j› ∷ A
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Left y => case r of
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K Zero _ => whnf defs ctx $ Ann (dsub1 zero q) ty compLoc
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K One _ => whnf defs ctx $ Ann (dsub1 one q) ty compLoc
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Right nk => do
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Element ty tynf <- whnf defs ctx ty
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pure $ Element (Comp ty p q val r zero one compLoc) $ tynf `orNo` nk
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whnf defs ctx (TypeCase ty ret arms def tcLoc) = do
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Element ty tynf <- whnf defs ctx ty
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Element ret retnf <- whnf defs ctx ret
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case nchoose $ isAnnTyCon ty of
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Left y =>
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let Ann ty (TYPE u _) _ = ty in
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reduceTypeCase defs ctx ty u ret arms def tcLoc
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Right nt => pure $
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Element (TypeCase ty ret arms def tcLoc) (tynf `orNo` retnf `orNo` nt)
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whnf defs ctx (CloE (Sub el th)) = whnf defs ctx $ pushSubstsWith' id th el
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whnf defs ctx (DCloE (Sub el th)) = whnf defs ctx $ pushSubstsWith' th id el
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covering
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CanWhnf Term Interface.isRedexT where
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whnf _ _ t@(TYPE {}) = pure $ nred t
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whnf _ _ t@(Pi {}) = pure $ nred t
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whnf _ _ t@(Lam {}) = pure $ nred t
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whnf _ _ t@(Sig {}) = pure $ nred t
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whnf _ _ t@(Pair {}) = pure $ nred t
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whnf _ _ t@(Enum {}) = pure $ nred t
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whnf _ _ t@(Tag {}) = pure $ nred t
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whnf _ _ t@(Eq {}) = pure $ nred t
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whnf _ _ t@(DLam {}) = pure $ nred t
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whnf _ _ t@(Nat {}) = pure $ nred t
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whnf _ _ t@(Zero {}) = pure $ nred t
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whnf _ _ t@(Succ {}) = pure $ nred t
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whnf _ _ t@(BOX {}) = pure $ nred t
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whnf _ _ t@(Box {}) = pure $ nred t
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-- s ∷ A ⇝ s (in term context)
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whnf defs ctx (E e) = do
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Element e enf <- whnf defs ctx e
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case nchoose $ isAnn e of
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Left _ => let Ann {tm, _} = e in pure $ Element tm $ noOr1 $ noOr2 enf
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Right na => pure $ Element (E e) $ na `orNo` enf
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whnf defs ctx (CloT (Sub tm th)) = whnf defs ctx $ pushSubstsWith' id th tm
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whnf defs ctx (DCloT (Sub tm th)) = whnf defs ctx $ pushSubstsWith' th id tm
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