Documentation

Std.Internal.Do.Triple.SpecLemmas

Hoare triple specifications for select functions #

This module contains Hoare triple specifications for some functions in Core. The specifications follow the Triple x pre post epost argument order, program first.

Monad #

theorem Std.Internal.Do.Spec.pure {m : Type u → Type v} [Monad m] {Pred : Type w} {EPred : Type w'} [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α : Type u} {post : αPred} {epost : EPred} (a : α) :
post a Pure.pure a post; epost
theorem Std.Internal.Do.Spec.bind {m : Type u → Type v} [Monad m] {Pred : Type w} {EPred : Type w'} [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α β : Type u} {post : βPred} {epost : EPred} (x : m α) (f : αm β) :
wp x (fun (a : α) => wp (f a) post epost) epost x >>= f post; epost
theorem Std.Internal.Do.Spec.map {m : Type u → Type v} [Monad m] {Pred : Type w} {EPred : Type w'} [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α β : Type u} {post : βPred} {epost : EPred} (f : αβ) (x : m α) :
wp x (fun (a : α) => post (f a)) epost f <$> x post; epost
theorem Std.Internal.Do.Spec.seq {m : Type u → Type v} [Monad m] {Pred : Type w} {EPred : Type w'} [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α β : Type u} {post : βPred} {epost : EPred} (x : m (αβ)) (y : m α) :
wp x (fun (f : αβ) => wp y (fun (a : α) => post (f a)) epost) epost x <*> y post; epost

MonadLift #

theorem Std.Internal.Do.Spec.monadLift_StateT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α σ : Type u} {epost : EPred} (x : m α) (post : ασPred) :
fun (s : σ) => wp x (fun (a : α) => post a s) epost MonadLift.monadLift x post; epost
theorem Std.Internal.Do.Spec.monadLift_ReaderT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α ρ : Type u} {epost : EPred} (x : m α) (post : αρPred) :
fun (r : ρ) => wp x (fun (a : α) => post a r) epost MonadLift.monadLift x post; epost
theorem Std.Internal.Do.Spec.monadLift_ExceptT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α ε : Type u} (x : m α) (post : αPred) (epost : EPost.Cons✝ (εPred) EPred) :
wp x post epost.tail MonadLift.monadLift x post; epost
theorem Std.Internal.Do.Spec.monadLift_OptionT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α : Type u} (x : m α) (post : αPred) (epost : EPost.Cons✝ Pred EPred) :
wp x post epost.tail MonadLift.monadLift x post; epost
theorem Std.Internal.Do.Spec.monadLift_Id {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α : Type u} {post : αPred} {epost : EPred} (x : Id α) :
post x.run monadLift x post; epost

MonadLiftT #

theorem Std.Internal.Do.Spec.UnfoldLift.monadLift_trans {m : Type u → Type v} {n : Type u → Type u_1} {o : Type u → Type u_2} {α : Type u} [MonadLift n o] [MonadLiftT m n] (x : m α) :
theorem Std.Internal.Do.Spec.UnfoldLift.monadLift_refl {m : Type u → Type v} {α : Type u} (x : m α) :

MonadFunctor #

theorem Std.Internal.Do.Spec.monadMap_StateT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {σ : Type u} {epost : EPred} (f : {β : Type u} → m βm β) {α : Type u} (x : StateT σ m α) (post : ασPred) :
fun (s : σ) => wp (f (x.run s)) (fun (x : α × σ) => match x with | (a, s') => post a s') epost MonadFunctor.monadMap (fun {β : Type u} => f) x post; epost
theorem Std.Internal.Do.Spec.monadMap_ReaderT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ρ : Type u} {epost : EPred} (f : {β : Type u} → m βm β) {α : Type u} (x : ReaderT ρ m α) (post : αρPred) :
fun (r : ρ) => wp (f (x.run r)) (fun (a : α) => post a r) epost MonadFunctor.monadMap (fun {β : Type u} => f) x post; epost
theorem Std.Internal.Do.Spec.monadMap_ExceptT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε : Type u} (f : {β : Type u} → m βm β) {α : Type u} (x : ExceptT ε m α) (post : αPred) (epost : EPost.Cons✝ (εPred) EPred) :
wp (f x.run) (EPost.Cons.pushExcept post epost) epost.tail MonadFunctor.monadMap (fun {β : Type u} => f) x post; epost
theorem Std.Internal.Do.Spec.monadMap_OptionT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] (f : {β : Type u} → m βm β) {α : Type u} (x : OptionT m α) (post : αPred) (epost : EPost.Cons✝ Pred EPred) :
wp (f x.run) (EPost.Cons.pushOption post epost) epost.tail MonadFunctor.monadMap (fun {β : Type u} => f) x post; epost
theorem Std.Internal.Do.Spec.monadMap_refl {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α : Type u} {f : {β : Type u} → m βm β} {post : αPred} {epost : EPred} (x : m α) :
wp (f x) post epost monadMap f x post; epost

MonadControl #

theorem Std.Internal.Do.Spec.liftWith_StateT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {σ α : Type u} {epost : EPred} (f : ({β : Type u} → StateT σ m βm (β × σ))m α) (post : ασPred) :
fun (s : σ) => wp (f fun {β : Type u} (x : StateT σ m β) => x.run s) (fun (a : α) => post a s) epost MonadControl.liftWith f post; epost
theorem Std.Internal.Do.Spec.liftWith_ReaderT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ρ α : Type u} {epost : EPred} (f : ({β : Type u} → ReaderT ρ m βm β)m α) (post : αρPred) :
fun (r : ρ) => wp (f fun {β : Type u} (x : ReaderT ρ m β) => x.run r) (fun (a : α) => post a r) epost MonadControl.liftWith f post; epost
theorem Std.Internal.Do.Spec.liftWith_ExceptT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε α : Type u} (f : ({β : Type u} → ExceptT ε m βm (Except ε β))m α) (post : αPred) (epost : EPost.Cons✝ (εPred) EPred) :
wp (f fun {β : Type u} (x : ExceptT ε m β) => x.run) post epost.tail MonadControl.liftWith f post; epost
theorem Std.Internal.Do.Spec.liftWith_OptionT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α : Type u} (f : ({β : Type u} → OptionT m βm (Option β))m α) (post : αPred) (epost : EPost.Cons✝ Pred EPred) :
wp (f fun {β : Type u} (x : OptionT m β) => x.run) post epost.tail MonadControl.liftWith f post; epost
theorem Std.Internal.Do.Spec.restoreM_StateT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α σ : Type u} {epost : EPred} (x : m (α × σ)) (post : ασPred) :
fun (x_1 : σ) => wp x (fun (x : α × σ) => match x with | (a, s) => post a s) epost MonadControl.restoreM x post; epost
theorem Std.Internal.Do.Spec.restoreM_ReaderT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α ρ : Type u} {epost : EPred} (x : m α) (post : αρPred) :
fun (r : ρ) => wp x (fun (a : α) => post a r) epost MonadControl.restoreM x post; epost
theorem Std.Internal.Do.Spec.restoreM_ExceptT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε α : Type u} (x : m (Except ε α)) (post : αPred) (epost : EPost.Cons✝ (εPred) EPred) :
wp x (EPost.Cons.pushExcept post epost) epost.tail MonadControl.restoreM x post; epost
theorem Std.Internal.Do.Spec.restoreM_OptionT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α : Type u} (x : m (Option α)) (post : αPred) (epost : EPost.Cons✝ Pred EPred) :
wp x (EPost.Cons.pushOption post epost) epost.tail MonadControl.restoreM x post; epost

MonadControlT #

theorem Std.Internal.Do.Spec.liftWith_refl {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α : Type u} {post : αPred} {epost : EPred} (f : ({β : Type u} → m βm β)m α) :
wp (f fun {β : Type u} (x : m β) => x) post epost liftWith f post; epost
theorem Std.Internal.Do.Spec.restoreM_refl {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α : Type u} {post : αPred} {epost : EPred} (x : stM m m α) :
wp (Pure.pure x) post epost restoreM x post; epost

ReaderT #

theorem Std.Internal.Do.Spec.read_ReaderT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ρ : Type u} {epost : EPred} (post : ρρPred) :
fun (r : ρ) => post r r MonadReaderOf.read post; epost
theorem Std.Internal.Do.Spec.withReader_ReaderT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ρ α : Type u} {epost : EPred} (f : ρρ) (x : ReaderT ρ m α) (post : αρPred) :
fun (r : ρ) => wp x (fun (a : α) (x : ρ) => post a r) epost (f r) MonadWithReaderOf.withReader f x post; epost
theorem Std.Internal.Do.Spec.adapt_ReaderT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ρ ρ' α : Type u} {epost : EPred} (f : ρρ') (x : ReaderT ρ' m α) (post : αρPred) :
fun (r : ρ) => wp x (fun (a : α) (x : ρ') => post a r) epost (f r) ReaderT.adapt f x post; epost

StateT #

theorem Std.Internal.Do.Spec.get_StateT {m : Type u → Type v} [Monad m] {Pred : Type w} {EPred : Type w'} [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {epost : EPred} {σ : Type u} (post : σσPred) :
fun (s : σ) => post s s MonadStateOf.get post; epost
theorem Std.Internal.Do.Spec.set_StateT {m : Type u → Type v} [Monad m] {Pred : Type w} {EPred : Type w'} [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {epost : EPred} {σ : Type u} (s : σ) (post : PUnitσPred) :
fun (x : σ) => post PUnit.unit s set s post; epost
theorem Std.Internal.Do.Spec.modifyGet_StateT {m : Type u → Type v} [Monad m] {Pred : Type w} {EPred : Type w'} [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {epost : EPred} {σ α : Type u} (f : σα × σ) (post : ασPred) :
fun (s : σ) => post (f s).fst (f s).snd MonadStateOf.modifyGet f post; epost

Lifting MonadStateOf #

theorem Std.Internal.Do.Spec.UnfoldLift.set {m : Type u → Type v} {n : Type u → Type u_1} {σ : Type u} [MonadLift m n] [MonadStateOf σ m] (s : σ) :
theorem Std.Internal.Do.Spec.UnfoldLift.modifyGet {m : Type u → Type v} {n : Type u → Type u_1} {σ α : Type u} [MonadLift m n] [MonadStateOf σ m] (f : σα × σ) :

Lifting MonadReaderOf #

ExceptT #

theorem Std.Internal.Do.Spec.run_ExceptT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε α : Type u} (x : ExceptT ε m α) (post : αPred) (epost : EPost.Cons✝ (εPred) EPred) :
wp x post epost x.run EPost.Cons.pushExcept post epost; epost.tail
theorem Std.Internal.Do.Spec.throw_ExceptT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε α : Type u} (err : ε) (post : αPred) (epost : EPost.Cons✝ (εPred) EPred) :
epost.head err MonadExceptOf.throw err post; epost
theorem Std.Internal.Do.Spec.tryCatch_ExceptT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε α : Type u} (x : ExceptT ε m α) (h : εExceptT ε m α) (post : αPred) (epost : EPost.Cons✝ (εPred) EPred) :
wp x post (EPost.Cons.mk✝ (fun (e : ε) => wp (h e) post epost) epost.tail) MonadExceptOf.tryCatch x h post; epost
theorem Std.Internal.Do.Spec.orElse_ExceptT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε α : Type u} (x : ExceptT ε m α) (h : UnitExceptT ε m α) (post : αPred) (epost : EPost.Cons✝ (εPred) EPred) :
wp x post (EPost.Cons.mk✝ (fun (x : ε) => wp (h ()) post epost) epost.tail) OrElse.orElse x h post; epost
theorem Std.Internal.Do.Spec.adapt_ExceptT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε ε' α : Type u} (f : εε') (x : ExceptT ε m α) (post : αPred) (epost : EPost.Cons✝ (ε'Pred) EPred) :
wp x post (EPost.Cons.mk✝ (fun (e : ε) => epost.head (f e)) epost.tail) ExceptT.adapt f x post; epost

Except #

theorem Std.Internal.Do.Spec.throw_Except {ε : Type u_1} {α : Type u_2} {post : αProp} {epost : EPost⟨εProp} (err : ε) :
epost.head err MonadExceptOf.throw err post; epost
theorem Std.Internal.Do.Spec.tryCatch_Except {ε : Type u_1} {α : Type u_2} {post : αProp} {epost : EPost⟨εProp} (x : Except ε α) (h : εExcept ε α) :
wp x post epost⟨fun (e : ε) => wp (h e) post epost MonadExceptOf.tryCatch x h post; epost
theorem Std.Internal.Do.Spec.orElse_Except {ε : Type u_1} {α : Type u_2} {post : αProp} {epost : EPost⟨εProp} (x : Except ε α) (h : UnitExcept ε α) :
wp x post epost⟨fun (x : ε) => wp (h ()) post epost OrElse.orElse x h post; epost

OptionT #

theorem Std.Internal.Do.Spec.run_OptionT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α : Type u} (x : OptionT m α) (post : αPred) (epost : EPost.Cons✝ Pred EPred) :
wp x post epost x.run EPost.Cons.pushOption post epost; epost.tail
theorem Std.Internal.Do.Spec.throw_OptionT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α : Type u} (err : PUnit) (post : αPred) (epost : EPost.Cons✝ Pred EPred) :
epost.head MonadExceptOf.throw err post; epost
theorem Std.Internal.Do.Spec.tryCatch_OptionT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α : Type u} (x : OptionT m α) (h : PUnitOptionT m α) (post : αPred) (epost : EPost.Cons✝ Pred EPred) :
wp x post (EPost.Cons.mk✝ (wp (h PUnit.unit) post epost) epost.tail) MonadExceptOf.tryCatch x h post; epost
theorem Std.Internal.Do.Spec.orElse_OptionT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α : Type u} (x : OptionT m α) (h : UnitOptionT m α) (post : αPred) (epost : EPost.Cons✝ Pred EPred) :
wp x post (EPost.Cons.mk✝ (wp (h ()) post epost) epost.tail) OrElse.orElse x h post; epost

Option #

theorem Std.Internal.Do.Spec.throw_Option {α : Type u_1} {epost : Prop} {post : αProp} (err : PUnit) :
epost MonadExceptOf.throw err post; epost
theorem Std.Internal.Do.Spec.tryCatch_Option {α : Type u_1} {post : αProp} {epost : Prop} (x : Option α) (h : PUnitOption α) :
wp x post (wp (h PUnit.unit) post epost) MonadExceptOf.tryCatch x h post; epost
theorem Std.Internal.Do.Spec.orElse_Option {α : Type u_1} (x : Option α) (h : UnitOption α) (post : αProp) (epost : Prop) :
wp x post (wp (h ()) post epost) OrElse.orElse x h post; epost

EStateM #

theorem Std.Internal.Do.Spec.get_EStateM {σ ε : Type} (post : σσProp) (epost : εσProp) :
fun (s : σ) => post s s MonadStateOf.get post; epost
theorem Std.Internal.Do.Spec.set_EStateM {σ ε : Type} (s : σ) (post : PUnitσProp) (epost : εσProp) :
fun (x : σ) => post PUnit.unit s set s post; epost
theorem Std.Internal.Do.Spec.modifyGet_EStateM {σ α ε : Type} (f : σα × σ) (post : ασProp) (epost : εσProp) :
fun (s : σ) => post (f s).fst (f s).snd MonadStateOf.modifyGet f post; epost
theorem Std.Internal.Do.Spec.throw_EStateM {ε α σ : Type} (err : ε) (post : ασProp) (epost : εσProp) :
epost err MonadExceptOf.throw err post; epost
theorem Std.Internal.Do.Spec.tryCatch_EStateM {ε σ α : Type} (x : EStateM ε σ α) (h : εEStateM ε σ α) (post : ασProp) (epost : εσProp) :
fun (s : σ) => wp x post (fun (e : ε) (s' : σ) => wp (h e) post epost s') s MonadExceptOf.tryCatch x h post; epost
theorem Std.Internal.Do.Spec.orElse_EStateM {ε σ α : Type} (x : EStateM ε σ α) (h : UnitEStateM ε σ α) (post : ασProp) (epost : εσProp) :
fun (s : σ) => wp x post (fun (x : ε) (s' : σ) => wp (h ()) post epost s') s OrElse.orElse x h post; epost
theorem Std.Internal.Do.Spec.adaptExcept_EStateM {ε ε' σ α : Type} (f : εε') (x : EStateM ε σ α) (post : ασProp) (epost : ε'σProp) :
wp x post fun (e : ε) => epost (f e) EStateM.adaptExcept f x post; epost

Lifting MonadExceptOf #

theorem Std.Internal.Do.Spec.throw_MonadExcept {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε : Type u_1} {α : Type u} {post : αPred} {epost : EPred} [MonadExceptOf ε m] (err : ε) :
wp (MonadExceptOf.throw err) post epost throw err post; epost
theorem Std.Internal.Do.Spec.tryCatch_MonadExcept {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε : Type u_1} {α : Type u} {post : αPred} {epost : EPred} [MonadExceptOf ε m] (x : m α) (h : εm α) :
wp (MonadExceptOf.tryCatch x h) post epost tryCatch x h post; epost
theorem Std.Internal.Do.Spec.throw_ReaderT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε : Type u_1} {α ρ : Type u} {epost : EPred} [MonadExceptOf ε m] (err : ε) (post : αρPred) :
theorem Std.Internal.Do.Spec.throw_StateT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε : Type u_1} {α σ : Type u} {epost : EPred} [MonadExceptOf ε m] (err : ε) (post : ασPred) :
theorem Std.Internal.Do.Spec.throw_ExceptT_lift {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε α ε' : Type u} [MonadExceptOf ε m] (err : ε) (post : αPred) (epost : EPost.Cons✝ (ε'Pred) EPred) :
wp (MonadExceptOf.throw err) (fun (r : Except ε' α) => match r with | Except.ok a => post a | Except.error e => epost.head e) epost.tail MonadExceptOf.throw err post; epost
theorem Std.Internal.Do.Spec.throw_Option_lift {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε α : Type u} [MonadExceptOf ε m] (err : ε) (post : αPred) (epost : EPost.Cons✝ Pred EPred) :
theorem Std.Internal.Do.Spec.tryCatch_ReaderT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε : Type u_1} {ρ α : Type u} {epost : EPred} [MonadExceptOf ε m] (x : ReaderT ρ m α) (h : εReaderT ρ m α) (post : αρPred) :
fun (r : ρ) => wp (MonadExceptOf.tryCatch (x.run r) fun (e : ε) => (h e).run r) (fun (a : α) => post a r) epost MonadExceptOf.tryCatch x h post; epost
theorem Std.Internal.Do.Spec.tryCatch_StateT {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε : Type u_1} {σ α : Type u} {epost : EPred} [MonadExceptOf ε m] (x : StateT σ m α) (h : εStateT σ m α) (post : ασPred) :
fun (s : σ) => wp (MonadExceptOf.tryCatch (x.run s) fun (e : ε) => (h e).run s) (fun (x : α × σ) => match x with | (a, s') => post a s') epost MonadExceptOf.tryCatch x h post; epost
theorem Std.Internal.Do.Spec.tryCatch_ExceptT_lift {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε ε' α : Type u} [MonadExceptOf ε m] (x : ExceptT ε' m α) (h : εExceptT ε' m α) (post : αPred) (epost : EPost.Cons✝ (ε'Pred) EPred) :
wp (MonadExceptOf.tryCatch x h) (fun (x : Except ε' α) => match x with | Except.ok a => post a | Except.error e => epost.head e) epost.tail MonadExceptOf.tryCatch x h post; epost
theorem Std.Internal.Do.Spec.tryCatch_OptionT_lift {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ε α : Type u} [MonadExceptOf ε m] (x : OptionT m α) (h : εOptionT m α) (post : αPred) (epost : EPost.Cons✝ Pred EPred) :
theorem Std.Internal.Do.Spec.monadMap_trans {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α : Type u} {post : αPred} {epost : EPred} {n₁ n₂ : Type u → Type v} [MonadFunctor n₁ m] [MonadFunctorT n₂ n₁] {f : {β : Type u} → n₂ βn₂ β} (x : m α) :
wp (MonadFunctor.monadMap (fun {β : Type u} => monadMap fun {β : Type u} => f) x) post epost monadMap (fun {β : Type u} => f) x post; epost
theorem Std.Internal.Do.Spec.liftWith_trans {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α : Type u} {post : αPred} {epost : EPred} {n₁ n₂ : Type u → Type v} [MonadControl n₁ m] [MonadControlT n₂ n₁] (f : ({β : Type u} → m βn₂ (stM n₂ m β))n₂ α) :
wp (MonadControl.liftWith fun (x₂ : {β : Type u} → m βn₁ (MonadControl.stM n₁ m β)) => liftWith fun (x₁ : {β : Type u} → n₁ βn₂ (stM n₂ n₁ β)) => f fun {β : Type u} => x₁ x₂) post epost liftWith f post; epost
theorem Std.Internal.Do.Spec.restoreM_trans {m : Type u → Type v} {Pred EPred : Type u} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {α : Type u} {post : αPred} {epost : EPred} {n₁ n₂ : Type u → Type v} [MonadControl n₁ m] [MonadControlT n₂ n₁] (x : stM n₂ m α) :
wp (MonadControl.restoreM (restoreM x)) post epost restoreM x post; epost
def Std.Internal.Do.Invariant (α : Type u₁) (β : Type u₂) (Pred : Type uₚ) :
Type (max (max u₂ uₚ) u₁)

The type of loop invariants used by the specifications of for ... in ... loops. A loop invariant maps the elements consumed so far, the elements remaining, and the accumulator state to an assertion.

Equations
Instances For
    @[reducible, inline]
    noncomputable abbrev Std.Internal.Do.Invariant.withEarlyReturnNewDo {α : Type u₁} {β γ : Type u₂} (Pred : Type u_1) [Assertion Pred] (onContinue : List αList αβPred) (onReturn : γβPred) :
    Invariant α (Option γ × β) Pred

    An invariant combinator for loops with early return, for the new do elaborator which uses Prod for the state tuple: onContinue is the invariant while iterating, onReturn holds once the loop returned early with a value.

    Equations
    • One or more equations did not get rendered due to their size.
    Instances For
      theorem Std.Internal.Do.Spec.forIn'_list {α : Type u₁} {β : Type u₂} {m : Type u₂ → Type v} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {xs : List α} {init : β} {f : (a : α) → a xsβm (ForInStep β)} (inv : Invariant α β Pred) {epost : EPred} (step : ∀ (pref : List α) (cur : α) (suff : List α) (h : xs = pref ++ cur :: suff) (b : β), inv pref (cur :: suff) b f cur b fun (r : ForInStep β) => match r with | ForInStep.yield b' => inv (pref ++ [cur]) suff b' | ForInStep.done b' => inv xs [] b'; epost ) :
      inv [] xs init forIn' xs init f fun (b : β) => inv xs [] b; epost
      theorem Std.Internal.Do.Spec.forIn'_list_const_inv {α : Type u₁} {β : Type u₂} {m : Type u₂ → Type v} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {xs : List α} {init : β} {f : (a : α) → a xsβm (ForInStep β)} {inv : βPred} {epost : EPred} (step : ∀ (x : α) (hx : x xs) (b : β), inv b f x hx b fun (r : ForInStep β) => match r with | ForInStep.yield b' => inv b' | ForInStep.done b' => inv b'; epost ) :
      inv init forIn' xs init f inv; epost
      theorem Std.Internal.Do.Spec.forIn_list {α : Type u₁} {β : Type u₂} {m : Type u₂ → Type v} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {xs : List α} {init : β} {f : αβm (ForInStep β)} (inv : Invariant α β Pred) {epost : EPred} (step : ∀ (pref : List α) (cur : α) (suff : List α), xs = pref ++ cur :: suff∀ (b : β), inv pref (cur :: suff) b f cur b fun (r : ForInStep β) => match r with | ForInStep.yield b' => inv (pref ++ [cur]) suff b' | ForInStep.done b' => inv xs [] b'; epost ) :
      inv [] xs init forIn xs init f fun (b : β) => inv xs [] b; epost
      theorem Std.Internal.Do.Spec.forIn_list_const_inv {α : Type u₁} {β : Type u₂} {m : Type u₂ → Type v} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {xs : List α} {init : β} {f : αβm (ForInStep β)} {inv : βPred} {epost : EPred} (step : ∀ (hd : α) (b : β), inv b f hd b fun (r : ForInStep β) => match r with | ForInStep.yield b' => inv b' | ForInStep.done b' => inv b'; epost ) :
      inv init forIn xs init f inv; epost
      theorem Std.Internal.Do.Spec.foldlM_list {α : Type u₁} {β : Type u₂} {m : Type u₂ → Type v} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {xs : List α} {init : β} {f : βαm β} (inv : Invariant α β Pred) {epost : EPred} (step : ∀ (pref : List α) (cur : α) (suff : List α), xs = pref ++ cur :: suff∀ (b : β), inv pref (cur :: suff) b f b cur fun (b' : β) => inv (pref ++ [cur]) suff b'; epost ) :
      inv [] xs init List.foldlM f init xs fun (b : β) => inv xs [] b; epost
      theorem Std.Internal.Do.Spec.foldlM_list_const_inv {α : Type u₁} {β : Type u₂} {m : Type u₂ → Type v} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {xs : List α} {init : β} {f : βαm β} {inv : βPred} {epost : EPred} (step : ∀ (hd : α) (b : β), inv b f b hd fun (b' : β) => inv b'; epost ) :
      inv init List.foldlM f init xs inv; epost
      theorem Std.Internal.Do.Spec.forIn'_pure {α : Type u₁} {β : Type u₂} {m : Type u₂ → Type v} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ρ : Type w} {d : Membership α ρ} [ForIn' m ρ α d] [ForIn Id ρ α] [LawfulMemForInId ρ α] [PureForIn' m ρ α] {xs : ρ} {init : β} {f : (a : α) → a xsβm (ForInStep β)} (inv : Invariant α β Pred) {epost : EPred} (step : ∀ (pref : List α) (cur : α) (suff : List α) (h : ForIn.toList xs = pref ++ cur :: suff) (b : β), inv pref (cur :: suff) b f cur b fun (r : ForInStep β) => match r with | ForInStep.yield b' => inv (pref ++ [cur]) suff b' | ForInStep.done b' => inv (ForIn.toList xs) [] b'; epost ) :
      inv [] (ForIn.toList xs) init forIn' xs init f fun (b : β) => inv (ForIn.toList xs) [] b; epost

      Every container with a PureForIn' instance iterates over ForIn.toList, so one specification covers them all.

      theorem Std.Internal.Do.Spec.forIn_pure {α : Type u₁} {β : Type u₂} {m : Type u₂ → Type v} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {ρ : Type w} [ForIn m ρ α] [ForIn Id ρ α] [PureForIn m ρ α] {xs : ρ} {init : β} {f : αβm (ForInStep β)} (inv : Invariant α β Pred) {epost : EPred} (step : ∀ (pref : List α) (cur : α) (suff : List α), ForIn.toList xs = pref ++ cur :: suff∀ (b : β), inv pref (cur :: suff) b f cur b fun (r : ForInStep β) => match r with | ForInStep.yield b' => inv (pref ++ [cur]) suff b' | ForInStep.done b' => inv (ForIn.toList xs) [] b'; epost ) :
      inv [] (ForIn.toList xs) init forIn xs init f fun (b : β) => inv (ForIn.toList xs) [] b; epost

      Every container with a PureForIn instance iterates over ForIn.toList, so one specification covers them all.

      theorem Std.Internal.Do.Spec.foldM_iter {α β γ : Type u} {m : Type u → Type w} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] [Iterator α Id β] [Iterators.Finite α Id] [IteratorLoop α Id m] [LawfulIteratorLoop α Id m] {it : Iter β} {init : γ} {f : γβm γ} (inv : Invariant β γ Pred) {epost : EPred} (step : ∀ (pref : List β) (cur : β) (suff : List β), it.toList = pref ++ cur :: suff∀ (b : γ), inv pref (cur :: suff) b f b cur fun (b' : γ) => inv (pref ++ [cur]) suff b'; epost ) :
      inv [] it.toList init Iter.foldM f init it fun (b : γ) => inv it.toList [] b; epost
      theorem Std.Internal.Do.Spec.foldM_iterM_id {α β γ : Type u} {m : Type u → Type w} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] [Iterator α Id β] [Iterators.Finite α Id] [IteratorLoop α Id m] [LawfulIteratorLoop α Id m] {it : IterM Id β} {init : γ} {f : γβm γ} (inv : Invariant β γ Pred) {epost : EPred} (step : ∀ (pref : List β) (cur : β) (suff : List β), it.toList.run = pref ++ cur :: suff∀ (b : γ), inv pref (cur :: suff) b f b cur fun (b' : γ) => inv (pref ++ [cur]) suff b'; epost ) :
      inv [] it.toList.run init IterM.foldM f init it fun (b : γ) => inv it.toList.run [] b; epost
      theorem Std.Internal.Do.Spec.IterM.forIn_filterMapWithPostcondition {α β β₂ γ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {o : Type w → Type w'''} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [LawfulMonad m] [Monad n] [LawfulMonad n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [MonadLiftT m n] [LawfulMonadLiftT m n] [MonadLiftT n o] [LawfulMonadLiftT n o] [Iterator α m β] [Iterators.Finite α m] [IteratorLoop α m o] [LawfulIteratorLoop α m o] {it : IterM m β} {f : βIterators.PostconditionT n (Option β₂)} {init : γ} {g : β₂γo (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => do let __do_liftliftM (f out).run match __do_lift with | some c => g c acc | none => Pure.pure (ForInStep.yield acc) Q; eQ ) :
      theorem Std.Internal.Do.Spec.IterM.forIn_filterMapM {α β β₂ γ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {o : Type w → Type w'''} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [LawfulMonad m] [Monad n] [LawfulMonad n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [MonadAttach n] [WeaklyLawfulMonadAttach n] [MonadLiftT m n] [LawfulMonadLiftT m n] [MonadLiftT n o] [LawfulMonadLiftT n o] [Iterator α m β] [Iterators.Finite α m] [IteratorLoop α m o] [LawfulIteratorLoop α m o] {it : IterM m β} {f : βn (Option β₂)} {init : γ} {g : β₂γo (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => do let __do_liftliftM (f out) match __do_lift with | some c => g c acc | none => Pure.pure (ForInStep.yield acc) Q; eQ ) :
      P forIn (IterM.filterMapM f it) init g Q; eQ
      theorem Std.Internal.Do.Spec.IterM.forIn_filterMap {α β β₂ γ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [LawfulMonad m] [Monad n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [MonadLiftT m n] [LawfulMonadLiftT m n] [Iterator α m β] [Iterators.Finite α m] [IteratorLoop α m n] [LawfulIteratorLoop α m n] {it : IterM m β} {f : βOption β₂} {init : γ} {g : β₂γn (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => match f out with | some c => g c acc | none => Pure.pure (ForInStep.yield acc) Q; eQ ) :
      P forIn (IterM.filterMap f it) init g Q; eQ
      theorem Std.Internal.Do.Spec.IterM.forIn_mapWithPostcondition {α β β₂ γ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {o : Type w → Type w'''} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [LawfulMonad m] [Monad n] [LawfulMonad n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [MonadLiftT m n] [LawfulMonadLiftT m n] [MonadLiftT n o] [LawfulMonadLiftT n o] [Iterator α m β] [Iterators.Finite α m] [IteratorLoop α m o] [LawfulIteratorLoop α m o] {it : IterM m β} {f : βIterators.PostconditionT n β₂} {init : γ} {g : β₂γo (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => do let __do_liftliftM (f out).run g __do_lift acc Q; eQ ) :
      theorem Std.Internal.Do.Spec.IterM.forIn_mapM {α β β₂ γ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {o : Type w → Type w'''} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [LawfulMonad m] [Monad n] [LawfulMonad n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [MonadAttach n] [WeaklyLawfulMonadAttach n] [MonadLiftT m n] [LawfulMonadLiftT m n] [MonadLiftT n o] [LawfulMonadLiftT n o] [Iterator α m β] [Iterators.Finite α m] [IteratorLoop α m o] [LawfulIteratorLoop α m o] {it : IterM m β} {f : βn β₂} {init : γ} {g : β₂γo (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => do let __do_liftliftM (f out) g __do_lift acc Q; eQ ) :
      P forIn (IterM.mapM f it) init g Q; eQ
      theorem Std.Internal.Do.Spec.IterM.forIn_map {α β β₂ γ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [LawfulMonad m] [Monad n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [MonadLiftT m n] [LawfulMonadLiftT m n] [Iterator α m β] [Iterators.Finite α m] [IteratorLoop α m n] [LawfulIteratorLoop α m n] {it : IterM m β} {f : ββ₂} {init : γ} {g : β₂γn (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => g (f out) acc Q; eQ ) :
      P forIn (IterM.map f it) init g Q; eQ
      theorem Std.Internal.Do.Spec.IterM.forIn_filterWithPostcondition {α β γ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {o : Type w → Type w'''} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [LawfulMonad m] [Monad n] [LawfulMonad n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [MonadLiftT m n] [LawfulMonadLiftT m n] [MonadLiftT n o] [LawfulMonadLiftT n o] [Iterator α m β] [Iterators.Finite α m] [IteratorLoop α m o] [LawfulIteratorLoop α m o] {it : IterM m β} {f : βIterators.PostconditionT n (ULift Bool)} {init : γ} {g : βγo (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => do let __do_liftliftM (f out).run if __do_lift.down = true then g out acc else Pure.pure (ForInStep.yield acc) Q; eQ ) :
      theorem Std.Internal.Do.Spec.IterM.forIn_filterM {α β γ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {o : Type w → Type w'''} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [LawfulMonad m] [Monad n] [LawfulMonad n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [MonadAttach n] [WeaklyLawfulMonadAttach n] [MonadLiftT m n] [LawfulMonadLiftT m n] [MonadLiftT n o] [LawfulMonadLiftT n o] [Iterator α m β] [Iterators.Finite α m] [IteratorLoop α m o] [LawfulIteratorLoop α m o] {it : IterM m β} {f : βn (ULift Bool)} {init : γ} {g : βγo (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => do let __do_liftliftM (f out) if __do_lift.down = true then g out acc else Pure.pure (ForInStep.yield acc) Q; eQ ) :
      P forIn (IterM.filterM f it) init g Q; eQ
      theorem Std.Internal.Do.Spec.IterM.forIn_filter {α β γ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [LawfulMonad m] [Monad n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [MonadLiftT m n] [LawfulMonadLiftT m n] [Iterator α m β] [Iterators.Finite α m] [IteratorLoop α m n] [LawfulIteratorLoop α m n] {it : IterM m β} {f : βBool} {init : γ} {g : βγn (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => if f out = true then g out acc else Pure.pure (ForInStep.yield acc) Q; eQ ) :
      P forIn (IterM.filter f it) init g Q; eQ
      theorem Std.Internal.Do.Spec.IterM.foldM_filterMapWithPostcondition {α β γ δ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {o : Type w → Type w'''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [Monad n] [Monad o] [LawfulMonad m] [LawfulMonad n] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [IteratorLoop α m n] [IteratorLoop α m o] [LawfulIteratorLoop α m n] [LawfulIteratorLoop α m o] [MonadLiftT m n] [MonadLiftT n o] [LawfulMonadLiftT m n] [LawfulMonadLiftT n o] {f : βIterators.PostconditionT n (Option γ)} {g : δγo δ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.foldM (fun (d : δ) (b : β) => do let __xliftM (f b).run match __x with | some c => g d c | x => Pure.pure d) init it Q; eQ ) :
      theorem Std.Internal.Do.Spec.IterM.foldM_filterMapM {α β γ δ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {o : Type w → Type w'''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [LawfulMonad m] [Monad n] [MonadAttach n] [LawfulMonad n] [WeaklyLawfulMonadAttach n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [IteratorLoop α m n] [IteratorLoop α m o] [LawfulIteratorLoop α m n] [LawfulIteratorLoop α m o] [MonadLiftT m n] [MonadLiftT n o] [LawfulMonadLiftT m n] [LawfulMonadLiftT n o] {f : βn (Option γ)} {g : δγo δ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.foldM (fun (d : δ) (b : β) => do let __xliftM (f b) match __x with | some c => g d c | x => Pure.pure d) init it Q; eQ ) :
      theorem Std.Internal.Do.Spec.IterM.foldM_mapWithPostcondition {α β γ δ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {o : Type w → Type w'''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [Monad n] [Monad o] [LawfulMonad m] [LawfulMonad n] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [IteratorLoop α m n] [IteratorLoop α m o] [LawfulIteratorLoop α m n] [LawfulIteratorLoop α m o] [MonadLiftT m n] [MonadLiftT n o] [LawfulMonadLiftT m n] [LawfulMonadLiftT n o] {f : βIterators.PostconditionT n γ} {g : δγo δ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.foldM (fun (d : δ) (b : β) => do let cliftM (f b).run g d c) init it Q; eQ ) :
      theorem Std.Internal.Do.Spec.IterM.foldM_mapM {α β γ δ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {o : Type w → Type w'''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [LawfulMonad m] [Monad n] [MonadAttach n] [LawfulMonad n] [WeaklyLawfulMonadAttach n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [IteratorLoop α m n] [IteratorLoop α m o] [LawfulIteratorLoop α m n] [LawfulIteratorLoop α m o] [MonadLiftT m n] [MonadLiftT n o] [LawfulMonadLiftT m n] [LawfulMonadLiftT n o] {f : βn γ} {g : δγo δ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.foldM (fun (d : δ) (b : β) => do let cliftM (f b) g d c) init it Q; eQ ) :
      P IterM.foldM g init (IterM.mapM f it) Q; eQ
      theorem Std.Internal.Do.Spec.IterM.foldM_filterWithPostcondition {α β δ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {o : Type w → Type w'''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [Monad n] [Monad o] [LawfulMonad m] [LawfulMonad n] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [IteratorLoop α m n] [IteratorLoop α m o] [LawfulIteratorLoop α m n] [LawfulIteratorLoop α m o] [MonadLiftT m n] [MonadLiftT n o] [LawfulMonadLiftT m n] [LawfulMonadLiftT n o] {f : βIterators.PostconditionT n (ULift Bool)} {g : δβo δ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.foldM (fun (d : δ) (b : β) => do let __do_liftliftM (f b).run if __do_lift.down = true then g d b else Pure.pure d) init it Q; eQ ) :
      theorem Std.Internal.Do.Spec.IterM.foldM_filterM {α β δ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {o : Type w → Type w'''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [LawfulMonad m] [Monad n] [MonadAttach n] [LawfulMonad n] [WeaklyLawfulMonadAttach n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [IteratorLoop α m n] [IteratorLoop α m o] [LawfulIteratorLoop α m n] [LawfulIteratorLoop α m o] [MonadLiftT m n] [MonadLiftT n o] [LawfulMonadLiftT m n] [LawfulMonadLiftT n o] {f : βn (ULift Bool)} {g : δβo δ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.foldM (fun (d : δ) (b : β) => do let __do_liftliftM (f b) if __do_lift.down = true then g d b else Pure.pure d) init it Q; eQ ) :
      P IterM.foldM g init (IterM.filterM f it) Q; eQ
      theorem Std.Internal.Do.Spec.IterM.foldM_filterMap {α β γ δ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [Monad n] [LawfulMonad m] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α m n] [LawfulIteratorLoop α m n] [MonadLiftT m n] [LawfulMonadLiftT m n] {f : βOption γ} {g : δγn δ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.foldM (fun (d : δ) (b : β) => match f b with | some c => g d c | x => Pure.pure d) init it Q; eQ ) :
      P IterM.foldM g init (IterM.filterMap f it) Q; eQ
      theorem Std.Internal.Do.Spec.IterM.foldM_map {α β γ δ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [Monad n] [LawfulMonad m] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α m n] [LawfulIteratorLoop α m n] [MonadLiftT m n] [LawfulMonadLiftT m n] {f : βγ} {g : δγn δ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.foldM (fun (d : δ) (b : β) => g d (f b)) init it Q; eQ ) :
      P IterM.foldM g init (IterM.map f it) Q; eQ
      theorem Std.Internal.Do.Spec.IterM.foldM_filter {α β δ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [Monad n] [LawfulMonad m] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α m n] [LawfulIteratorLoop α m n] [MonadLiftT m n] [LawfulMonadLiftT m n] {f : βBool} {g : δβn δ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.foldM (fun (d : δ) (b : β) => if f b = true then g d b else Pure.pure d) init it Q; eQ ) :
      P IterM.foldM g init (IterM.filter f it) Q; eQ
      theorem Std.Internal.Do.Spec.IterM.fold_filterMapWithPostcondition {α β γ δ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [LawfulMonad m] [Monad n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α m n] [LawfulIteratorLoop α m n] [MonadLiftT m n] [LawfulMonadLiftT m n] {f : βIterators.PostconditionT n (Option γ)} {g : δγδ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.foldM (fun (d : δ) (b : β) => do let __x(f b).run match __x with | some c => Pure.pure (g d c) | x => Pure.pure d) init it Q; eQ ) :
      theorem Std.Internal.Do.Spec.IterM.fold_filterMapM {α β γ δ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [LawfulMonad m] [Monad n] [MonadAttach n] [WeaklyLawfulMonadAttach n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α m n] [LawfulIteratorLoop α m n] [MonadLiftT m n] [LawfulMonadLiftT m n] {f : βn (Option γ)} {g : δγδ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.foldM (fun (d : δ) (b : β) => do let __xf b match __x with | some c => Pure.pure (g d c) | x => Pure.pure d) init it Q; eQ ) :
      P IterM.fold g init (IterM.filterMapM f it) Q; eQ
      theorem Std.Internal.Do.Spec.IterM.fold_mapWithPostcondition {α β γ δ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [LawfulMonad m] [Monad n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α m n] [LawfulIteratorLoop α m n] [MonadLiftT m n] [LawfulMonadLiftT m n] {f : βIterators.PostconditionT n γ} {g : δγδ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.foldM (fun (d : δ) (b : β) => do let c(f b).run Pure.pure (g d c)) init it Q; eQ ) :
      theorem Std.Internal.Do.Spec.IterM.fold_mapM {α β γ δ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [LawfulMonad m] [Monad n] [MonadAttach n] [WeaklyLawfulMonadAttach n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α m n] [LawfulIteratorLoop α m n] [MonadLiftT m n] [LawfulMonadLiftT m n] {f : βn γ} {g : δγδ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.foldM (fun (d : δ) (b : β) => do let cf b Pure.pure (g d c)) init it Q; eQ ) :
      P IterM.fold g init (IterM.mapM f it) Q; eQ
      theorem Std.Internal.Do.Spec.IterM.fold_filterWithPostcondition {α β δ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [LawfulMonad m] [Monad n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α m n] [LawfulIteratorLoop α m n] [MonadLiftT m n] [LawfulMonadLiftT m n] {f : βIterators.PostconditionT n (ULift Bool)} {g : δβδ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.foldM (fun (d : δ) (b : β) => do let __do_lift(f b).run Pure.pure (if __do_lift.down = true then g d b else d)) init it Q; eQ ) :
      theorem Std.Internal.Do.Spec.IterM.fold_filterM {α β δ : Type w} {m : Type w → Type w'} {n : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [LawfulMonad m] [Monad n] [MonadAttach n] [WeaklyLawfulMonadAttach n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α m n] [LawfulIteratorLoop α m n] [MonadLiftT m n] [LawfulMonadLiftT m n] {f : βn (ULift Bool)} {g : δβδ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.foldM (fun (d : δ) (b : β) => do let __do_liftf b Pure.pure (if __do_lift.down = true then g d b else d)) init it Q; eQ ) :
      P IterM.fold g init (IterM.filterM f it) Q; eQ
      theorem Std.Internal.Do.Spec.IterM.fold_filterMap {α β γ δ : Type w} {m : Type w → Type w'} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] [IteratorLoop α m m] [LawfulIteratorLoop α m m] {f : βOption γ} {g : δγδ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.fold (fun (d : δ) (b : β) => match f b with | some c => g d c | x => d) init it Q; eQ ) :
      P IterM.fold g init (IterM.filterMap f it) Q; eQ
      theorem Std.Internal.Do.Spec.IterM.fold_map {α β γ δ : Type w} {m : Type w → Type w'} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] [IteratorLoop α m m] [LawfulIteratorLoop α m m] {f : βγ} {g : δγδ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.fold (fun (d : δ) (b : β) => g d (f b)) init it Q; eQ ) :
      P IterM.fold g init (IterM.map f it) Q; eQ
      theorem Std.Internal.Do.Spec.IterM.fold_filter {α β δ : Type w} {m : Type w → Type w'} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α m β] [Iterators.Finite α m] [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] [IteratorLoop α m m] [LawfulIteratorLoop α m m] {f : βBool} {g : δβδ} {init : δ} {it : IterM m β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P IterM.fold (fun (d : δ) (b : β) => if f b = true then g d b else d) init it Q; eQ ) :
      P IterM.fold g init (IterM.filter f it) Q; eQ
      theorem Std.Internal.Do.Spec.Iter.forIn_filterMapWithPostcondition {α β β₂ γ : Type w} {n : Type w → Type w'} {o : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Monad n] [LawfulMonad n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [MonadLiftT n o] [LawfulMonadLiftT n o] [Iterators.Finite α Id] [IteratorLoop α Id o] [LawfulIteratorLoop α Id o] {it : Iter β} {f : βIterators.PostconditionT n (Option β₂)} {init : γ} {g : β₂γo (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => do let __do_liftliftM (f out).run match __do_lift with | some c => g c acc | none => Pure.pure (ForInStep.yield acc) Q; eQ ) :
      theorem Std.Internal.Do.Spec.Iter.forIn_filterMapM {α β β₂ γ : Type w} {n : Type w → Type w'} {o : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Monad n] [LawfulMonad n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [MonadAttach n] [WeaklyLawfulMonadAttach n] [MonadLiftT n o] [LawfulMonadLiftT n o] [Iterators.Finite α Id] [IteratorLoop α Id o] [LawfulIteratorLoop α Id o] {it : Iter β} {f : βn (Option β₂)} {init : γ} {g : β₂γo (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => do let __do_liftliftM (f out) match __do_lift with | some c => g c acc | none => Pure.pure (ForInStep.yield acc) Q; eQ ) :
      P forIn (Iter.filterMapM f it) init g Q; eQ
      theorem Std.Internal.Do.Spec.Iter.forIn_filterMap {α β β₂ γ : Type w} {n : Type w → Type w'} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Monad n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [Iterators.Finite α Id] [IteratorLoop α Id n] [LawfulIteratorLoop α Id n] {it : Iter β} {f : βOption β₂} {init : γ} {g : β₂γn (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => match f out with | some c => g c acc | none => Pure.pure (ForInStep.yield acc) Q; eQ ) :
      P forIn (Iter.filterMap f it) init g Q; eQ
      theorem Std.Internal.Do.Spec.Iter.forIn_mapWithPostcondition {α β β₂ γ : Type w} {n : Type w → Type w'} {o : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Monad n] [LawfulMonad n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [MonadLiftT n o] [LawfulMonadLiftT n o] [Iterators.Finite α Id] [IteratorLoop α Id o] [LawfulIteratorLoop α Id o] {it : Iter β} {f : βIterators.PostconditionT n β₂} {init : γ} {g : β₂γo (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => do let __do_liftliftM (f out).run g __do_lift acc Q; eQ ) :
      theorem Std.Internal.Do.Spec.Iter.forIn_mapM {α β β₂ γ : Type w} {n : Type w → Type w'} {o : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Monad n] [LawfulMonad n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [MonadAttach n] [WeaklyLawfulMonadAttach n] [MonadLiftT n o] [LawfulMonadLiftT n o] [Iterators.Finite α Id] [IteratorLoop α Id o] [LawfulIteratorLoop α Id o] {it : Iter β} {f : βn β₂} {init : γ} {g : β₂γo (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => do let __do_liftliftM (f out) g __do_lift acc Q; eQ ) :
      P forIn (Iter.mapM f it) init g Q; eQ
      theorem Std.Internal.Do.Spec.Iter.forIn_map {α β β₂ γ : Type w} {n : Type w → Type w'} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Monad n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [Iterators.Finite α Id] [IteratorLoop α Id n] [LawfulIteratorLoop α Id n] {it : Iter β} {f : ββ₂} {init : γ} {g : β₂γn (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => g (f out) acc Q; eQ ) :
      P forIn (Iter.map f it) init g Q; eQ
      theorem Std.Internal.Do.Spec.Iter.forIn_filterWithPostcondition {α β γ : Type w} {n : Type w → Type w'} {o : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Monad n] [LawfulMonad n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [MonadLiftT n o] [LawfulMonadLiftT n o] [Iterators.Finite α Id] [IteratorLoop α Id o] [LawfulIteratorLoop α Id o] {it : Iter β} {f : βIterators.PostconditionT n (ULift Bool)} {init : γ} {g : βγo (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => do let __do_liftliftM (f out).run if __do_lift.down = true then g out acc else Pure.pure (ForInStep.yield acc) Q; eQ ) :
      theorem Std.Internal.Do.Spec.Iter.forIn_filterM {α β γ : Type w} {n : Type w → Type w'} {o : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Monad n] [LawfulMonad n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [MonadAttach n] [WeaklyLawfulMonadAttach n] [MonadLiftT n o] [LawfulMonadLiftT n o] [Iterators.Finite α Id] [IteratorLoop α Id o] [LawfulIteratorLoop α Id o] {it : Iter β} {f : βn (ULift Bool)} {init : γ} {g : βγo (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => do let __do_liftliftM (f out) if __do_lift.down = true then g out acc else Pure.pure (ForInStep.yield acc) Q; eQ ) :
      P forIn (Iter.filterM f it) init g Q; eQ
      theorem Std.Internal.Do.Spec.Iter.forIn_filter {α β γ : Type w} {n : Type w → Type w'} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Monad n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [Iterators.Finite α Id] [IteratorLoop α Id n] [LawfulIteratorLoop α Id n] {it : Iter β} {f : βBool} {init : γ} {g : βγn (ForInStep γ)} {P : Pred} {Q : γPred} {eQ : EPred} (h : P forIn it init fun (out : β) (acc : γ) => if f out = true then g out acc else Pure.pure (ForInStep.yield acc) Q; eQ ) :
      P forIn (Iter.filter f it) init g Q; eQ
      theorem Std.Internal.Do.Spec.Iter.foldM_filterMapWithPostcondition {α β γ δ : Type w} {n : Type w → Type w'} {o : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Iterators.Finite α Id] [Monad n] [Monad o] [LawfulMonad n] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [IteratorLoop α Id n] [IteratorLoop α Id o] [LawfulIteratorLoop α Id n] [LawfulIteratorLoop α Id o] [MonadLiftT n o] [LawfulMonadLiftT n o] {f : βIterators.PostconditionT n (Option γ)} {g : δγo δ} {init : δ} {it : Iter β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P Iter.foldM (fun (d : δ) (b : β) => do let __xliftM (f b).run match __x with | some c => g d c | x => Pure.pure d) init it Q; eQ ) :
      theorem Std.Internal.Do.Spec.Iter.foldM_filterMapM {α β γ δ : Type w} {n : Type w → Type w'} {o : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Iterators.Finite α Id] [Monad n] [MonadAttach n] [LawfulMonad n] [WeaklyLawfulMonadAttach n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [IteratorLoop α Id n] [IteratorLoop α Id o] [LawfulIteratorLoop α Id n] [LawfulIteratorLoop α Id o] [MonadLiftT n o] [LawfulMonadLiftT n o] {f : βn (Option γ)} {g : δγo δ} {init : δ} {it : Iter β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P Iter.foldM (fun (d : δ) (b : β) => do let __xliftM (f b) match __x with | some c => g d c | x => Pure.pure d) init it Q; eQ ) :
      P IterM.foldM g init (Iter.filterMapM f it) Q; eQ
      theorem Std.Internal.Do.Spec.Iter.foldM_mapWithPostcondition {α β γ δ : Type w} {m : Type w → Type w'''} {n : Type w → Type w'} {o : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Iterators.Finite α Id] [Monad m] [Monad n] [Monad o] [LawfulMonad m] [LawfulMonad n] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [IteratorLoop α Id n] [IteratorLoop α Id o] [LawfulIteratorLoop α Id n] [LawfulIteratorLoop α Id o] [MonadLiftT n o] [LawfulMonadLiftT n o] {f : βIterators.PostconditionT n γ} {g : δγo δ} {init : δ} {it : Iter β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P Iter.foldM (fun (d : δ) (b : β) => do let cliftM (f b).run g d c) init it Q; eQ ) :
      theorem Std.Internal.Do.Spec.Iter.foldM_mapM {α β γ δ : Type w} {n : Type w → Type w'} {o : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Iterators.Finite α Id] [Monad n] [MonadAttach n] [LawfulMonad n] [WeaklyLawfulMonadAttach n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [IteratorLoop α Id n] [IteratorLoop α Id o] [LawfulIteratorLoop α Id n] [LawfulIteratorLoop α Id o] [MonadLiftT n o] [LawfulMonadLiftT n o] {f : βn γ} {g : δγo δ} {init : δ} {it : Iter β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P Iter.foldM (fun (d : δ) (b : β) => do let cliftM (f b) g d c) init it Q; eQ ) :
      P IterM.foldM g init (Iter.mapM f it) Q; eQ
      theorem Std.Internal.Do.Spec.Iter.foldM_filterWithPostcondition {α β δ : Type w} {n : Type w → Type w'} {o : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Iterators.Finite α Id] [Monad n] [Monad o] [LawfulMonad n] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [IteratorLoop α Id n] [IteratorLoop α Id o] [LawfulIteratorLoop α Id n] [LawfulIteratorLoop α Id o] [MonadLiftT n o] [LawfulMonadLiftT n o] {f : βIterators.PostconditionT n (ULift Bool)} {g : δβo δ} {init : δ} {it : Iter β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P Iter.foldM (fun (d : δ) (b : β) => do let __do_liftliftM (f b).run if __do_lift.down = true then g d b else Pure.pure d) init it Q; eQ ) :
      theorem Std.Internal.Do.Spec.Iter.foldM_filterM {α β δ : Type w} {n : Type w → Type w'} {o : Type w → Type w''} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Iterators.Finite α Id] [Monad n] [MonadAttach n] [LawfulMonad n] [WeaklyLawfulMonadAttach n] [Monad o] [Assertion Pred] [Assertion EPred] [WPMonad o Pred EPred] [IteratorLoop α Id n] [IteratorLoop α Id o] [LawfulIteratorLoop α Id n] [LawfulIteratorLoop α Id o] [MonadLiftT n o] [LawfulMonadLiftT n o] {f : βn (ULift Bool)} {g : δβo δ} {init : δ} {it : Iter β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P Iter.foldM (fun (d : δ) (b : β) => do let __do_liftliftM (f b) if __do_lift.down = true then g d b else Pure.pure d) init it Q; eQ ) :
      P IterM.foldM g init (Iter.filterM f it) Q; eQ
      theorem Std.Internal.Do.Spec.Iter.foldM_filterMap {α β γ δ : Type w} {n : Type w → Type w'} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Iterators.Finite α Id] [Monad n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α Id n] [LawfulIteratorLoop α Id n] {f : βOption γ} {g : δγn δ} {init : δ} {it : Iter β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P Iter.foldM (fun (d : δ) (b : β) => match f b with | some c => g d c | x => Pure.pure d) init it Q; eQ ) :
      P Iter.foldM g init (Iter.filterMap f it) Q; eQ
      theorem Std.Internal.Do.Spec.Iter.foldM_map {α β γ δ : Type w} {n : Type w → Type w'} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Iterators.Finite α Id] [Monad n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α Id n] [LawfulIteratorLoop α Id n] {f : βγ} {g : δγn δ} {init : δ} {it : Iter β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P Iter.foldM (fun (d : δ) (b : β) => g d (f b)) init it Q; eQ ) :
      P Iter.foldM g init (Iter.map f it) Q; eQ
      theorem Std.Internal.Do.Spec.Iter.foldM_filter {α β δ : Type w} {n : Type w → Type w'} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Iterators.Finite α Id] [Monad n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α Id n] [LawfulIteratorLoop α Id n] {f : βBool} {g : δβn δ} {init : δ} {it : Iter β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P Iter.foldM (fun (d : δ) (b : β) => if f b = true then g d b else Pure.pure d) init it Q; eQ ) :
      P Iter.foldM g init (Iter.filter f it) Q; eQ
      theorem Std.Internal.Do.Spec.Iter.fold_filterMapWithPostcondition {α β γ δ : Type w} {n : Type w → Type w'} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Iterators.Finite α Id] [Monad n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α Id n] [LawfulIteratorLoop α Id n] {f : βIterators.PostconditionT n (Option γ)} {g : δγδ} {init : δ} {it : Iter β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P Iter.foldM (fun (d : δ) (b : β) => do let __x(f b).run match __x with | some c => Pure.pure (g d c) | x => Pure.pure d) init it Q; eQ ) :
      theorem Std.Internal.Do.Spec.Iter.fold_filterMapM {α β γ δ : Type w} {n : Type w → Type w'} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Iterators.Finite α Id] [Monad n] [MonadAttach n] [WeaklyLawfulMonadAttach n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α Id n] [LawfulIteratorLoop α Id n] {f : βn (Option γ)} {g : δγδ} {init : δ} {it : Iter β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P Iter.foldM (fun (d : δ) (b : β) => do let __xf b match __x with | some c => Pure.pure (g d c) | x => Pure.pure d) init it Q; eQ ) :
      P IterM.fold g init (Iter.filterMapM f it) Q; eQ
      theorem Std.Internal.Do.Spec.Iter.fold_mapWithPostcondition {α β γ δ : Type w} {n : Type w → Type w'} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Iterators.Finite α Id] [Monad n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α Id n] [LawfulIteratorLoop α Id n] {f : βIterators.PostconditionT n γ} {g : δγδ} {init : δ} {it : Iter β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P Iter.foldM (fun (d : δ) (b : β) => do let c(f b).run Pure.pure (g d c)) init it Q; eQ ) :
      theorem Std.Internal.Do.Spec.Iter.fold_mapM {α β γ δ : Type w} {n : Type w → Type w'} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Iterators.Finite α Id] [Monad n] [MonadAttach n] [WeaklyLawfulMonadAttach n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α Id n] [LawfulIteratorLoop α Id n] {f : βn γ} {g : δγδ} {init : δ} {it : Iter β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P Iter.foldM (fun (d : δ) (b : β) => do let cf b Pure.pure (g d c)) init it Q; eQ ) :
      P IterM.fold g init (Iter.mapM f it) Q; eQ
      theorem Std.Internal.Do.Spec.Iter.fold_filterWithPostcondition {α β δ : Type w} {n : Type w → Type w'} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Iterators.Finite α Id] [Monad n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α Id n] [LawfulIteratorLoop α Id n] {f : βIterators.PostconditionT n (ULift Bool)} {g : δβδ} {init : δ} {it : Iter β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P Iter.foldM (fun (d : δ) (b : β) => do let __do_lift(f b).run Pure.pure (if __do_lift.down = true then g d b else d)) init it Q; eQ ) :
      theorem Std.Internal.Do.Spec.Iter.fold_filterM {α β δ : Type w} {n : Type w → Type w'} {Pred : Type uₚ} {EPred : Type uₑ} [Iterator α Id β] [Iterators.Finite α Id] [Monad n] [MonadAttach n] [WeaklyLawfulMonadAttach n] [Assertion Pred] [Assertion EPred] [WPMonad n Pred EPred] [IteratorLoop α Id n] [LawfulIteratorLoop α Id n] {f : βn (ULift Bool)} {g : δβδ} {init : δ} {it : Iter β} {P : Pred} {Q : δPred} {eQ : EPred} (h : P Iter.foldM (fun (d : δ) (b : β) => do let __do_liftf b Pure.pure (if __do_lift.down = true then g d b else d)) init it Q; eQ ) :
      P IterM.fold g init (Iter.filterM f it) Q; eQ
      theorem Std.Internal.Do.Spec.foldlM_array {α : Type u₁} {β : Type u₂} {m : Type u₂ → Type v} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {xs : Array α} {init : β} {f : βαm β} (inv : Invariant α β Pred) {epost : EPred} (step : ∀ (pref : List α) (cur : α) (suff : List α), xs.toList = pref ++ cur :: suff∀ (b : β), inv pref (cur :: suff) b f b cur fun (b' : β) => inv (pref ++ [cur]) suff b'; epost ) :
      inv [] xs.toList init Array.foldlM f init xs fun (b : β) => inv xs.toList [] b; epost
      def Std.Internal.Do.StringInvariant (s : String) (β : Type u) (Pred : Type uₚ) :
      Type (max u uₚ)

      The type of loop invariants used by the specifications of for ... in ... loops over strings. A loop invariant is a function mapping the current position and state to a lattice element.

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      Instances For
        @[reducible, inline]
        noncomputable abbrev Std.Internal.Do.StringInvariant.withEarlyReturnNewDo {s : String} {β γ : Type u} (Pred : Type uₚ) [Assertion Pred] (onContinue : s.PosβPred) (onReturn : γβPred) :
        StringInvariant s (Option γ × β) Pred

        An invariant combinator for String loops with early return, for the new do elaborator which uses Prod for the state tuple: onContinue is the invariant while iterating, onReturn holds once the loop returned early with a value.

        Equations
        • One or more equations did not get rendered due to their size.
        Instances For
          theorem Std.Internal.Do.Spec.forIn_string {β : Type u₂} {m : Type u₂ → Type v} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {s : String} {init : β} {f : Charβm (ForInStep β)} (inv : StringInvariant s β Pred) {epost : EPred} (step : ∀ (pos : s.Pos) (b : β) (h : pos s.endPos), inv pos b f (pos.get h) b fun (r : ForInStep β) => match r with | ForInStep.yield b' => inv (pos.next h) b' | ForInStep.done b' => inv s.endPos b'; epost ) :
          inv s.startPos init forIn s init f fun (b : β) => inv s.endPos b; epost
          def Std.Internal.Do.StringSliceInvariant (s : String.Slice) (β : Type u) (Pred : Type uₚ) :
          Type (max u uₚ)

          The type of loop invariants used by the specifications of for ... in ... loops over string slices. A loop invariant is a function mapping the current position and state to a lattice element.

          Equations
          Instances For
            @[reducible, inline]
            noncomputable abbrev Std.Internal.Do.StringSliceInvariant.withEarlyReturnNewDo {s : String.Slice} {β γ : Type u} (Pred : Type uₚ) [Assertion Pred] (onContinue : s.PosβPred) (onReturn : γβPred) :

            An invariant combinator for String.Slice loops with early return, for the new do elaborator which uses Prod for the state tuple: onContinue is the invariant while iterating, onReturn holds once the loop returned early with a value.

            Equations
            • One or more equations did not get rendered due to their size.
            Instances For
              theorem Std.Internal.Do.Spec.forIn_stringSlice {β : Type u₂} {m : Type u₂ → Type v} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {s : String.Slice} {init : β} {f : Charβm (ForInStep β)} (inv : StringSliceInvariant s β Pred) {epost : EPred} (step : ∀ (pos : s.Pos) (b : β) (h : pos s.endPos), inv pos b f (pos.get h) b fun (r : ForInStep β) => match r with | ForInStep.yield b' => inv (pos.next h) b' | ForInStep.done b' => inv s.endPos b'; epost ) :
              inv s.startPos init forIn s init f fun (b : β) => inv s.endPos b; epost
              def Std.Internal.Do.RepeatInvariant (α β : Type u) (Pred : Type uₚ) :
              Type (max uₚ u)

              An invariant for a repeatM loop, given as a predicate over the α ⊕ β cursor: .inl a is the continue case at a; .inr b is the break case with result b.

              Equations
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                structure Std.Internal.Do.RepeatVariant (α : Type uα) (Pred : Type u) [Assertion Pred] :
                Type (max uα (uγ + 1) u)

                A termination measure for a repeatM loop: a type γ of measure values equipped with a well-founded relation, and a lattice-embedded evaluation of the measure at each cursor. Build one from a measure function with RepeatVariant.ofMeasure.

                • γ : Type

                  The type of measure values.

                • wfRel : WellFoundedRelation self.γ

                  The well-founded relation that measure values decrease along.

                • EvalsTo : αself.γPred

                  Relates the measure at cursor a to a value n inside the assertion lattice.

                • total (a : α) : (Lean.Order.iSup fun (n : self.γ) => self.EvalsTo a n) = Lean.Order.top

                  The measure evaluates to some value.

                Instances For
                  def Std.Internal.Do.RepeatVariant.rel {Pred : Type uₚ} [Assertion Pred] {α : Type uα} (v : RepeatVariant α Pred) :
                  v.γv.γProp

                  The relation that measure values decrease along.

                  Equations
                  Instances For
                    theorem Std.Internal.Do.RepeatVariant.wf {Pred : Type uₚ} [Assertion Pred] {α : Type uα} (v : RepeatVariant α Pred) :

                    Eliminate the covering join of EvalsTo from the left of an entailment.

                    @[instance_reducible]
                    def Std.Internal.Do.RepeatVariant.ofMeasure {Pred : Type uₚ} [Assertion Pred] {α : Type uα} {γ : Type uγ} {Fun : Type v'} [Assertion.NondetFun Pred Fun γ] [WellFoundedRelation γ] (f : αFun) :

                    Build a RepeatVariant from a measure function f. The measure's value type γ (its codomain through any NondetFun state layers) provides the well-founded relation, e.g. < for Nat and the lexicographic order for products.

                    Equations
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                      @[simp]
                      theorem Std.Internal.Do.RepeatVariant.γ_ofMeasure {Pred : Type uₚ} [Assertion Pred] {α : Type uα} {γ : Type uγ} {Fun : Type v'} [Assertion.NondetFun Pred Fun γ] [WellFoundedRelation γ] (f : αFun) :
                      (ofMeasure f).γ = γ
                      @[simp]
                      theorem Std.Internal.Do.RepeatVariant.evalsTo_ofMeasure {Pred : Type uₚ} [Assertion Pred] {α : Type uα} {γ : Type uγ} {Fun : Type v'} [Assertion.NondetFun Pred Fun γ] [WellFoundedRelation γ] (f : αFun) (a : α) (n : γ) :
                      theorem Std.Internal.Do.RepeatVariant.rel_ofMeasure {Pred : Type uₚ} [Assertion Pred] {α : Type uα} {γ : Type uγ} {Fun : Type v'} [Assertion.NondetFun Pred Fun γ] [WellFoundedRelation γ] (f : αFun) (n' n : γ) :

                      Decrease along ofMeasure is decrease of measure values along the well-founded relation of γ. Rewriting with this lemma brings a decrease proof obligation into the shape produced by termination_by, so that decreasing_tactic applies.

                      @[simp]
                      theorem Std.Internal.Do.RepeatVariant.rel_ofMeasure_nat {α Pred : Type} [Assertion Pred] {Fun : Type} [Assertion.NondetFun Pred Fun Nat] (f : αFun) (n' n : Nat) :
                      (ofMeasure f).rel n' n n' < n
                      noncomputable def Std.Internal.Do.RepeatVariant.EvalsBelow {Pred : Type uₚ} [Assertion Pred] {α : Type uα} (v : RepeatVariant α Pred) (a' : α) (ma : v.γ) :
                      Pred

                      The measure at cursor a' evaluates to a value strictly below ma.

                      Equations
                      Instances For
                        theorem Std.Internal.Do.RepeatVariant.evalsBelow_ofMeasure {Pred : Type uₚ} [Assertion Pred] {α : Type uα} {γ : Type uγ} [WellFoundedRelation γ] (f : αγ) (a' : α) (ma : γ) :

                        For a state-independent measure the pinned value is the measure itself, so the join collapses to a decrease along the well-founded relation of γ. The proof obligation has the shape produced by termination_by, so that decreasing_tactic applies.

                        @[simp]
                        theorem Std.Internal.Do.RepeatVariant.evalsBelow_ofMeasure_nat {α Pred : Type} [Assertion Pred] (f : αNat) (a' : α) (ma : Nat) :
                        @[simp]
                        theorem Std.Internal.Do.RepeatVariant.evalsBelow_ofMeasure_apply {α : Type uα} {σ : Type s} {Pred : Type u} [Assertion Pred] {γ : Type uγ} {Fun : Type v'} [Assertion.NondetFun Pred Fun γ] [WellFoundedRelation γ] (f : ασFun) (a' : α) (ma : γ) (s : σ) :
                        (ofMeasure f).EvalsBelow a' ma s = (ofMeasure fun (x : α) => f x s).EvalsBelow a' ma

                        Pointwise characterization of EvalsBelow on a function lattice, for ofMeasure measures.

                        Fixed-arity specializations of evalsBelow_ofMeasure_apply for Nat-valued measures at a lattice tower ending in Prop, in the manner of CompleteLattice.ofProp_apply_1 and its siblings: the ground instances leave every parameter recoverable from the trigger, so these are usable @[grind =] lemmas where the general evalsBelow_ofMeasure_apply is not.

                        theorem Std.Internal.Do.RepeatVariant.evalsBelow_ofMeasure_apply_1 {α σ₁ : Type} (f : ασ₁Nat) (a' : α) (ma : Nat) (s₁ : σ₁) :
                        (ofMeasure f).EvalsBelow a' ma s₁ = (f a' s₁ < ma)
                        theorem Std.Internal.Do.RepeatVariant.evalsBelow_ofMeasure_apply_2 {α σ₁ σ₂ : Type} (f : ασ₁σ₂Nat) (a' : α) (ma : Nat) (s₁ : σ₁) (s₂ : σ₂) :
                        (ofMeasure f).EvalsBelow a' ma s₁ s₂ = (f a' s₁ s₂ < ma)
                        theorem Std.Internal.Do.RepeatVariant.evalsBelow_ofMeasure_apply_3 {α σ₁ σ₂ σ₃ : Type} (f : ασ₁σ₂σ₃Nat) (a' : α) (ma : Nat) (s₁ : σ₁) (s₂ : σ₂) (s₃ : σ₃) :
                        (ofMeasure f).EvalsBelow a' ma s₁ s₂ s₃ = (f a' s₁ s₂ s₃ < ma)
                        theorem Std.Internal.Do.RepeatVariant.evalsBelow_ofMeasure_apply_4 {α σ₁ σ₂ σ₃ σ₄ : Type} (f : ασ₁σ₂σ₃σ₄Nat) (a' : α) (ma : Nat) (s₁ : σ₁) (s₂ : σ₂) (s₃ : σ₃) (s₄ : σ₄) :
                        (ofMeasure f).EvalsBelow a' ma s₁ s₂ s₃ s₄ = (f a' s₁ s₂ s₃ s₄ < ma)
                        theorem Std.Internal.Do.RepeatVariant.evalsBelow_ofMeasure_apply_5 {α σ₁ σ₂ σ₃ σ₄ σ₅ : Type} (f : ασ₁σ₂σ₃σ₄σ₅Nat) (a' : α) (ma : Nat) (s₁ : σ₁) (s₂ : σ₂) (s₃ : σ₃) (s₄ : σ₄) (s₅ : σ₅) :
                        (ofMeasure f).EvalsBelow a' ma s₁ s₂ s₃ s₄ s₅ = (f a' s₁ s₂ s₃ s₄ s₅ < ma)
                        theorem Std.Internal.Do.Spec.repeatM {α β : Type u} {m : Type u → Type v} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [Lean.Order.MonadTail m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {init : α} {f : αm (α β)} [Nonempty β] [∀ (P : Pred), Lean.Order.PreservesSup (Lean.Order.meet P)] (measure : RepeatVariant α Pred) (inv : RepeatInvariant α β Pred) (einv : EPred) (step : ∀ (a : α) (ma : measure.γ), Lean.Order.meet (measure.EvalsTo a ma) (inv (Sum.inl a)) f a fun (r : α β) => match r with | Sum.inl a' => Lean.Order.meet (measure.EvalsBelow a' ma) (inv (Sum.inl a')) | Sum.inr b => inv (Sum.inr b); einv ) :
                        inv (Sum.inl init) _root_.repeatM f init fun (b : β) => inv (Sum.inr b); einv

                        Specification for repeatM. The user supplies a termination measure, an invariant, and a step Triple whose pre asserts the measure evaluates to ma and the in-progress invariant holds, and whose post either continues with a measure value below ma (the invariant still holding) or finishes with the .inr invariant.

                        @[reducible, inline]
                        noncomputable abbrev Std.Internal.Do.RepeatInvariant.ofInvariantAndBreak {α Pred : Type u} [Assertion Pred] (inv onBreak : αPred) :
                        RepeatInvariant α α Pred

                        Construct an invariant from a loop invariant inv and a break condition onBreak.

                        inv holds at the end of every loop iteration (including the breaking one), and onBreak holds in addition to inv once the loop is done. For a normal while loop onBreak can be taken as the negation of the loop condition.

                        Equations
                        Instances For
                          theorem Std.Internal.Do.Spec.forIn_loop {β : Type u} {m : Type u → Type v} {Pred : Type uₚ} {EPred : Type uₑ} [Monad m] [Lean.Order.MonadTail m] [Assertion Pred] [Assertion EPred] [WPMonad m Pred EPred] {l : Lean.Loop} {init : β} {f : Unitβm (ForInStep β)} [∀ (P : Pred), Lean.Order.PreservesSup (Lean.Order.meet P)] (measure : RepeatVariant β Pred) (inv : RepeatInvariant β β Pred) (einv : EPred) (step : ∀ (b : β) (mb : measure.γ), Lean.Order.meet (measure.EvalsTo b mb) (inv (Sum.inl b)) f () b fun (r : ForInStep β) => match r with | ForInStep.yield b' => Lean.Order.meet (measure.EvalsBelow b' mb) (inv (Sum.inl b')) | ForInStep.done b' => inv (Sum.inr b'); einv ) :
                          inv (Sum.inl init) forIn l init f fun (b : β) => inv (Sum.inr b); einv

                          Specification for forIn over a Lean.Loop. The cursor is β ⊕ β: .inl b means "still iterating with b", .inr b means "finished with result b".