Similar to MonadState, but it retrieves/restores only the "backtrackable" part of the state
- saveState : m s
- restoreState : s → m Unit
Instances
def
Lean.commitWhenSome?
{m : Type → Type}
{s : Type}
{ε : Type u_1}
{α : Type}
[Monad m]
[Lean.MonadBacktrack s m]
[MonadExcept ε m]
(x? : m (Option α))
:
m (Option α)
Execute x?, but backtrack state if result is none or an exception was thrown.
Instances For
def
Lean.commitWhenSomeNoEx?
{m : Type → Type}
{s : Type}
{ε : Type u_1}
{α : Type}
[Monad m]
[Lean.MonadBacktrack s m]
[MonadExcept ε m]
(x? : m (Option α))
:
m (Option α)
Execute x?, but backtrack state if result is none or an exception was thrown.
If an exception is thrown, none is returned.
That is, this function is similar to commitWhenSome?, but swallows the exception and returns none.
Equations
- One or more equations did not get rendered due to their size.
Instances For
def
Lean.commitWhen
{m : Type → Type}
{s : Type}
{ε : Type u_1}
[Monad m]
[Lean.MonadBacktrack s m]
[MonadExcept ε m]
(x : m Bool)
:
m Bool
Equations
- One or more equations did not get rendered due to their size.
Instances For
def
Lean.commitIfNoEx
{m : Type → Type}
{s : Type}
{ε : Type u_1}
{α : Type}
[Monad m]
[Lean.MonadBacktrack s m]
[MonadExcept ε m]
(x : m α)
:
m α
Equations
- Lean.commitIfNoEx x = do let s_1 ← Lean.saveState tryCatch x fun (ex : ε) => do Lean.restoreState s_1 throw ex
Instances For
def
Lean.withoutModifyingState
{m : Type → Type}
{s α : Type}
[Monad m]
[MonadFinally m]
[Lean.MonadBacktrack s m]
(x : m α)
:
m α
Instances For
def
Lean.observing?
{m : Type → Type}
{s : Type}
{ε : Type u_1}
{α : Type}
[Monad m]
[Lean.MonadBacktrack s m]
[MonadExcept ε m]
(x : m α)
:
m (Option α)
Equations
- One or more equations did not get rendered due to their size.
Instances For
instance
Lean.instMonadBacktrackExceptTOfMonad
{s : Type}
{m : Type → Type}
{ε : Type}
[Lean.MonadBacktrack s m]
[Monad m]
:
Lean.MonadBacktrack s (ExceptT ε m)
Equations
- Lean.instMonadBacktrackExceptTOfMonad = { saveState := ExceptT.lift Lean.saveState, restoreState := fun (s_1 : s) => ExceptT.lift (Lean.restoreState s_1) }