Struct MutateContext 

pub struct MutateContext<'a, State, Driver: ?Sized = dyn MutateContextDriver<State> + 'a> { /* private fields */ }

State and recursive operations available to a callback-chain mutation.

A matched callback owns mutation of its value. Recursive operations reborrow the mutator, so mutable state cannot remain borrowed across them.

Implementations

impl<State, Driver> MutateContext<'_, State, Driver>

where Driver: MutateContextDriver<State> + ?Sized,

pub fn state(&self) -> &State

User state shared by every callback in this mutation.

pub fn state_mut(&mut self) -> &mut State

Mutably borrow the user state.

pub fn current(&self) -> &MapValue

Complete borrowed value active at this callback.

pub fn def_region_kind(&self) -> DefRegionKind

Definition-region state active at the callback’s current value.

pub fn region(&self) -> DefRegionKind

Definition region active at the callback’s current value.

pub fn mutate<T>(&mut self, value: &T) -> Result<Any>

where for<'x> AnyView<'x>: From<&'x T>,

Mutate a borrowed value through the same callback chain. The value and its descendants begin on the non-in-place path.

pub fn mutate_with<T>( &mut self, value: &T, def_region_kind: DefRegionKind, ) -> Result<Any>

where for<'x> AnyView<'x>: From<&'x T>,

Mutate a borrowed value under an explicit definition-region state.

pub fn maybe_inplace_mutate<T: Into<Any>>(&mut self, value: T) -> Result<Any>

Mutate an owned value, allowing an in-place attempt when it remains uniquely owned and no matched callback borrows it.

pub fn maybe_inplace_mutate_with<T: Into<Any>>( &mut self, value: T, def_region_kind: DefRegionKind, ) -> Result<Any>

Mutate an owned value under an explicit definition-region state.

pub fn default_mutate(&mut self) -> Result<Any>

Apply default mutation to the callback’s current value.

This operation always uses the copy path because a callback may still hold a shared borrow of the current value. It may be called repeatedly.

pub fn mutate_result<T>(&mut self, value: &T) -> Result<UnchangedOr<Any>>

where for<'x> AnyView<'x>: From<&'x T>,

Mutate a borrowed child while preserving an unchanged result.

pub fn mutate_with_result<T>( &mut self, value: &T, kind: DefRegionKind, ) -> Result<UnchangedOr<Any>>

where for<'x> AnyView<'x>: From<&'x T>,

Mutate a borrowed child under an explicit region, preserving unchanged.

pub fn default_mutate_result(&mut self) -> Result<UnchangedOr<Any>>

Apply default mutation without materializing an unchanged original.

pub fn var_remap_get(&mut self, var: &MapValue) -> Result<Option<Any>>

Look up an invocation-local identity substitution.

pub fn var_remap_set( &mut self, var: &MapValue, mutated_value: &Any, ) -> Result<()>

Store an invocation-local identity substitution.