Trait Patch

pub trait Patch<H: HugrView>: PatchVerification<Node = H::Node> {
    type Outcome;

    const UNCHANGED_ON_FAILURE: bool;

    // Required method
    fn apply(self, h: &mut H) -> Result<Self::Outcome, Self::Error>;
}

A patch that can be applied to a mutable Hugr of type H.

When to use

Use this trait whenever possible in bounds for the most generality. Note that this will require specifying which type H the patch applies to.

When to implement

For patches that work on any H: HugrMut, prefer implementing PatchHugrMut instead. This will automatically implement this trait.

Required Associated Constants

const UNCHANGED_ON_FAILURE: bool

If true, Patch::apply’s of this rewrite guarantee that they do not mutate the Hugr when they return an Err. If false, there is no guarantee; the Hugr should be assumed invalid when Err is returned.

Required Associated Types

type Outcome

The type returned on successful application of the rewrite.

Required Methods

fn apply(self, h: &mut H) -> Result<Self::Outcome, Self::Error>

Mutate the specified Hugr, or fail with an error.

Returns Self::Outcome if successful. If Patch::UNCHANGED_ON_FAILURE is true, then h must be unchanged if Err is returned. See also PatchVerification::verify

Panics

May panic if-and-only-if h would have failed Hugr::validate; that is, implementations may begin with assert!(h.validate()), with debug_assert!(h.validate()) being preferred.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl Patch<PersistentHugr> for PersistentReplacement

const UNCHANGED_ON_FAILURE: bool = true

type Outcome = ()

impl<R: PatchHugrMut, H: HugrMut<Node = R::Node>> Patch<H> for R

const UNCHANGED_ON_FAILURE: bool = R::UNCHANGED_ON_FAILURE

type Outcome = <R as PatchHugrMut>::Outcome