Enum mz_transform::attribute::EnvTask

enum EnvTask {
    Bind(Vec<LocalId>, BTreeSet<LocalId>),
    Unbind(BTreeSet<LocalId>),
    Done,
}

Models an environment maintenance task that needs to be executed after visiting a MirRelationExpr. Each task is a state of a finite state machine.

The Env::schedule_tasks hook installs exactly one such task for each subexpression, and the Env::handle_tasks hook removes it.

In addition, the Env::handle_tasks looks at the task installed by the parent expression and modifies it if needed, advancing it through the following states from left to right:

Bind([...,x], {...}) --> Bind([...], {...,x}) --> Unbind({...}) --> Done

Variants

Bind(Vec<LocalId>, BTreeSet<LocalId>)

Extend the environment by binding the last derived attribute under the key given the tail of the lhs Vec and move that key from the lhs Vec to the rhs BTreeSet.

Unbind(BTreeSet<LocalId>)

Remove all LocalId entries in the given set from the environment.

Done

Do not do anything.

Implementations

impl EnvTask

fn bind_one(id: &LocalId) -> Self

Create an EnvTask::Bind state for a single binding.

fn bind_seq(ids: &Vec<LocalId>) -> Self

Create an EnvTask::Bind state for a sequence of bindings.

Trait Implementations

impl Debug for EnvTask

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for EnvTask

fn eq(&self, other: &EnvTask) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for EnvTask

impl StructuralEq for EnvTask

impl StructuralPartialEq for EnvTask