Struct mz_transform::analysis::common::DerivedView

pub struct DerivedView<'a> {
    derived: &'a Derived,
    lower: usize,
    upper: usize,
}

The subset of a Derived corresponding to an expression and its children.

Specifically, bounds an interval [lower, upper) that ends with the state of an expression, at upper-1, and is preceded by the state of descendents.

This is best thought of as a node in a tree rather

Fields

derived: &'a Derived

lower: usize

upper: usize

Implementations

impl<'a> DerivedView<'a>

pub fn value<A: Analysis>(&self) -> Option<&'a A::Value>

The value associated with the expression.

pub fn index(&self) -> usize

The post-order traversal index for the expression.

This can be used to index into the full set of results, as provided by an instance of Derived.

pub fn bound<A: Analysis>(&self, id: LocalId) -> Option<&'a A::Value>

The value bound to an identifier, if it has been derived.

There are several reasons the value could not be derived, and this method does not distinguish between them.

pub fn results<A: Analysis>(&self) -> &'a [A::Value]

The results for expression and its children.

The results for the expression itself will be the last element.

Panics

This method panics if A was not installed as a required analysis.

pub fn bindings(&self) -> &'a BTreeMap<LocalId, usize>

Bindings from local identifiers to result offsets for analysis values.

This method returns all bindings, which may include bindings not in scope for the expression and its children; they should be ignored.

pub fn children_rev(&self) -> impl Iterator<Item = DerivedView<'a>> + 'a

Subviews over self corresponding to the children of the expression, in reverse order.

These views should disjointly cover the same interval as self, except for the last element which corresponds to the expression itself.

The number of produced items should exactly match the number of children, which need not be provided as an argument. This relies on the well-formedness of the view, which should exhaust itself just as it enumerates its last (the first) child view.

pub fn last_child(&self) -> DerivedView<'a>

A convenience method for the view over the expressions last child.

This method is appropriate to call on expressions with multiple children, and in particular for Let and LetRecv variants where the body is the last child.

It is an error to call this on a view for an expression with no children.

Trait Implementations

impl<'a> Clone for DerivedView<'a>

fn clone(&self) -> DerivedView<'a>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'a> Copy for DerivedView<'a>