Method children_mut

src/expr/src/relation.rs:2287–2329

Iterates through mutable references to child expressions.

(&mut self)

    /// Iterates through mutable references to child expressions.
    pub fn children_mut(&mut self) -> impl DoubleEndedIterator<Item = &mut Self> {
        let mut first = None;
        let mut second = None;
        let mut rest = None;
        let mut last = None;

        use MirRelationExpr::*;
        match self {
            Constant { .. } | Get { .. } => (),
            Let { value, body, .. } => {
                first = Some(&mut **value);
                second = Some(&mut **body);
            }
            LetRec { values, body, .. } => {
                rest = Some(values);
                last = Some(&mut **body);
            }
            Project { input, .. }
            | Map { input, .. }
            | FlatMap { input, .. }
            | Filter { input, .. }
            | Reduce { input, .. }
            | TopK { input, .. }
            | Negate { input }
            | Threshold { input }
            | ArrangeBy { input, .. } => {
                first = Some(&mut **input);
            }
            Join { inputs, .. } => {
                rest = Some(inputs);
            }
            Union { base, inputs } => {
                first = Some(&mut **base);
                rest = Some(inputs);
            }
        }

        first
            .into_iter()
            .chain(second)
            .chain(rest.into_iter().flatten())
            .chain(last)
    }

    /// Iterative pre-order visitor.
    pub fn visit_pre<'a, F: FnMut(&'a Self)>(&'a self, mut f: F) {