Function find_exprs_in_expr

datafusion/expr/src/utils.rs:695–714

Search an `Expr`, and all of its nested `Expr`'s, for any that pass the provided test. The returned `Expr`'s are deduplicated and returned in order of appearance (depth first).

(expr: &Expr, test_fn: &F)

/// provided test. The returned `Expr`'s are deduplicated and returned in order
/// of appearance (depth first).
fn find_exprs_in_expr<F>(expr: &Expr, test_fn: &F) -> Vec<Expr>
where
    F: Fn(&Expr) -> bool,
{
    let mut exprs = vec![];
    expr.apply(|expr| {
        if test_fn(expr) {
            if !(exprs.contains(expr)) {
                exprs.push(expr.clone())
            }
            // Stop recursing down this expr once we find a match
            return Ok(TreeNodeRecursion::Jump);
        }

        Ok(TreeNodeRecursion::Continue)
    })
    // pre_visit always returns OK, so this will always too
    .expect("no way to return error during recursion");
    exprs
}

/// Recursively inspect an [`Expr`] and all its children.
pub fn inspect_expr_pre<F, E>(expr: &Expr, mut f: F) -> Result<(), E>