Trait datafusion_expr::expr_rewriter::ExprRewriter

pub trait ExprRewriter<E: ExprRewritable = Expr>: Sized {
    fn mutate(&mut self, expr: E) -> Result<E>;

    fn pre_visit(&mut self, _expr: &E) -> Result<RewriteRecursion> { ... }
}

Trait for potentially recursively rewriting an Expr expression tree. When passed to Expr::rewrite, ExpressionVisitor::mutate is invoked recursively on all nodes of an expression tree. See the comments on Expr::rewrite for details on its use

Required Methods

fn mutate(&mut self, expr: E) -> Result<E>

Invoked after all children of expr have been mutated and returns a potentially modified expr.

Provided Methods

fn pre_visit(&mut self, _expr: &E) -> Result<RewriteRecursion>

Invoked before any children of expr are rewritten / visited. Default implementation returns Ok(RewriteRecursion::Continue)

Implementors