Method plan_substring

datafusion/functions/src/unicode/planner.rs:37–44

(
        &self,
        args: Vec<Expr>,
    )

    }

    fn plan_substring(
        &self,
        args: Vec<Expr>,
    ) -> datafusion_common::Result<PlannerResult<Vec<Expr>>> {
        Ok(PlannerResult::Planned(Expr::ScalarFunction(
            ScalarFunction::new_udf(crate::unicode::substr(), args),
        )))
    }
}