Method visit

prqlc/prqlc/src/utils/toposort.rs:60–80

(&mut self, dag: &Dag, n: usize)

impl Toposort {
    fn visit(&mut self, dag: &Dag, n: usize) -> Result<(), ()> {
        let node = self.nodes.get_mut(n).unwrap();
        if node.done {
            return Ok(());
        }
        if node.visiting {
            return Err(());
        }
        node.visiting = true;

        for m in &dag[n] {
            self.visit(dag, *m)?;
        }

        let node = self.nodes.get_mut(n).unwrap();
        node.visiting = false;
        node.done = true;
        self.order.push(n);

        Ok(())
    }
}

#[cfg(test)]