# Function cargo::ops::tree::graph::add_feature

source ·

    fn add_feature(
        graph: &mut Graph<'_>,
        name: InternedString,
        from: Option<usize>,
        to: usize,
        kind: EdgeKind
    ) -> (bool, usize)

Expand description

Adds a feature node between two nodes.

That is, it adds the following:

    from -Edge-> featname -Edge::Feature-> to

Returns a tuple `(missing, index)`. `missing` is true if this feature edge was already added. `index` is the index of the index in the graph of the `Feature` node.