{"ast_node_type":"variable","tokens":[{"end":51,"kind":"keyword","start":0,"text":"//!"}]}
//!     let nodes = vec!["{x,y}","{x}","{y}","{}"];
//! pub fn render_to<W: Write>(output: &mut W) {
//!     let edges = vec![(0,1), (0,2), (1,3), (2,3)];