{"ast_node_type":"function","tokens":[{"end":68,"kind":"keyword","start":0,"text":"//!"}]}
//!     fn source(&self, e: &Ed<'a>) -> Nd<'a> { let &(s,_) = e; s }
//!     }
//!     fn target(&self, e: &Ed<'a>) -> Nd<'a> { let &(_,t) = e; t }