diff options
Diffstat (limited to 'src/doc/book/listings/ch15-smart-pointers/listing-15-28')
3 files changed, 45 insertions, 0 deletions
diff --git a/src/doc/book/listings/ch15-smart-pointers/listing-15-28/Cargo.lock b/src/doc/book/listings/ch15-smart-pointers/listing-15-28/Cargo.lock new file mode 100644 index 000000000..dd1f00a87 --- /dev/null +++ b/src/doc/book/listings/ch15-smart-pointers/listing-15-28/Cargo.lock @@ -0,0 +1,6 @@ +# This file is automatically @generated by Cargo. +# It is not intended for manual editing. +[[package]] +name = "tree" +version = "0.1.0" + diff --git a/src/doc/book/listings/ch15-smart-pointers/listing-15-28/Cargo.toml b/src/doc/book/listings/ch15-smart-pointers/listing-15-28/Cargo.toml new file mode 100644 index 000000000..0bbf897d0 --- /dev/null +++ b/src/doc/book/listings/ch15-smart-pointers/listing-15-28/Cargo.toml @@ -0,0 +1,6 @@ +[package] +name = "tree" +version = "0.1.0" +edition = "2021" + +[dependencies] diff --git a/src/doc/book/listings/ch15-smart-pointers/listing-15-28/src/main.rs b/src/doc/book/listings/ch15-smart-pointers/listing-15-28/src/main.rs new file mode 100644 index 000000000..fabd1cbce --- /dev/null +++ b/src/doc/book/listings/ch15-smart-pointers/listing-15-28/src/main.rs @@ -0,0 +1,33 @@ +// ANCHOR: here +use std::cell::RefCell; +use std::rc::{Rc, Weak}; + +#[derive(Debug)] +struct Node { + value: i32, + parent: RefCell<Weak<Node>>, + children: RefCell<Vec<Rc<Node>>>, +} +// ANCHOR_END: here + +// ANCHOR: there +fn main() { + let leaf = Rc::new(Node { + value: 3, + parent: RefCell::new(Weak::new()), + children: RefCell::new(vec![]), + }); + + println!("leaf parent = {:?}", leaf.parent.borrow().upgrade()); + + let branch = Rc::new(Node { + value: 5, + parent: RefCell::new(Weak::new()), + children: RefCell::new(vec![Rc::clone(&leaf)]), + }); + + *leaf.parent.borrow_mut() = Rc::downgrade(&branch); + + println!("leaf parent = {:?}", leaf.parent.borrow().upgrade()); +} +// ANCHOR_END: there |