diff options
Diffstat (limited to 'src/doc/book/listings/ch15-smart-pointers/listing-15-25')
3 files changed, 32 insertions, 0 deletions
diff --git a/src/doc/book/listings/ch15-smart-pointers/listing-15-25/Cargo.lock b/src/doc/book/listings/ch15-smart-pointers/listing-15-25/Cargo.lock new file mode 100644 index 000000000..a792c49aa --- /dev/null +++ b/src/doc/book/listings/ch15-smart-pointers/listing-15-25/Cargo.lock @@ -0,0 +1,6 @@ +# This file is automatically @generated by Cargo. +# It is not intended for manual editing. +[[package]] +name = "cons-list" +version = "0.1.0" + diff --git a/src/doc/book/listings/ch15-smart-pointers/listing-15-25/Cargo.toml b/src/doc/book/listings/ch15-smart-pointers/listing-15-25/Cargo.toml new file mode 100644 index 000000000..dce1515c3 --- /dev/null +++ b/src/doc/book/listings/ch15-smart-pointers/listing-15-25/Cargo.toml @@ -0,0 +1,6 @@ +[package] +name = "cons-list" +version = "0.1.0" +edition = "2021" + +[dependencies] diff --git a/src/doc/book/listings/ch15-smart-pointers/listing-15-25/src/main.rs b/src/doc/book/listings/ch15-smart-pointers/listing-15-25/src/main.rs new file mode 100644 index 000000000..f36c7fd06 --- /dev/null +++ b/src/doc/book/listings/ch15-smart-pointers/listing-15-25/src/main.rs @@ -0,0 +1,20 @@ +use crate::List::{Cons, Nil}; +use std::cell::RefCell; +use std::rc::Rc; + +#[derive(Debug)] +enum List { + Cons(i32, RefCell<Rc<List>>), + Nil, +} + +impl List { + fn tail(&self) -> Option<&RefCell<Rc<List>>> { + match self { + Cons(_, item) => Some(item), + Nil => None, + } + } +} + +fn main() {} |