4 releases
0.1.3 | Aug 13, 2024 |
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0.1.2 | Aug 13, 2024 |
0.1.1 | Aug 12, 2024 |
0.1.0 | Aug 12, 2024 |
#29 in #self-referential
Used in incrstruct
17KB
322 lines
Incremental Structure
A Rust crate for building self-referencing structs using two-phase initialization.
Example
use std::cell::{Ref, RefCell};
use incrstruct::IncrStruct;
#[derive(IncrStruct)]
struct AStruct<'a> {
#[borrows(b)] // Borrowing from a tail field
c: &'a Ref<'a, i32>, // is possible.
#[borrows(a)] // You can only borrow from fields that
b: Ref<'a, i32>, // come after the current field.
a: RefCell<i32>, // A head field. Since you can only borrow
// immutable references, RefCell is useful.
#[header] // The required header field.
hdr: incrstruct::Header, // The name is arbitrary.
}
// The AStructInit trait is generated by the derive macro and
// ensures the contract between the incrstruct library code and
// the user provided code matches. The functions are invoked in
// reverse field declaration order.
impl<'a> AStructInit<'a> for AStruct<'a> {
fn init_field_c(b: &'a Ref<'a, i32>) -> &'a Ref<'a, i32> {
b
}
fn init_field_b(a: &'a RefCell<i32>) -> Ref<'a, i32> {
a.borrow()
}
}
// Only head fields are provided to the generated `new_X` functions.
let my_a = AStruct::new_box(RefCell::new(42));
assert_eq!(*my_a.a.borrow(), *my_a.b);
See the documentation for more information.
Dependencies
~220–660KB
~16K SLoC