Hi Philippe,
The following modification of your code compiles. Not sure if it achieves
what you want.
******************************************************************************
******************************************************************************
use std::vec::Vec;
use std::task;
pub enum UINode {
DrawableNode(Container),
ContainerNode(Inside),
}
struct Inside {
layout: fn(&Inside) -> uint,
}
impl Inside {
fn get_id(&self) -> uint {1}
}
trait Trait {}
struct ListInside {
tt: ~Trait: Send,
list: Vec<~UINode>,
}
struct Container {
inside:~ListInside,
}
impl ListInside {
fn match_fn<'a>(&'a self, filter: &'a |&'a UINode| -> Option<&'a
Inside>) ->Option<&'a Inside> {
for inside in self.list.iter() {
match (*filter)(*inside) {
Some(found) => return Some(found),
None => {},
};
}
None
}
fn test_mutable<'a>(&'a mut self, id: uint, update: &'a|component:
&'a mut Inside|) {}
}
fn TestMatchBorrow() {
let task = task::task();
task.spawn (proc() {
let mut viewList: Vec<~Container> = Vec::new();
for ref mut container in viewList.mut_iter() {
/*
//Original code
//let &mut my_var = &mut *(container.inside);
match container.inside.match_fn(&|inside: &UINode| ->
Option<&Inside> {None}) {
Some(inside) =>
container.inside.test_mutable(inside.get_id(), &|component: &mut Inside|
{}),
None => {},
}
*/
//modified code
let mut dotest = false;
fn dummy(arg: &Inside) -> uint {
1
}
let mut ins: Inside = Inside {layout:dummy};
match container.inside.match_fn(&|uinside: &UINode| ->
Option<&Inside> {None}) {
Some(inside) => { dotest = true; ins= *inside;}
None => {},
}
if(dotest == true){
container.inside.test_mutable(ins.get_id(),
&|component: &mut Inside|
{});
}
}
});
}
#[main]
fn main() {
TestMatchBorrow();
}
******************************************************************************
******************************************************************************
On Sun, Apr 27, 2014 at 11:28 AM, Philippe Delrieu <[email protected]
> wrote:
> I try to implement a sort of zoom UI. The UI components are organized in a
> tree. To update a component in the UI I use a search function (match_fn()
> in the example) which take a closure as search criteria and if it returns
> something I use an update function (test_mutable) with a closure to do the
> update part. The update part only need an Id and the closure. So returning
> the found component is not mandatory. If the search function return only a
> copy of the component id it solves the borrow error but I would like to
> have the found component.
>
> I return a reference (Option<&'a Inside>) to avoid object copy. A
> component can have a large sub tree. If I change and return a copy in the
> search function (Option<Inside>) It works. Logic the Inside life time start
> at the Some level (as I understand).
>
> Perhaps you'll have a better idea to do this. I use this pattern (search
> and update function) for this reasons:
> * no multiple owned objects. All object are only owned in the tree.
> * maintain most immutability
>
> I put a new version of the test code nearer to my main code.
>
>
> use std::vec::Vec;
> use std::task;
>
> pub enum UINode {
> DrawableNode(Container),
> ContainerNode(Inside),
> }
>
> struct Inside {
> layout: fn(&Inside) -> uint,
> }
>
> impl Inside {
> fn get_id(&self) -> uint {1}
> }
>
> trait Trait {}
>
> struct ListInside {
> tt: ~Trait: Send,
> list: Vec<~UINode>,
> }
>
> struct Container {
> inside:~ListInside,
> }
>
> impl ListInside {
> fn match_fn<'a>(&'a self, filter: &'a |&'a UINode| -> Option<&'a
> Inside>) ->Option<&'a Inside> {
> for inside in self.list.iter() {
> match (*filter)(*inside) {
> Some(found) => return Some(found),
> None => {},
> };
> }
> None
> }
>
> fn test_mutable<'a>(&'a mut self, id: uint, update: &'a|component: &'a
> mut Inside|) {}
> }
>
> fn TestMatchBorrow() {
> let task = task::task();
> task.spawn (proc() {
>
> let mut viewList: Vec<~Container> = Vec::new();
>
> for ref mut container in viewList.mut_iter() {
> //let &mut my_var = &mut *(container.inside);
> match container.inside.match_fn(&|inside: &UINode| ->
> Option<&Inside> {None}) {
> Some(inside) => container.inside.test_mutable(inside.get_id(),
> &|component: &mut Inside| {}),
> None => {},
> }
> }
> });
>
>
> }
>
> #[main]
> fn main() {
> TestMatchBorrow();
> }
>
> _______________________________________________
> Rust-dev mailing list
> [email protected]
> https://mail.mozilla.org/listinfo/rust-dev
>
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