You’re trying to move the ~strs out of the vector. You’ll need to use
`move_iter`:
~~~
let ports = do myvect.move_iter().map |s| {
let (pport, cchan) = stream();
do spawn {
cchan.send(fun(s))
}
pport
}.to_owned_vec();
~~~
Also note the use of `to_owned_vec`. `map` lazily returns a `Map` iterator -
you need to explicitly drain it.
(Note I haven’t tried compiling this)
~Brendan
On 3 Nov 2013, at 7:04 am, Leah Hanson <astriea...@gmail.com> wrote:
> Thanks, Scott, I think that's closer.
>
> However, now I'm having trouble with my pointer types. Using the element
> inside a spawn means that I need to capture the owned string in the right way
> so that the compiler allows me to give it to the other task.
>
> This version:
> ~~~
> let ports = do myvect.iter().map |s| {
> let (pport, cchan) = stream();
> do spawn {
> cchan.send(fun(*s))
> }
> pport
> };
> ~~~
> gives me pointer-type related errors:
> • error: cannot move out of dereference of & pointer
> • cchan.send(fun(*s))
> • error: cannot borrow immutable local variable as mutable
> • when I iterate over the Ports later
> • error: cannot capture variable of type `&~str`, which does not
> fulfill `Send`, in a bounded closure
> • cchan.send(fun(*s))
> I also tried a version with |&s| and cchan.send(fun(s)), which gave me
> different errors:
> • error: cannot move out of captured outer variable in a heap closure
> • cchan.send(fun(*s))
> • error: cannot move out of dereference of & pointer
> • on the |&s|
> • error: cannot borrow immutable local variable as mutable
> • when I iterate over the Ports later
>
> I'm very new to Rust. What do I need to do to let the compiler know that I'm
> not going to use anything in the first vec anymore? That I just want the ~str
> pointers directly?
>
> (I put the |s| outside the {} because putting it inside seemed to confuse
> things -- in that case, rustc expected an identifier instead of the `let`
> that comes next, so I assumed that `do v.iter().map {|s| ...}` is a syntax
> error.)
>
> Thanks,
> Leah
>
>
>
>
> On Sat, Nov 2, 2013 at 3:23 PM, Scott Lawrence <byt...@gmail.com> wrote:
> I would think:
>
> let ports = do myvect.iter().map { |e| something(e) }
>
>
> On Sat, 2 Nov 2013, Leah Hanson wrote:
>
> Hi,
>
> I have a ~[~str]. I have code that will turn a ~str into a Port<uint>.
>
> I want to end up with a [Port<uint>]. (or ~ or @ or whatever. I just want
> to be able to iterate over the Ports later.)
>
> Since I'm not sure what looping construct to use, I tried with a for-each
> loop.
>
> ~~~
> let ports = for s in myvect.iter() {
> let (pport, cchan) = stream();
> do spawn {
> cchan.send(fun(*s))
> }
> pport
> };
> ~~~
>
> As you might, expect I got an error:
> error: mismatched types: expected `()` but found `std::comm::Port<uint>`
> (expected () but found struct std::comm::Port)
>
> From this, I take it that for loops must return `()`, rather than an actual
> value. When I searched for a map function in the documentation, I only
> found a Map type.
>
> How would you map one vector to a vector of a different element type?
>
> Thanks,
> Leah
>
>
> --
> Scott Lawrence
>
> _______________________________________________
> Rust-dev mailing list
> Rust-dev@mozilla.org
> https://mail.mozilla.org/listinfo/rust-dev
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