Hi, Christophe,
Won't wrapping the first `for` loop into curly braces help? I suspect
this happens because of `for` loop desugaring, which kind of "leaves"
the iterator created by `execute_query()` "in scope" (not really, but
only for borrow checker).
2014-05-29 19:38 GMT+04:00 Christophe Pedretti <christophe.pedre...@gmail.com>:
> Hello all,
>
> i know that this issue is already covered by issues #9113 #6393 and #9113
> but actually i have no solution. My code is a library for accessing
> databases. In my example, the database represented by db containes a table t
> with columns i:integer, f:float, t:text, b:blob.
>
> Everything works fine except the following code used to test my library
>
> match db.prepare_statement("SELECT i,f,t,b FROM t where t like ?;") {
>
> Ok(mut st) => {
>
> st.set_string(1, "%o%");
>
> for i in st.execute_query() {
>
> match i {
>
> Ok(s) => println!("{}:{}:{}:{}", s.get_long(0), s.get_double(1),
> s.get_string(2), s.get_blob(3) ),
>
> Err(e) => match e.detail {
>
> Some(s) => println!("{}", s),
>
> None => ()
>
> }
>
> }
>
> }
>
> st.set_string(1, "%e%"); <- PROBLEM HERE
> for i in st.execute_query() { <- PROBLEM HERE
>
> ...
> }
>
> },
> Err(e) => match e.detail {
>
> None => (),
>
> Some(s) => println!("{}", s)
>
> }
>
> }
>
> The compilation error says
>
> test-db.rs:71:8: 71:10 error: cannot borrow `st` as mutable more than once
> at a time
> test-db.rs:71
> st.set_string(1, "%e%");
> ^~
> test-db.rs:61:17: 61:19 note: previous borrow of `st` occurs here; the
> mutable borrow prevents subse
> quent moves, borrows, or modification of `st` until the borrow ends
> test-db.rs:61 for i in
> st.execute_query() {
> ^~
> test-db.rs:88:7: 88:7 note: previous borrow ends here
> test-db.rs:58 match
> db.prepare_statement("SELECT i,f,t,b FROM t wh
> ere t like ?;") {
> ...
> test-db.rs:88 }
> ^
> error: aborting due to previous error
>
> do we have a solution for #6393 ?
>
> Thanks
>
> --
> Christophe
> http://chris-pe.github.io/Rustic/
>
>
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