关于rust：FromStr和FromErr解析字符串时遇到麻烦

Trouble with FromStr & FromErr to parse a string

我正在尝试编写一个简单的Rust函数来解析字符串并创建结构。我正在使用Result作为解析结果。我希望它可用于许多数字类型(整数和浮点数)。我使用的方法与Rust结果文档中使用的方法相同，并且我的错误类型是一条简单的错误消息(&str)

这是我的源代码：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29

#![feature(plugin)]
#![plugin(regex_macros)]
extern crate regex;

use std::str::FromStr;
use regex::Regex;

struct Point< T > {
x: T,
y: T
}

fn parse_string<T: FromStr>(input: &str) -> Result<Point< T >, &'static str> {
let input = input.trim();
if input.len() == 0 {
return Err("Empty string");
}
let re = regex!(r"point2d\\{ *x=(.*)+, *y=(.*)+ *\\}");
let mresult = try!(re.captures(input).ok_or("Could not match regex"));
let x_str = try!(mresult.at(1).ok_or("Couldn't find X"));
let y_str = try!(mresult.at(2).ok_or("Couldn't find Y"));
let x: T = try!(T::from_str(x_str));
let y: T = try!(T::from_str(y_str));
Ok(Point{ x: x, y: y });
}

fn main() {
let point: Point<i64> = parse_string("point2d{x=10, y=20}").unwrap();
}

和编译器错误：

1
2
3
4
5
6
7
8
9
10
11
12
13

Compiling fromerrtest v0.0.1 (file:///XXXXXX)
<std macros>:6:1: 6:41 error: the trait `core::error::FromError<<T as core::str::FromStr>::Err>` is not implemented for the type `&str` [E0277]
<std macros>:6 $ crate:: error:: FromError:: from_error ( err ) ) } } )
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<std macros>:1:1: 6:57 note: in expansion of try!
src/main.rs:22:16: 22:41 note: expansion site
<std macros>:6:1: 6:41 error: the trait `core::error::FromError<<T as core::str::FromStr>::Err>` is not implemented for the type `&str` [E0277]
<std macros>:6 $ crate:: error:: FromError:: from_error ( err ) ) } } )
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<std macros>:1:1: 6:57 note: in expansion of try!
src/main.rs:23:16: 23:41 note: expansion site
error: aborting due to 2 previous errors
Could not compile `fromerrtest`.

我已经阅读了Armin Ronacher对FromErr的解释，但是我不确定要实现此功能必须实现什么。

这是Beta之前的最后一分钟更改。 FromError不见了，您现在应该使用常规的From类型：http://doc.rust-lang.org/nightly/std/convert/trait.From.html