rust/src/test/run-pass/trait-to-str.rs

// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

// xfail-fast

#[no_core];

extern mod core;

use core::{str, int, vec};

trait to_str {
    fn to_str() -> ~str;
}

impl to_str for int {
    fn to_str() -> ~str { int::str(self) }
}

impl<T: to_str> to_str for ~[T] {
    fn to_str() -> ~str {
        ~"[" + str::connect(vec::map(self, |e| e.to_str() ), ~", ") + ~"]"
    }
}

pub fn main() {
    assert 1.to_str() == ~"1";
    assert (~[2, 3, 4]).to_str() == ~"[2, 3, 4]";

    fn indirect<T: to_str>(x: T) -> ~str {
        x.to_str() + ~"!"
    }
    assert indirect(~[10, 20]) == ~"[10, 20]!";

    fn indirect2<T: to_str>(x: T) -> ~str {
        indirect(x)
    }
    assert indirect2(~[1]) == ~"[1]!";
}