rust/tests/ui/try-operator.rs

193 lines
3.5 KiB
Rust

//@ run-pass
#![allow(dead_code)]
use std::fs::File;
use std::io::{Read, self};
use std::num::ParseIntError;
use std::str::FromStr;
fn on_method() -> Result<i32, ParseIntError> {
Ok("1".parse::<i32>()? + "2".parse::<i32>()?)
}
fn in_chain() -> Result<String, ParseIntError> {
Ok("3".parse::<i32>()?.to_string())
}
fn on_call() -> Result<i32, ParseIntError> {
fn parse<T: FromStr>(s: &str) -> Result<T, T::Err> {
s.parse()
}
Ok(parse("4")?)
}
fn nested() -> Result<i32, ParseIntError> {
Ok("5".parse::<i32>()?.to_string().parse()?)
}
fn on_path() -> Result<i32, ParseIntError> {
let x = "6".parse::<i32>();
Ok(x?)
}
fn on_macro() -> Result<i32, ParseIntError> {
macro_rules! id {
($e:expr) => { $e }
}
Ok(id!("7".parse::<i32>())?)
}
fn on_parens() -> Result<i32, ParseIntError> {
let x = "8".parse::<i32>();
Ok((x)?)
}
fn on_block() -> Result<i32, ParseIntError> {
let x = "9".parse::<i32>();
Ok({x}?)
}
fn on_field() -> Result<i32, ParseIntError> {
struct Pair<A, B> { a: A, b: B }
let x = Pair { a: "10".parse::<i32>(), b: 0 };
Ok(x.a?)
}
fn on_tuple_field() -> Result<i32, ParseIntError> {
let x = ("11".parse::<i32>(), 0);
Ok(x.0?)
}
fn on_try() -> Result<i32, ParseIntError> {
let x = "12".parse::<i32>().map(|i| i.to_string().parse::<i32>());
Ok(x??)
}
fn on_binary_op() -> Result<i32, ParseIntError> {
let x = 13 - "14".parse::<i32>()?;
let y = "15".parse::<i32>()? - 16;
let z = "17".parse::<i32>()? - "18".parse::<i32>()?;
Ok(x + y + z)
}
fn on_index() -> Result<i32, ParseIntError> {
let x = [19];
let y = "0".parse::<usize>();
Ok(x[y?])
}
fn on_args() -> Result<i32, ParseIntError> {
fn sub(x: i32, y: i32) -> i32 { x - y }
let x = "20".parse();
let y = "21".parse();
Ok(sub(x?, y?))
}
fn on_if() -> Result<i32, ParseIntError> {
Ok(if true {
"22".parse::<i32>()
} else {
"23".parse::<i32>()
}?)
}
fn on_if_let() -> Result<i32, ParseIntError> {
Ok(if let Ok(..) = "24".parse::<i32>() {
"25".parse::<i32>()
} else {
"26".parse::<i32>()
}?)
}
fn on_match() -> Result<i32, ParseIntError> {
Ok(match "27".parse::<i32>() {
Err(..) => "28".parse::<i32>(),
Ok(..) => "29".parse::<i32>(),
}?)
}
fn tight_binding() -> Result<bool, ()> {
fn ok<T>(x: T) -> Result<T, ()> { Ok(x) }
let x = ok(true);
Ok(!x?)
}
// just type check
fn merge_error() -> Result<i32, Error> {
let mut s = String::new();
File::open("foo.txt")?.read_to_string(&mut s)?;
Ok(s.parse::<i32>()? + 1)
}
fn main() {
assert_eq!(Ok(3), on_method());
assert_eq!(Ok("3".to_string()), in_chain());
assert_eq!(Ok(4), on_call());
assert_eq!(Ok(5), nested());
assert_eq!(Ok(6), on_path());
assert_eq!(Ok(7), on_macro());
assert_eq!(Ok(8), on_parens());
assert_eq!(Ok(9), on_block());
assert_eq!(Ok(10), on_field());
assert_eq!(Ok(11), on_tuple_field());
assert_eq!(Ok(12), on_try());
assert_eq!(Ok(-3), on_binary_op());
assert_eq!(Ok(19), on_index());
assert_eq!(Ok(-1), on_args());
assert_eq!(Ok(22), on_if());
assert_eq!(Ok(25), on_if_let());
assert_eq!(Ok(29), on_match());
assert_eq!(Ok(false), tight_binding());
}
enum Error {
Io(io::Error),
Parse(ParseIntError),
}
impl From<io::Error> for Error {
fn from(e: io::Error) -> Error {
Error::Io(e)
}
}
impl From<ParseIntError> for Error {
fn from(e: ParseIntError) -> Error {
Error::Parse(e)
}
}