6 releases
0.1.5 | Jul 4, 2019 |
---|---|
0.1.4 | Jul 2, 2019 |
0.1.3 | Jan 3, 2019 |
0.1.2 | Dec 9, 2018 |
#3 in #sweet
25 downloads per month
17KB
369 lines
candy-rs
Syntaxic sugar for Rust: macros for lighter error handling code, and more.
Examples
//! Run with `cargo run --example do_loop -- <number>`
#[macro_use] extern crate candy;
use ::std::*;
type ErrorMsg = borrow::Cow<'static, str>;
fallible! {
fn main ()
-> ()
=>! ErrorMsg
:
let input_number: u64 = {
let (mb_argv_0, mb_argv_1) = {
let mut args = env::args();
(args.next(), args.next())
};
let prog_name = mb_argv_0.unwrap();
match mb_argv_1
.and_then(|argv_1| argv_1.parse().ok())
{
Some(number) => number,
_ => throw!(format!("Usage: {} <number>", prog_name)),
}
};
collatz_conjecture(input_number);
}
fn collatz_conjecture (mut n: u64)
{
do_loop!({
println!("n = {}", n);
if n % 2 == 0 {
n /= 2;
} else {
n = 3 * n + 1;
};
} while n != 1);
println!("Did reach 1.");
}
//! Run with `cargo run --example catch`
#[macro_use] extern crate candy;
use ::std::{
*,
io::Write,
};
fn main ()
{
debug_print_all([0b101010, 0x45].iter())
}
fn debug_print_all (
iterable: impl IntoIterator<Item = impl fmt::Debug>,
)
{
let to_stdout = &mut io::stdout();
// `catch!` allows using the `?` operator. Isn't that nice?
match catch!({
write!(to_stdout, "[")?;
let mut iterator = iterable.into_iter();
let mut count = 0;
if let Some(first) = iterator.next() {
count += 1;
write!(to_stdout, "{:?}", first)?;
while let Some(next) = iterator.next() {
count += 1;
write!(to_stdout, ", {:?}", next)?;
};
};
write!(to_stdout, "]\n")?;
count
} -> usize =>! io::Error)
{
Err(io_err) => {
eprintln!(
"{:?} : could not write to stdout!? Oh well, who cares?",
io_err,
);
},
Ok(n) => {
eprintln!("Successfully wrote {} elements to stdout", n);
},
}
}
Usage
-
Add this line to your
Cargo.toml
(under[dependencies]
):candy = "0.1.5"
-
Add this to your
.rs
code:#[macro_use] extern crate candy;