rust/src/libstd/macros.rs
Alex Crichton 76c313ceb1 Lift $dst outside the closure in write!
If you were writing to something along the lines of `self.foo` then with the new
closure rules it meant that you were borrowing `self` for the entirety of the
closure, meaning that you couldn't format other fields of `self` at the same
time as writing to a buffer contained in `self`.

By lifting the borrow outside of the closure the borrow checker can better
understand that you're only borrowing one of the fields at a time. This had to
use type ascription as well in order to preserve trait object coercions.
2014-02-13 13:05:48 -08:00

186 lines
4.8 KiB
Rust

// Copyright 2014 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.
#[macro_escape];
#[macro_export]
macro_rules! log(
($lvl:expr, $($arg:tt)+) => ({
let lvl = $lvl;
if lvl <= __log_level() {
format_args!(|args| {
::std::logging::log(lvl, args)
}, $($arg)+)
}
})
)
#[macro_export]
macro_rules! error(
($($arg:tt)*) => (log!(1u32, $($arg)*))
)
#[macro_export]
macro_rules! warn(
($($arg:tt)*) => (log!(2u32, $($arg)*))
)
#[macro_export]
macro_rules! info(
($($arg:tt)*) => (log!(3u32, $($arg)*))
)
#[macro_export]
macro_rules! debug(
($($arg:tt)*) => (if cfg!(not(ndebug)) { log!(4u32, $($arg)*) })
)
#[macro_export]
macro_rules! log_enabled(
($lvl:expr) => ({
let lvl = $lvl;
lvl <= __log_level() && (lvl != 4 || cfg!(not(ndebug)))
})
)
#[macro_export]
macro_rules! fail(
() => (
fail!("explicit failure")
);
($msg:expr) => (
::std::rt::begin_unwind($msg, file!(), line!())
);
($fmt:expr, $($arg:tt)*) => ({
// a closure can't have return type !, so we need a full
// function to pass to format_args!, *and* we need the
// file and line numbers right here; so an inner bare fn
// is our only choice.
#[inline]
fn run_fmt(fmt: &::std::fmt::Arguments) -> ! {
::std::rt::begin_unwind_fmt(fmt, file!(), line!())
}
format_args!(run_fmt, $fmt, $($arg)*)
});
)
#[macro_export]
macro_rules! assert(
($cond:expr) => (
if !$cond {
fail!("assertion failed: {:s}", stringify!($cond))
}
);
($cond:expr, $msg:expr) => (
if !$cond {
fail!($msg)
}
);
($cond:expr, $($arg:expr),+) => (
if !$cond {
fail!($($arg),+)
}
);
)
#[macro_export]
macro_rules! assert_eq(
($given:expr , $expected:expr) => ({
let given_val = &($given);
let expected_val = &($expected);
// check both directions of equality....
if !((*given_val == *expected_val) &&
(*expected_val == *given_val)) {
fail!("assertion failed: `(left == right) && (right == left)` \
(left: `{:?}`, right: `{:?}`)", *given_val, *expected_val)
}
})
)
/// A utility macro for indicating unreachable code. It will fail if
/// executed. This is occasionally useful to put after loops that never
/// terminate normally, but instead directly return from a function.
///
/// # Example
///
/// ~~~rust
/// fn choose_weighted_item(v: &[Item]) -> Item {
/// assert!(!v.is_empty());
/// let mut so_far = 0u;
/// for item in v.iter() {
/// so_far += item.weight;
/// if so_far > 100 {
/// return item;
/// }
/// }
/// // The above loop always returns, so we must hint to the
/// // type checker that it isn't possible to get down here
/// unreachable!();
/// }
/// ~~~
#[macro_export]
macro_rules! unreachable(
() => (fail!("internal error: entered unreachable code"))
)
/// A standardised placeholder for marking unfinished code. It fails with the
/// message `"not yet implemented"` when executed.
#[macro_export]
macro_rules! unimplemented(
() => (fail!("not yet implemented"))
)
#[macro_export]
macro_rules! format(
($($arg:tt)*) => (
format_args!(::std::fmt::format, $($arg)*)
)
)
#[macro_export]
macro_rules! write(
($dst:expr, $($arg:tt)*) => ({
let dst: &mut ::std::io::Writer = $dst;
format_args!(|args| { ::std::fmt::write(dst, args) }, $($arg)*)
})
)
#[macro_export]
macro_rules! writeln(
($dst:expr, $($arg:tt)*) => ({
let dst: &mut ::std::io::Writer = $dst;
format_args!(|args| { ::std::fmt::writeln(dst, args) }, $($arg)*)
})
)
#[macro_export]
macro_rules! print(
($($arg:tt)*) => (format_args!(::std::io::stdio::print_args, $($arg)*))
)
#[macro_export]
macro_rules! println(
($($arg:tt)*) => (format_args!(::std::io::stdio::println_args, $($arg)*))
)
#[macro_export]
macro_rules! local_data_key(
($name:ident: $ty:ty) => (
static $name: ::std::local_data::Key<$ty> = &::std::local_data::Key;
);
(pub $name:ident: $ty:ty) => (
pub static $name: ::std::local_data::Key<$ty> = &::std::local_data::Key;
);
)
#[macro_export]
macro_rules! if_ok(
($e:expr) => (match $e { Ok(e) => e, Err(e) => return Err(e) })
)