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Diffstat (limited to 'ctr-std/src/macros.rs')
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diff --git a/ctr-std/src/macros.rs b/ctr-std/src/macros.rs new file mode 100644 index 0000000..0ce6b0a --- /dev/null +++ b/ctr-std/src/macros.rs @@ -0,0 +1,481 @@ +// 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. + +//! Standard library macros +//! +//! This modules contains a set of macros which are exported from the standard +//! library. Each macro is available for use when linking against the standard +//! library. + +/// The entry point for panic of Rust threads. +/// +/// This macro is used to inject panic into a Rust thread, causing the thread to +/// panic entirely. Each thread's panic can be reaped as the `Box<Any>` type, +/// and the single-argument form of the `panic!` macro will be the value which +/// is transmitted. +/// +/// The multi-argument form of this macro panics with a string and has the +/// `format!` syntax for building a string. +/// +/// # Examples +/// +/// ```should_panic +/// # #![allow(unreachable_code)] +/// panic!(); +/// panic!("this is a terrible mistake!"); +/// panic!(4); // panic with the value of 4 to be collected elsewhere +/// panic!("this is a {} {message}", "fancy", message = "message"); +/// ``` +#[macro_export] +#[stable(feature = "rust1", since = "1.0.0")] +#[allow_internal_unstable] +macro_rules! panic { + () => ({ + panic!("explicit panic") + }); + ($msg:expr) => ({ + $crate::rt::begin_panic($msg, { + // static requires less code at runtime, more constant data + static _FILE_LINE: (&'static str, u32) = (file!(), line!()); + &_FILE_LINE + }) + }); + ($fmt:expr, $($arg:tt)+) => ({ + $crate::rt::begin_panic_fmt(&format_args!($fmt, $($arg)+), { + // The leading _'s are to avoid dead code warnings if this is + // used inside a dead function. Just `#[allow(dead_code)]` is + // insufficient, since the user may have + // `#[forbid(dead_code)]` and which cannot be overridden. + static _FILE_LINE: (&'static str, u32) = (file!(), line!()); + &_FILE_LINE + }) + }); +} + +/// Macro for printing to the standard output. +/// +/// Equivalent to the `println!` macro except that a newline is not printed at +/// the end of the message. +/// +/// Note that stdout is frequently line-buffered by default so it may be +/// necessary to use `io::stdout().flush()` to ensure the output is emitted +/// immediately. +/// +/// # Panics +/// +/// Panics if writing to `io::stdout()` fails. +/// +/// # Examples +/// +/// ``` +/// use std::io::{self, Write}; +/// +/// print!("this "); +/// print!("will "); +/// print!("be "); +/// print!("on "); +/// print!("the "); +/// print!("same "); +/// print!("line "); +/// +/// io::stdout().flush().unwrap(); +/// +/// print!("this string has a newline, why not choose println! instead?\n"); +/// +/// io::stdout().flush().unwrap(); +/// ``` +#[macro_export] +#[stable(feature = "rust1", since = "1.0.0")] +#[allow_internal_unstable] +macro_rules! print { + ($($arg:tt)*) => ($crate::io::_print(format_args!($($arg)*))); +} + +/// Macro for printing to the standard output, with a newline. On all +/// platforms, the newline is the LINE FEED character (`\n`/`U+000A`) alone +/// (no additional CARRIAGE RETURN (`\r`/`U+000D`). +/// +/// Use the `format!` syntax to write data to the standard output. +/// See `std::fmt` for more information. +/// +/// # Panics +/// +/// Panics if writing to `io::stdout()` fails. +/// +/// # Examples +/// +/// ``` +/// println!(); +/// println!("hello there!"); +/// println!("format {} arguments", "some"); +/// ``` +#[macro_export] +#[stable(feature = "rust1", since = "1.0.0")] +macro_rules! println { + () => (print!("\n")); + ($fmt:expr) => (print!(concat!($fmt, "\n"))); + ($fmt:expr, $($arg:tt)*) => (print!(concat!($fmt, "\n"), $($arg)*)); +} + +/// A macro to select an event from a number of receivers. +/// +/// This macro is used to wait for the first event to occur on a number of +/// receivers. It places no restrictions on the types of receivers given to +/// this macro, this can be viewed as a heterogeneous select. +/// +/// # Examples +/// +/// ``` +/// #![feature(mpsc_select)] +/// +/// use std::thread; +/// use std::sync::mpsc; +/// +/// // two placeholder functions for now +/// fn long_running_thread() {} +/// fn calculate_the_answer() -> u32 { 42 } +/// +/// let (tx1, rx1) = mpsc::channel(); +/// let (tx2, rx2) = mpsc::channel(); +/// +/// thread::spawn(move|| { long_running_thread(); tx1.send(()).unwrap(); }); +/// thread::spawn(move|| { tx2.send(calculate_the_answer()).unwrap(); }); +/// +/// select! { +/// _ = rx1.recv() => println!("the long running thread finished first"), +/// answer = rx2.recv() => { +/// println!("the answer was: {}", answer.unwrap()); +/// } +/// } +/// # drop(rx1.recv()); +/// # drop(rx2.recv()); +/// ``` +/// +/// For more information about select, see the `std::sync::mpsc::Select` structure. +#[macro_export] +#[unstable(feature = "mpsc_select", issue = "27800")] +macro_rules! select { + ( + $($name:pat = $rx:ident.$meth:ident() => $code:expr),+ + ) => ({ + use $crate::sync::mpsc::Select; + let sel = Select::new(); + $( let mut $rx = sel.handle(&$rx); )+ + unsafe { + $( $rx.add(); )+ + } + let ret = sel.wait(); + $( if ret == $rx.id() { let $name = $rx.$meth(); $code } else )+ + { unreachable!() } + }) +} + +#[cfg(test)] +macro_rules! assert_approx_eq { + ($a:expr, $b:expr) => ({ + let (a, b) = (&$a, &$b); + assert!((*a - *b).abs() < 1.0e-6, + "{} is not approximately equal to {}", *a, *b); + }) +} + +/// Built-in macros to the compiler itself. +/// +/// These macros do not have any corresponding definition with a `macro_rules!` +/// macro, but are documented here. Their implementations can be found hardcoded +/// into libsyntax itself. +#[cfg(dox)] +pub mod builtin { + /// The core macro for formatted string creation & output. + /// + /// This macro produces a value of type [`fmt::Arguments`]. This value can be + /// passed to the functions in [`std::fmt`] for performing useful functions. + /// All other formatting macros ([`format!`], [`write!`], [`println!`], etc) are + /// proxied through this one. + /// + /// For more information, see the documentation in [`std::fmt`]. + /// + /// [`fmt::Arguments`]: ../std/fmt/struct.Arguments.html + /// [`std::fmt`]: ../std/fmt/index.html + /// [`format!`]: ../std/macro.format.html + /// [`write!`]: ../std/macro.write.html + /// [`println!`]: ../std/macro.println.html + /// + /// # Examples + /// + /// ``` + /// use std::fmt; + /// + /// let s = fmt::format(format_args!("hello {}", "world")); + /// assert_eq!(s, format!("hello {}", "world")); + /// + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[macro_export] + macro_rules! format_args { ($fmt:expr, $($args:tt)*) => ({ + /* compiler built-in */ + }) } + + /// Inspect an environment variable at compile time. + /// + /// This macro will expand to the value of the named environment variable at + /// compile time, yielding an expression of type `&'static str`. + /// + /// If the environment variable is not defined, then a compilation error + /// will be emitted. To not emit a compile error, use the `option_env!` + /// macro instead. + /// + /// # Examples + /// + /// ``` + /// let path: &'static str = env!("PATH"); + /// println!("the $PATH variable at the time of compiling was: {}", path); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[macro_export] + macro_rules! env { ($name:expr) => ({ /* compiler built-in */ }) } + + /// Optionally inspect an environment variable at compile time. + /// + /// If the named environment variable is present at compile time, this will + /// expand into an expression of type `Option<&'static str>` whose value is + /// `Some` of the value of the environment variable. If the environment + /// variable is not present, then this will expand to `None`. + /// + /// A compile time error is never emitted when using this macro regardless + /// of whether the environment variable is present or not. + /// + /// # Examples + /// + /// ``` + /// let key: Option<&'static str> = option_env!("SECRET_KEY"); + /// println!("the secret key might be: {:?}", key); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[macro_export] + macro_rules! option_env { ($name:expr) => ({ /* compiler built-in */ }) } + + /// Concatenate identifiers into one identifier. + /// + /// This macro takes any number of comma-separated identifiers, and + /// concatenates them all into one, yielding an expression which is a new + /// identifier. Note that hygiene makes it such that this macro cannot + /// capture local variables. Also, as a general rule, macros are only + /// allowed in item, statement or expression position. That means while + /// you may use this macro for referring to existing variables, functions or + /// modules etc, you cannot define a new one with it. + /// + /// # Examples + /// + /// ``` + /// #![feature(concat_idents)] + /// + /// # fn main() { + /// fn foobar() -> u32 { 23 } + /// + /// let f = concat_idents!(foo, bar); + /// println!("{}", f()); + /// + /// // fn concat_idents!(new, fun, name) { } // not usable in this way! + /// # } + /// ``` + #[unstable(feature = "concat_idents_macro", issue = "29599")] + #[macro_export] + macro_rules! concat_idents { + ($($e:ident),*) => ({ /* compiler built-in */ }) + } + + /// Concatenates literals into a static string slice. + /// + /// This macro takes any number of comma-separated literals, yielding an + /// expression of type `&'static str` which represents all of the literals + /// concatenated left-to-right. + /// + /// Integer and floating point literals are stringified in order to be + /// concatenated. + /// + /// # Examples + /// + /// ``` + /// let s = concat!("test", 10, 'b', true); + /// assert_eq!(s, "test10btrue"); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[macro_export] + macro_rules! concat { ($($e:expr),*) => ({ /* compiler built-in */ }) } + + /// A macro which expands to the line number on which it was invoked. + /// + /// The expanded expression has type `u32`, and the returned line is not + /// the invocation of the `line!()` macro itself, but rather the first macro + /// invocation leading up to the invocation of the `line!()` macro. + /// + /// # Examples + /// + /// ``` + /// let current_line = line!(); + /// println!("defined on line: {}", current_line); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[macro_export] + macro_rules! line { () => ({ /* compiler built-in */ }) } + + /// A macro which expands to the column number on which it was invoked. + /// + /// The expanded expression has type `u32`, and the returned column is not + /// the invocation of the `column!()` macro itself, but rather the first macro + /// invocation leading up to the invocation of the `column!()` macro. + /// + /// # Examples + /// + /// ``` + /// let current_col = column!(); + /// println!("defined on column: {}", current_col); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[macro_export] + macro_rules! column { () => ({ /* compiler built-in */ }) } + + /// A macro which expands to the file name from which it was invoked. + /// + /// The expanded expression has type `&'static str`, and the returned file + /// is not the invocation of the `file!()` macro itself, but rather the + /// first macro invocation leading up to the invocation of the `file!()` + /// macro. + /// + /// # Examples + /// + /// ``` + /// let this_file = file!(); + /// println!("defined in file: {}", this_file); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[macro_export] + macro_rules! file { () => ({ /* compiler built-in */ }) } + + /// A macro which stringifies its argument. + /// + /// This macro will yield an expression of type `&'static str` which is the + /// stringification of all the tokens passed to the macro. No restrictions + /// are placed on the syntax of the macro invocation itself. + /// + /// Note that the expanded results of the input tokens may change in the + /// future. You should be careful if you rely on the output. + /// + /// # Examples + /// + /// ``` + /// let one_plus_one = stringify!(1 + 1); + /// assert_eq!(one_plus_one, "1 + 1"); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[macro_export] + macro_rules! stringify { ($t:tt) => ({ /* compiler built-in */ }) } + + /// Includes a utf8-encoded file as a string. + /// + /// The file is located relative to the current file. (similarly to how + /// modules are found) + /// + /// This macro will yield an expression of type `&'static str` which is the + /// contents of the file. + /// + /// # Examples + /// + /// ```rust,ignore + /// let secret_key = include_str!("secret-key.ascii"); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[macro_export] + macro_rules! include_str { ($file:expr) => ({ /* compiler built-in */ }) } + + /// Includes a file as a reference to a byte array. + /// + /// The file is located relative to the current file. (similarly to how + /// modules are found) + /// + /// This macro will yield an expression of type `&'static [u8; N]` which is + /// the contents of the file. + /// + /// # Examples + /// + /// ```rust,ignore + /// let secret_key = include_bytes!("secret-key.bin"); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[macro_export] + macro_rules! include_bytes { ($file:expr) => ({ /* compiler built-in */ }) } + + /// Expands to a string that represents the current module path. + /// + /// The current module path can be thought of as the hierarchy of modules + /// leading back up to the crate root. The first component of the path + /// returned is the name of the crate currently being compiled. + /// + /// # Examples + /// + /// ``` + /// mod test { + /// pub fn foo() { + /// assert!(module_path!().ends_with("test")); + /// } + /// } + /// + /// test::foo(); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[macro_export] + macro_rules! module_path { () => ({ /* compiler built-in */ }) } + + /// Boolean evaluation of configuration flags. + /// + /// In addition to the `#[cfg]` attribute, this macro is provided to allow + /// boolean expression evaluation of configuration flags. This frequently + /// leads to less duplicated code. + /// + /// The syntax given to this macro is the same syntax as [the `cfg` + /// attribute](../reference.html#conditional-compilation). + /// + /// # Examples + /// + /// ``` + /// let my_directory = if cfg!(windows) { + /// "windows-specific-directory" + /// } else { + /// "unix-directory" + /// }; + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[macro_export] + macro_rules! cfg { ($($cfg:tt)*) => ({ /* compiler built-in */ }) } + + /// Parse a file as an expression or an item according to the context. + /// + /// The file is located relative to the current file. (similarly to how + /// modules are found) + /// + /// Using this macro is often a bad idea, because if the file is + /// parsed as an expression, it is going to be placed in the + /// surrounding code unhygenically. This could result in variables + /// or functions being different from what the file expected if + /// there are variables or functions that have the same name in + /// the current file. + /// + /// # Examples + /// + /// ```ignore + /// fn foo() { + /// include!("/path/to/a/file") + /// } + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[macro_export] + macro_rules! include { ($file:expr) => ({ /* compiler built-in */ }) } +} |