1832 lines
56 KiB
Rust
1832 lines
56 KiB
Rust
// Copyright 2013-2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! Utilities for formatting and printing strings.
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#![stable(feature = "rust1", since = "1.0.0")]
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use cell::{UnsafeCell, Cell, RefCell, Ref, RefMut};
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use marker::PhantomData;
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use mem;
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use num::flt2dec;
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use ops::Deref;
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use result;
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use slice;
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use str;
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mod float;
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mod num;
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mod builders;
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#[unstable(feature = "fmt_flags_align", issue = "27726")]
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/// Possible alignments returned by `Formatter::align`
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#[derive(Debug)]
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pub enum Alignment {
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/// Indication that contents should be left-aligned.
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Left,
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/// Indication that contents should be right-aligned.
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Right,
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/// Indication that contents should be center-aligned.
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Center,
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/// No alignment was requested.
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Unknown,
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}
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#[stable(feature = "debug_builders", since = "1.2.0")]
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pub use self::builders::{DebugStruct, DebugTuple, DebugSet, DebugList, DebugMap};
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#[unstable(feature = "fmt_internals", reason = "internal to format_args!",
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issue = "0")]
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#[doc(hidden)]
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pub mod rt {
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pub mod v1;
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}
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/// The type returned by formatter methods.
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///
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/// # Examples
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///
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/// ```
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/// use std::fmt;
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///
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/// #[derive(Debug)]
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/// struct Triangle {
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/// a: f32,
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/// b: f32,
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/// c: f32
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/// }
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///
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/// impl fmt::Display for Triangle {
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/// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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/// write!(f, "({}, {}, {})", self.a, self.b, self.c)
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/// }
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/// }
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///
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/// let pythagorean_triple = Triangle { a: 3.0, b: 4.0, c: 5.0 };
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///
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/// println!("{}", pythagorean_triple);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub type Result = result::Result<(), Error>;
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/// The error type which is returned from formatting a message into a stream.
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///
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/// This type does not support transmission of an error other than that an error
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/// occurred. Any extra information must be arranged to be transmitted through
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/// some other means.
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///
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/// An important thing to remember is that the type `fmt::Error` should not be
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/// confused with [`std::io::Error`] or [`std::error::Error`], which you may also
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/// have in scope.
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///
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/// [`std::io::Error`]: ../../std/io/struct.Error.html
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/// [`std::error::Error`]: ../../std/error/trait.Error.html
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///
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/// # Examples
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///
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/// ```rust
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/// use std::fmt::{self, write};
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///
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/// let mut output = String::new();
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/// match write(&mut output, format_args!("Hello {}!", "world")) {
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/// Err(fmt::Error) => panic!("An error occurred"),
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/// _ => (),
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/// }
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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#[derive(Copy, Clone, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
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pub struct Error;
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/// A collection of methods that are required to format a message into a stream.
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///
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/// This trait is the type which this modules requires when formatting
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/// information. This is similar to the standard library's [`io::Write`] trait,
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/// but it is only intended for use in libcore.
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///
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/// This trait should generally not be implemented by consumers of the standard
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/// library. The [`write!`] macro accepts an instance of [`io::Write`], and the
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/// [`io::Write`] trait is favored over implementing this trait.
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///
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/// [`write!`]: ../../std/macro.write.html
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/// [`io::Write`]: ../../std/io/trait.Write.html
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#[stable(feature = "rust1", since = "1.0.0")]
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pub trait Write {
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/// Writes a slice of bytes into this writer, returning whether the write
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/// succeeded.
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///
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/// This method can only succeed if the entire byte slice was successfully
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/// written, and this method will not return until all data has been
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/// written or an error occurs.
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///
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/// # Errors
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///
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/// This function will return an instance of [`Error`] on error.
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///
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/// [`Error`]: struct.Error.html
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///
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/// # Examples
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///
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/// ```
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/// use std::fmt::{Error, Write};
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///
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/// fn writer<W: Write>(f: &mut W, s: &str) -> Result<(), Error> {
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/// f.write_str(s)
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/// }
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///
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/// let mut buf = String::new();
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/// writer(&mut buf, "hola").unwrap();
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/// assert_eq!(&buf, "hola");
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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fn write_str(&mut self, s: &str) -> Result;
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/// Writes a [`char`] into this writer, returning whether the write succeeded.
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///
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/// A single [`char`] may be encoded as more than one byte.
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/// This method can only succeed if the entire byte sequence was successfully
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/// written, and this method will not return until all data has been
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/// written or an error occurs.
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///
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/// # Errors
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///
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/// This function will return an instance of [`Error`] on error.
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///
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/// [`char`]: ../../std/primitive.char.html
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/// [`Error`]: struct.Error.html
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///
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/// # Examples
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///
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/// ```
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/// use std::fmt::{Error, Write};
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///
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/// fn writer<W: Write>(f: &mut W, c: char) -> Result<(), Error> {
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/// f.write_char(c)
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/// }
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///
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/// let mut buf = String::new();
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/// writer(&mut buf, 'a').unwrap();
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/// writer(&mut buf, 'b').unwrap();
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/// assert_eq!(&buf, "ab");
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/// ```
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#[stable(feature = "fmt_write_char", since = "1.1.0")]
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fn write_char(&mut self, c: char) -> Result {
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self.write_str(c.encode_utf8(&mut [0; 4]))
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}
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/// Glue for usage of the [`write!`] macro with implementors of this trait.
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///
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/// This method should generally not be invoked manually, but rather through
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/// the [`write!`] macro itself.
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///
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/// [`write!`]: ../../std/macro.write.html
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///
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/// # Examples
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///
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/// ```
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/// use std::fmt::{Error, Write};
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///
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/// fn writer<W: Write>(f: &mut W, s: &str) -> Result<(), Error> {
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/// f.write_fmt(format_args!("{}", s))
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/// }
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///
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/// let mut buf = String::new();
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/// writer(&mut buf, "world").unwrap();
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/// assert_eq!(&buf, "world");
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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fn write_fmt(&mut self, args: Arguments) -> Result {
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// This Adapter is needed to allow `self` (of type `&mut
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// Self`) to be cast to a Write (below) without
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// requiring a `Sized` bound.
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struct Adapter<'a,T: ?Sized +'a>(&'a mut T);
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impl<'a, T: ?Sized> Write for Adapter<'a, T>
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where T: Write
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{
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fn write_str(&mut self, s: &str) -> Result {
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self.0.write_str(s)
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}
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fn write_char(&mut self, c: char) -> Result {
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self.0.write_char(c)
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}
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fn write_fmt(&mut self, args: Arguments) -> Result {
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self.0.write_fmt(args)
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}
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}
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write(&mut Adapter(self), args)
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}
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}
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#[stable(feature = "fmt_write_blanket_impl", since = "1.4.0")]
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impl<'a, W: Write + ?Sized> Write for &'a mut W {
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fn write_str(&mut self, s: &str) -> Result {
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(**self).write_str(s)
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}
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fn write_char(&mut self, c: char) -> Result {
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(**self).write_char(c)
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}
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fn write_fmt(&mut self, args: Arguments) -> Result {
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(**self).write_fmt(args)
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}
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}
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/// A struct to represent both where to emit formatting strings to and how they
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/// should be formatted. A mutable version of this is passed to all formatting
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/// traits.
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#[allow(missing_debug_implementations)]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct Formatter<'a> {
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flags: u32,
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fill: char,
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align: rt::v1::Alignment,
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width: Option<usize>,
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precision: Option<usize>,
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buf: &'a mut (Write+'a),
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curarg: slice::Iter<'a, ArgumentV1<'a>>,
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args: &'a [ArgumentV1<'a>],
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}
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// NB. Argument is essentially an optimized partially applied formatting function,
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// equivalent to `exists T.(&T, fn(&T, &mut Formatter) -> Result`.
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struct Void {
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_priv: (),
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/// Erases all oibits, because `Void` erases the type of the object that
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/// will be used to produce formatted output. Since we do not know what
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/// oibits the real types have (and they can have any or none), we need to
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/// take the most conservative approach and forbid all oibits.
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///
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/// It was added after #45197 showed that one could share a `!Sync`
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/// object across threads by passing it into `format_args!`.
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_oibit_remover: PhantomData<*mut Fn()>,
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}
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/// This struct represents the generic "argument" which is taken by the Xprintf
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/// family of functions. It contains a function to format the given value. At
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/// compile time it is ensured that the function and the value have the correct
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/// types, and then this struct is used to canonicalize arguments to one type.
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#[derive(Copy)]
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#[allow(missing_debug_implementations)]
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#[unstable(feature = "fmt_internals", reason = "internal to format_args!",
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issue = "0")]
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#[doc(hidden)]
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pub struct ArgumentV1<'a> {
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value: &'a Void,
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formatter: fn(&Void, &mut Formatter) -> Result,
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}
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#[unstable(feature = "fmt_internals", reason = "internal to format_args!",
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issue = "0")]
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impl<'a> Clone for ArgumentV1<'a> {
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fn clone(&self) -> ArgumentV1<'a> {
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*self
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}
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}
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impl<'a> ArgumentV1<'a> {
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#[inline(never)]
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fn show_usize(x: &usize, f: &mut Formatter) -> Result {
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Display::fmt(x, f)
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}
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#[doc(hidden)]
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#[unstable(feature = "fmt_internals", reason = "internal to format_args!",
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issue = "0")]
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pub fn new<'b, T>(x: &'b T,
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f: fn(&T, &mut Formatter) -> Result) -> ArgumentV1<'b> {
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unsafe {
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ArgumentV1 {
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formatter: mem::transmute(f),
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value: mem::transmute(x)
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}
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}
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}
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#[doc(hidden)]
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#[unstable(feature = "fmt_internals", reason = "internal to format_args!",
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issue = "0")]
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pub fn from_usize(x: &usize) -> ArgumentV1 {
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ArgumentV1::new(x, ArgumentV1::show_usize)
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}
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fn as_usize(&self) -> Option<usize> {
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if self.formatter as usize == ArgumentV1::show_usize as usize {
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Some(unsafe { *(self.value as *const _ as *const usize) })
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} else {
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None
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}
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}
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}
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// flags available in the v1 format of format_args
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#[derive(Copy, Clone)]
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enum FlagV1 { SignPlus, SignMinus, Alternate, SignAwareZeroPad, }
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impl<'a> Arguments<'a> {
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/// When using the format_args!() macro, this function is used to generate the
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/// Arguments structure.
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#[doc(hidden)] #[inline]
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#[unstable(feature = "fmt_internals", reason = "internal to format_args!",
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issue = "0")]
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pub fn new_v1(pieces: &'a [&'a str],
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args: &'a [ArgumentV1<'a>]) -> Arguments<'a> {
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Arguments {
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pieces,
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fmt: None,
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args,
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}
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}
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|
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/// This function is used to specify nonstandard formatting parameters.
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/// The `pieces` array must be at least as long as `fmt` to construct
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/// a valid Arguments structure. Also, any `Count` within `fmt` that is
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/// `CountIsParam` or `CountIsNextParam` has to point to an argument
|
||
/// created with `argumentusize`. However, failing to do so doesn't cause
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/// unsafety, but will ignore invalid .
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||
#[doc(hidden)] #[inline]
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||
#[unstable(feature = "fmt_internals", reason = "internal to format_args!",
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issue = "0")]
|
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pub fn new_v1_formatted(pieces: &'a [&'a str],
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args: &'a [ArgumentV1<'a>],
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fmt: &'a [rt::v1::Argument]) -> Arguments<'a> {
|
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Arguments {
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pieces,
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fmt: Some(fmt),
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args,
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}
|
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}
|
||
|
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/// Estimates the length of the formatted text.
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///
|
||
/// This is intended to be used for setting initial `String` capacity
|
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/// when using `format!`. Note: this is neither the lower nor upper bound.
|
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#[doc(hidden)] #[inline]
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#[unstable(feature = "fmt_internals", reason = "internal to format_args!",
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issue = "0")]
|
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pub fn estimated_capacity(&self) -> usize {
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let pieces_length: usize = self.pieces.iter()
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.map(|x| x.len()).sum();
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||
|
||
if self.args.is_empty() {
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pieces_length
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} else if self.pieces[0] == "" && pieces_length < 16 {
|
||
// If the format string starts with an argument,
|
||
// don't preallocate anything, unless length
|
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// of pieces is significant.
|
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0
|
||
} else {
|
||
// There are some arguments, so any additional push
|
||
// will reallocate the string. To avoid that,
|
||
// we're "pre-doubling" the capacity here.
|
||
pieces_length.checked_mul(2).unwrap_or(0)
|
||
}
|
||
}
|
||
}
|
||
|
||
/// This structure represents a safely precompiled version of a format string
|
||
/// and its arguments. This cannot be generated at runtime because it cannot
|
||
/// safely be done, so no constructors are given and the fields are private
|
||
/// to prevent modification.
|
||
///
|
||
/// The [`format_args!`] macro will safely create an instance of this structure
|
||
/// and pass it to a function or closure, passed as the first argument. The
|
||
/// macro validates the format string at compile-time so usage of the [`write`]
|
||
/// and [`format`] functions can be safely performed.
|
||
///
|
||
/// [`format_args!`]: ../../std/macro.format_args.html
|
||
/// [`format`]: ../../std/fmt/fn.format.html
|
||
/// [`write`]: ../../std/fmt/fn.write.html
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[derive(Copy, Clone)]
|
||
pub struct Arguments<'a> {
|
||
// Format string pieces to print.
|
||
pieces: &'a [&'a str],
|
||
|
||
// Placeholder specs, or `None` if all specs are default (as in "{}{}").
|
||
fmt: Option<&'a [rt::v1::Argument]>,
|
||
|
||
// Dynamic arguments for interpolation, to be interleaved with string
|
||
// pieces. (Every argument is preceded by a string piece.)
|
||
args: &'a [ArgumentV1<'a>],
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a> Debug for Arguments<'a> {
|
||
fn fmt(&self, fmt: &mut Formatter) -> Result {
|
||
Display::fmt(self, fmt)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a> Display for Arguments<'a> {
|
||
fn fmt(&self, fmt: &mut Formatter) -> Result {
|
||
write(fmt.buf, *self)
|
||
}
|
||
}
|
||
|
||
/// `?` formatting.
|
||
///
|
||
/// `Debug` should format the output in a programmer-facing, debugging context.
|
||
///
|
||
/// Generally speaking, you should just `derive` a `Debug` implementation.
|
||
///
|
||
/// When used with the alternate format specifier `#?`, the output is pretty-printed.
|
||
///
|
||
/// For more information on formatters, see [the module-level documentation][module].
|
||
///
|
||
/// [module]: ../../std/fmt/index.html
|
||
///
|
||
/// This trait can be used with `#[derive]` if all fields implement `Debug`. When
|
||
/// `derive`d for structs, it will use the name of the `struct`, then `{`, then a
|
||
/// comma-separated list of each field's name and `Debug` value, then `}`. For
|
||
/// `enum`s, it will use the name of the variant and, if applicable, `(`, then the
|
||
/// `Debug` values of the fields, then `)`.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Deriving an implementation:
|
||
///
|
||
/// ```
|
||
/// #[derive(Debug)]
|
||
/// struct Point {
|
||
/// x: i32,
|
||
/// y: i32,
|
||
/// }
|
||
///
|
||
/// let origin = Point { x: 0, y: 0 };
|
||
///
|
||
/// println!("The origin is: {:?}", origin);
|
||
/// ```
|
||
///
|
||
/// Manually implementing:
|
||
///
|
||
/// ```
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Point {
|
||
/// x: i32,
|
||
/// y: i32,
|
||
/// }
|
||
///
|
||
/// impl fmt::Debug for Point {
|
||
/// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
/// write!(f, "Point {{ x: {}, y: {} }}", self.x, self.y)
|
||
/// }
|
||
/// }
|
||
///
|
||
/// let origin = Point { x: 0, y: 0 };
|
||
///
|
||
/// println!("The origin is: {:?}", origin);
|
||
/// ```
|
||
///
|
||
/// This outputs:
|
||
///
|
||
/// ```text
|
||
/// The origin is: Point { x: 0, y: 0 }
|
||
/// ```
|
||
///
|
||
/// There are a number of `debug_*` methods on [`Formatter`] to help you with manual
|
||
/// implementations, such as [`debug_struct`][debug_struct].
|
||
///
|
||
/// `Debug` implementations using either `derive` or the debug builder API
|
||
/// on [`Formatter`] support pretty printing using the alternate flag: `{:#?}`.
|
||
///
|
||
/// [debug_struct]: ../../std/fmt/struct.Formatter.html#method.debug_struct
|
||
/// [`Formatter`]: ../../std/fmt/struct.Formatter.html
|
||
///
|
||
/// Pretty printing with `#?`:
|
||
///
|
||
/// ```
|
||
/// #[derive(Debug)]
|
||
/// struct Point {
|
||
/// x: i32,
|
||
/// y: i32,
|
||
/// }
|
||
///
|
||
/// let origin = Point { x: 0, y: 0 };
|
||
///
|
||
/// println!("The origin is: {:#?}", origin);
|
||
/// ```
|
||
///
|
||
/// This outputs:
|
||
///
|
||
/// ```text
|
||
/// The origin is: Point {
|
||
/// x: 0,
|
||
/// y: 0
|
||
/// }
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[rustc_on_unimplemented(
|
||
on(crate_local, label="`{Self}` cannot be formatted using `:?`; \
|
||
add `#[derive(Debug)]` or manually implement `{Debug}`"),
|
||
message="`{Self}` doesn't implement `{Debug}`",
|
||
label="`{Self}` cannot be formatted using `:?` because it doesn't implement `{Debug}`",
|
||
)]
|
||
#[lang = "debug_trait"]
|
||
pub trait Debug {
|
||
/// Formats the value using the given formatter.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Position {
|
||
/// longitude: f32,
|
||
/// latitude: f32,
|
||
/// }
|
||
///
|
||
/// impl fmt::Debug for Position {
|
||
/// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
/// write!(f, "({:?}, {:?})", self.longitude, self.latitude)
|
||
/// }
|
||
/// }
|
||
///
|
||
/// assert_eq!("(1.987, 2.983)".to_owned(),
|
||
/// format!("{:?}", Position { longitude: 1.987, latitude: 2.983, }));
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
fn fmt(&self, f: &mut Formatter) -> Result;
|
||
}
|
||
|
||
/// Format trait for an empty format, `{}`.
|
||
///
|
||
/// `Display` is similar to [`Debug`][debug], but `Display` is for user-facing
|
||
/// output, and so cannot be derived.
|
||
///
|
||
/// [debug]: trait.Debug.html
|
||
///
|
||
/// For more information on formatters, see [the module-level documentation][module].
|
||
///
|
||
/// [module]: ../../std/fmt/index.html
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Implementing `Display` on a type:
|
||
///
|
||
/// ```
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Point {
|
||
/// x: i32,
|
||
/// y: i32,
|
||
/// }
|
||
///
|
||
/// impl fmt::Display for Point {
|
||
/// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
/// write!(f, "({}, {})", self.x, self.y)
|
||
/// }
|
||
/// }
|
||
///
|
||
/// let origin = Point { x: 0, y: 0 };
|
||
///
|
||
/// println!("The origin is: {}", origin);
|
||
/// ```
|
||
#[rustc_on_unimplemented(
|
||
message="`{Self}` doesn't implement `{Display}`",
|
||
label="`{Self}` cannot be formatted with the default formatter; \
|
||
try using `:?` instead if you are using a format string",
|
||
)]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub trait Display {
|
||
/// Formats the value using the given formatter.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Position {
|
||
/// longitude: f32,
|
||
/// latitude: f32,
|
||
/// }
|
||
///
|
||
/// impl fmt::Display for Position {
|
||
/// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
/// write!(f, "({}, {})", self.longitude, self.latitude)
|
||
/// }
|
||
/// }
|
||
///
|
||
/// assert_eq!("(1.987, 2.983)".to_owned(),
|
||
/// format!("{}", Position { longitude: 1.987, latitude: 2.983, }));
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
fn fmt(&self, f: &mut Formatter) -> Result;
|
||
}
|
||
|
||
/// `o` formatting.
|
||
///
|
||
/// The `Octal` trait should format its output as a number in base-8.
|
||
///
|
||
/// For primitive signed integers (`i8` to `i128`, and `isize`),
|
||
/// negative values are formatted as the two’s complement representation.
|
||
///
|
||
/// The alternate flag, `#`, adds a `0o` in front of the output.
|
||
///
|
||
/// For more information on formatters, see [the module-level documentation][module].
|
||
///
|
||
/// [module]: ../../std/fmt/index.html
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage with `i32`:
|
||
///
|
||
/// ```
|
||
/// let x = 42; // 42 is '52' in octal
|
||
///
|
||
/// assert_eq!(format!("{:o}", x), "52");
|
||
/// assert_eq!(format!("{:#o}", x), "0o52");
|
||
///
|
||
/// assert_eq!(format!("{:o}", -16), "37777777760");
|
||
/// ```
|
||
///
|
||
/// Implementing `Octal` on a type:
|
||
///
|
||
/// ```
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Length(i32);
|
||
///
|
||
/// impl fmt::Octal for Length {
|
||
/// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
/// let val = self.0;
|
||
///
|
||
/// write!(f, "{:o}", val) // delegate to i32's implementation
|
||
/// }
|
||
/// }
|
||
///
|
||
/// let l = Length(9);
|
||
///
|
||
/// println!("l as octal is: {:o}", l);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub trait Octal {
|
||
/// Formats the value using the given formatter.
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
fn fmt(&self, f: &mut Formatter) -> Result;
|
||
}
|
||
|
||
/// `b` formatting.
|
||
///
|
||
/// The `Binary` trait should format its output as a number in binary.
|
||
///
|
||
/// For primitive signed integers ([`i8`] to [`i128`], and [`isize`]),
|
||
/// negative values are formatted as the two’s complement representation.
|
||
///
|
||
/// The alternate flag, `#`, adds a `0b` in front of the output.
|
||
///
|
||
/// For more information on formatters, see [the module-level documentation][module].
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage with [`i32`]:
|
||
///
|
||
/// ```
|
||
/// let x = 42; // 42 is '101010' in binary
|
||
///
|
||
/// assert_eq!(format!("{:b}", x), "101010");
|
||
/// assert_eq!(format!("{:#b}", x), "0b101010");
|
||
///
|
||
/// assert_eq!(format!("{:b}", -16), "11111111111111111111111111110000");
|
||
/// ```
|
||
///
|
||
/// Implementing `Binary` on a type:
|
||
///
|
||
/// ```
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Length(i32);
|
||
///
|
||
/// impl fmt::Binary for Length {
|
||
/// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
/// let val = self.0;
|
||
///
|
||
/// write!(f, "{:b}", val) // delegate to i32's implementation
|
||
/// }
|
||
/// }
|
||
///
|
||
/// let l = Length(107);
|
||
///
|
||
/// println!("l as binary is: {:b}", l);
|
||
/// ```
|
||
///
|
||
/// [module]: ../../std/fmt/index.html
|
||
/// [`i8`]: ../../std/primitive.i8.html
|
||
/// [`i128`]: ../../std/primitive.i128.html
|
||
/// [`isize`]: ../../std/primitive.isize.html
|
||
/// [`i32`]: ../../std/primitive.i32.html
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub trait Binary {
|
||
/// Formats the value using the given formatter.
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
fn fmt(&self, f: &mut Formatter) -> Result;
|
||
}
|
||
|
||
/// `x` formatting.
|
||
///
|
||
/// The `LowerHex` trait should format its output as a number in hexadecimal, with `a` through `f`
|
||
/// in lower case.
|
||
///
|
||
/// For primitive signed integers (`i8` to `i128`, and `isize`),
|
||
/// negative values are formatted as the two’s complement representation.
|
||
///
|
||
/// The alternate flag, `#`, adds a `0x` in front of the output.
|
||
///
|
||
/// For more information on formatters, see [the module-level documentation][module].
|
||
///
|
||
/// [module]: ../../std/fmt/index.html
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage with `i32`:
|
||
///
|
||
/// ```
|
||
/// let x = 42; // 42 is '2a' in hex
|
||
///
|
||
/// assert_eq!(format!("{:x}", x), "2a");
|
||
/// assert_eq!(format!("{:#x}", x), "0x2a");
|
||
///
|
||
/// assert_eq!(format!("{:x}", -16), "fffffff0");
|
||
/// ```
|
||
///
|
||
/// Implementing `LowerHex` on a type:
|
||
///
|
||
/// ```
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Length(i32);
|
||
///
|
||
/// impl fmt::LowerHex for Length {
|
||
/// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
/// let val = self.0;
|
||
///
|
||
/// write!(f, "{:x}", val) // delegate to i32's implementation
|
||
/// }
|
||
/// }
|
||
///
|
||
/// let l = Length(9);
|
||
///
|
||
/// println!("l as hex is: {:x}", l);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub trait LowerHex {
|
||
/// Formats the value using the given formatter.
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
fn fmt(&self, f: &mut Formatter) -> Result;
|
||
}
|
||
|
||
/// `X` formatting.
|
||
///
|
||
/// The `UpperHex` trait should format its output as a number in hexadecimal, with `A` through `F`
|
||
/// in upper case.
|
||
///
|
||
/// For primitive signed integers (`i8` to `i128`, and `isize`),
|
||
/// negative values are formatted as the two’s complement representation.
|
||
///
|
||
/// The alternate flag, `#`, adds a `0x` in front of the output.
|
||
///
|
||
/// For more information on formatters, see [the module-level documentation][module].
|
||
///
|
||
/// [module]: ../../std/fmt/index.html
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage with `i32`:
|
||
///
|
||
/// ```
|
||
/// let x = 42; // 42 is '2A' in hex
|
||
///
|
||
/// assert_eq!(format!("{:X}", x), "2A");
|
||
/// assert_eq!(format!("{:#X}", x), "0x2A");
|
||
///
|
||
/// assert_eq!(format!("{:X}", -16), "FFFFFFF0");
|
||
/// ```
|
||
///
|
||
/// Implementing `UpperHex` on a type:
|
||
///
|
||
/// ```
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Length(i32);
|
||
///
|
||
/// impl fmt::UpperHex for Length {
|
||
/// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
/// let val = self.0;
|
||
///
|
||
/// write!(f, "{:X}", val) // delegate to i32's implementation
|
||
/// }
|
||
/// }
|
||
///
|
||
/// let l = Length(9);
|
||
///
|
||
/// println!("l as hex is: {:X}", l);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub trait UpperHex {
|
||
/// Formats the value using the given formatter.
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
fn fmt(&self, f: &mut Formatter) -> Result;
|
||
}
|
||
|
||
/// `p` formatting.
|
||
///
|
||
/// The `Pointer` trait should format its output as a memory location. This is commonly presented
|
||
/// as hexadecimal.
|
||
///
|
||
/// For more information on formatters, see [the module-level documentation][module].
|
||
///
|
||
/// [module]: ../../std/fmt/index.html
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage with `&i32`:
|
||
///
|
||
/// ```
|
||
/// let x = &42;
|
||
///
|
||
/// let address = format!("{:p}", x); // this produces something like '0x7f06092ac6d0'
|
||
/// ```
|
||
///
|
||
/// Implementing `Pointer` on a type:
|
||
///
|
||
/// ```
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Length(i32);
|
||
///
|
||
/// impl fmt::Pointer for Length {
|
||
/// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
/// // use `as` to convert to a `*const T`, which implements Pointer, which we can use
|
||
///
|
||
/// write!(f, "{:p}", self as *const Length)
|
||
/// }
|
||
/// }
|
||
///
|
||
/// let l = Length(42);
|
||
///
|
||
/// println!("l is in memory here: {:p}", l);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub trait Pointer {
|
||
/// Formats the value using the given formatter.
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
fn fmt(&self, f: &mut Formatter) -> Result;
|
||
}
|
||
|
||
/// `e` formatting.
|
||
///
|
||
/// The `LowerExp` trait should format its output in scientific notation with a lower-case `e`.
|
||
///
|
||
/// For more information on formatters, see [the module-level documentation][module].
|
||
///
|
||
/// [module]: ../../std/fmt/index.html
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage with `i32`:
|
||
///
|
||
/// ```
|
||
/// let x = 42.0; // 42.0 is '4.2e1' in scientific notation
|
||
///
|
||
/// assert_eq!(format!("{:e}", x), "4.2e1");
|
||
/// ```
|
||
///
|
||
/// Implementing `LowerExp` on a type:
|
||
///
|
||
/// ```
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Length(i32);
|
||
///
|
||
/// impl fmt::LowerExp for Length {
|
||
/// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
/// let val = self.0;
|
||
/// write!(f, "{}e1", val / 10)
|
||
/// }
|
||
/// }
|
||
///
|
||
/// let l = Length(100);
|
||
///
|
||
/// println!("l in scientific notation is: {:e}", l);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub trait LowerExp {
|
||
/// Formats the value using the given formatter.
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
fn fmt(&self, f: &mut Formatter) -> Result;
|
||
}
|
||
|
||
/// `E` formatting.
|
||
///
|
||
/// The `UpperExp` trait should format its output in scientific notation with an upper-case `E`.
|
||
///
|
||
/// For more information on formatters, see [the module-level documentation][module].
|
||
///
|
||
/// [module]: ../../std/fmt/index.html
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage with `f32`:
|
||
///
|
||
/// ```
|
||
/// let x = 42.0; // 42.0 is '4.2E1' in scientific notation
|
||
///
|
||
/// assert_eq!(format!("{:E}", x), "4.2E1");
|
||
/// ```
|
||
///
|
||
/// Implementing `UpperExp` on a type:
|
||
///
|
||
/// ```
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Length(i32);
|
||
///
|
||
/// impl fmt::UpperExp for Length {
|
||
/// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
/// let val = self.0;
|
||
/// write!(f, "{}E1", val / 10)
|
||
/// }
|
||
/// }
|
||
///
|
||
/// let l = Length(100);
|
||
///
|
||
/// println!("l in scientific notation is: {:E}", l);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub trait UpperExp {
|
||
/// Formats the value using the given formatter.
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
fn fmt(&self, f: &mut Formatter) -> Result;
|
||
}
|
||
|
||
/// The `write` function takes an output stream, and an `Arguments` struct
|
||
/// that can be precompiled with the `format_args!` macro.
|
||
///
|
||
/// The arguments will be formatted according to the specified format string
|
||
/// into the output stream provided.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// use std::fmt;
|
||
///
|
||
/// let mut output = String::new();
|
||
/// fmt::write(&mut output, format_args!("Hello {}!", "world"))
|
||
/// .expect("Error occurred while trying to write in String");
|
||
/// assert_eq!(output, "Hello world!");
|
||
/// ```
|
||
///
|
||
/// Please note that using [`write!`] might be preferable. Example:
|
||
///
|
||
/// ```
|
||
/// use std::fmt::Write;
|
||
///
|
||
/// let mut output = String::new();
|
||
/// write!(&mut output, "Hello {}!", "world")
|
||
/// .expect("Error occurred while trying to write in String");
|
||
/// assert_eq!(output, "Hello world!");
|
||
/// ```
|
||
///
|
||
/// [`write!`]: ../../std/macro.write.html
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn write(output: &mut Write, args: Arguments) -> Result {
|
||
let mut formatter = Formatter {
|
||
flags: 0,
|
||
width: None,
|
||
precision: None,
|
||
buf: output,
|
||
align: rt::v1::Alignment::Unknown,
|
||
fill: ' ',
|
||
args: args.args,
|
||
curarg: args.args.iter(),
|
||
};
|
||
|
||
let mut pieces = args.pieces.iter();
|
||
|
||
match args.fmt {
|
||
None => {
|
||
// We can use default formatting parameters for all arguments.
|
||
for (arg, piece) in args.args.iter().zip(pieces.by_ref()) {
|
||
formatter.buf.write_str(*piece)?;
|
||
(arg.formatter)(arg.value, &mut formatter)?;
|
||
}
|
||
}
|
||
Some(fmt) => {
|
||
// Every spec has a corresponding argument that is preceded by
|
||
// a string piece.
|
||
for (arg, piece) in fmt.iter().zip(pieces.by_ref()) {
|
||
formatter.buf.write_str(*piece)?;
|
||
formatter.run(arg)?;
|
||
}
|
||
}
|
||
}
|
||
|
||
// There can be only one trailing string piece left.
|
||
if let Some(piece) = pieces.next() {
|
||
formatter.buf.write_str(*piece)?;
|
||
}
|
||
|
||
Ok(())
|
||
}
|
||
|
||
impl<'a> Formatter<'a> {
|
||
fn wrap_buf<'b, 'c, F>(&'b mut self, wrap: F) -> Formatter<'c>
|
||
where 'b: 'c, F: FnOnce(&'b mut (Write+'b)) -> &'c mut (Write+'c)
|
||
{
|
||
Formatter {
|
||
// We want to change this
|
||
buf: wrap(self.buf),
|
||
|
||
// And preserve these
|
||
flags: self.flags,
|
||
fill: self.fill,
|
||
align: self.align,
|
||
width: self.width,
|
||
precision: self.precision,
|
||
|
||
// These only exist in the struct for the `run` method,
|
||
// which won’t be used together with this method.
|
||
curarg: self.curarg.clone(),
|
||
args: self.args,
|
||
}
|
||
}
|
||
|
||
// First up is the collection of functions used to execute a format string
|
||
// at runtime. This consumes all of the compile-time statics generated by
|
||
// the format! syntax extension.
|
||
fn run(&mut self, arg: &rt::v1::Argument) -> Result {
|
||
// Fill in the format parameters into the formatter
|
||
self.fill = arg.format.fill;
|
||
self.align = arg.format.align;
|
||
self.flags = arg.format.flags;
|
||
self.width = self.getcount(&arg.format.width);
|
||
self.precision = self.getcount(&arg.format.precision);
|
||
|
||
// Extract the correct argument
|
||
let value = match arg.position {
|
||
rt::v1::Position::Next => { *self.curarg.next().unwrap() }
|
||
rt::v1::Position::At(i) => self.args[i],
|
||
};
|
||
|
||
// Then actually do some printing
|
||
(value.formatter)(value.value, self)
|
||
}
|
||
|
||
fn getcount(&mut self, cnt: &rt::v1::Count) -> Option<usize> {
|
||
match *cnt {
|
||
rt::v1::Count::Is(n) => Some(n),
|
||
rt::v1::Count::Implied => None,
|
||
rt::v1::Count::Param(i) => {
|
||
self.args[i].as_usize()
|
||
}
|
||
rt::v1::Count::NextParam => {
|
||
self.curarg.next().and_then(|arg| arg.as_usize())
|
||
}
|
||
}
|
||
}
|
||
|
||
// Helper methods used for padding and processing formatting arguments that
|
||
// all formatting traits can use.
|
||
|
||
/// Performs the correct padding for an integer which has already been
|
||
/// emitted into a str. The str should *not* contain the sign for the
|
||
/// integer, that will be added by this method.
|
||
///
|
||
/// # Arguments
|
||
///
|
||
/// * is_nonnegative - whether the original integer was either positive or zero.
|
||
/// * prefix - if the '#' character (Alternate) is provided, this
|
||
/// is the prefix to put in front of the number.
|
||
/// * buf - the byte array that the number has been formatted into
|
||
///
|
||
/// This function will correctly account for the flags provided as well as
|
||
/// the minimum width. It will not take precision into account.
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn pad_integral(&mut self,
|
||
is_nonnegative: bool,
|
||
prefix: &str,
|
||
buf: &str)
|
||
-> Result {
|
||
let mut width = buf.len();
|
||
|
||
let mut sign = None;
|
||
if !is_nonnegative {
|
||
sign = Some('-'); width += 1;
|
||
} else if self.sign_plus() {
|
||
sign = Some('+'); width += 1;
|
||
}
|
||
|
||
let mut prefixed = false;
|
||
if self.alternate() {
|
||
prefixed = true; width += prefix.chars().count();
|
||
}
|
||
|
||
// Writes the sign if it exists, and then the prefix if it was requested
|
||
let write_prefix = |f: &mut Formatter| {
|
||
if let Some(c) = sign {
|
||
f.buf.write_str(c.encode_utf8(&mut [0; 4]))?;
|
||
}
|
||
if prefixed { f.buf.write_str(prefix) }
|
||
else { Ok(()) }
|
||
};
|
||
|
||
// The `width` field is more of a `min-width` parameter at this point.
|
||
match self.width {
|
||
// If there's no minimum length requirements then we can just
|
||
// write the bytes.
|
||
None => {
|
||
write_prefix(self)?; self.buf.write_str(buf)
|
||
}
|
||
// Check if we're over the minimum width, if so then we can also
|
||
// just write the bytes.
|
||
Some(min) if width >= min => {
|
||
write_prefix(self)?; self.buf.write_str(buf)
|
||
}
|
||
// The sign and prefix goes before the padding if the fill character
|
||
// is zero
|
||
Some(min) if self.sign_aware_zero_pad() => {
|
||
self.fill = '0';
|
||
self.align = rt::v1::Alignment::Right;
|
||
write_prefix(self)?;
|
||
self.with_padding(min - width, rt::v1::Alignment::Right, |f| {
|
||
f.buf.write_str(buf)
|
||
})
|
||
}
|
||
// Otherwise, the sign and prefix goes after the padding
|
||
Some(min) => {
|
||
self.with_padding(min - width, rt::v1::Alignment::Right, |f| {
|
||
write_prefix(f)?; f.buf.write_str(buf)
|
||
})
|
||
}
|
||
}
|
||
}
|
||
|
||
/// This function takes a string slice and emits it to the internal buffer
|
||
/// after applying the relevant formatting flags specified. The flags
|
||
/// recognized for generic strings are:
|
||
///
|
||
/// * width - the minimum width of what to emit
|
||
/// * fill/align - what to emit and where to emit it if the string
|
||
/// provided needs to be padded
|
||
/// * precision - the maximum length to emit, the string is truncated if it
|
||
/// is longer than this length
|
||
///
|
||
/// Notably this function ignores the `flag` parameters.
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn pad(&mut self, s: &str) -> Result {
|
||
// Make sure there's a fast path up front
|
||
if self.width.is_none() && self.precision.is_none() {
|
||
return self.buf.write_str(s);
|
||
}
|
||
// The `precision` field can be interpreted as a `max-width` for the
|
||
// string being formatted.
|
||
let s = if let Some(max) = self.precision {
|
||
// If our string is longer that the precision, then we must have
|
||
// truncation. However other flags like `fill`, `width` and `align`
|
||
// must act as always.
|
||
if let Some((i, _)) = s.char_indices().skip(max).next() {
|
||
&s[..i]
|
||
} else {
|
||
&s
|
||
}
|
||
} else {
|
||
&s
|
||
};
|
||
// The `width` field is more of a `min-width` parameter at this point.
|
||
match self.width {
|
||
// If we're under the maximum length, and there's no minimum length
|
||
// requirements, then we can just emit the string
|
||
None => self.buf.write_str(s),
|
||
// If we're under the maximum width, check if we're over the minimum
|
||
// width, if so it's as easy as just emitting the string.
|
||
Some(width) if s.chars().count() >= width => {
|
||
self.buf.write_str(s)
|
||
}
|
||
// If we're under both the maximum and the minimum width, then fill
|
||
// up the minimum width with the specified string + some alignment.
|
||
Some(width) => {
|
||
let align = rt::v1::Alignment::Left;
|
||
self.with_padding(width - s.chars().count(), align, |me| {
|
||
me.buf.write_str(s)
|
||
})
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Runs a callback, emitting the correct padding either before or
|
||
/// afterwards depending on whether right or left alignment is requested.
|
||
fn with_padding<F>(&mut self, padding: usize, default: rt::v1::Alignment,
|
||
f: F) -> Result
|
||
where F: FnOnce(&mut Formatter) -> Result,
|
||
{
|
||
let align = match self.align {
|
||
rt::v1::Alignment::Unknown => default,
|
||
_ => self.align
|
||
};
|
||
|
||
let (pre_pad, post_pad) = match align {
|
||
rt::v1::Alignment::Left => (0, padding),
|
||
rt::v1::Alignment::Right |
|
||
rt::v1::Alignment::Unknown => (padding, 0),
|
||
rt::v1::Alignment::Center => (padding / 2, (padding + 1) / 2),
|
||
};
|
||
|
||
let mut fill = [0; 4];
|
||
let fill = self.fill.encode_utf8(&mut fill);
|
||
|
||
for _ in 0..pre_pad {
|
||
self.buf.write_str(fill)?;
|
||
}
|
||
|
||
f(self)?;
|
||
|
||
for _ in 0..post_pad {
|
||
self.buf.write_str(fill)?;
|
||
}
|
||
|
||
Ok(())
|
||
}
|
||
|
||
/// Takes the formatted parts and applies the padding.
|
||
/// Assumes that the caller already has rendered the parts with required precision,
|
||
/// so that `self.precision` can be ignored.
|
||
fn pad_formatted_parts(&mut self, formatted: &flt2dec::Formatted) -> Result {
|
||
if let Some(mut width) = self.width {
|
||
// for the sign-aware zero padding, we render the sign first and
|
||
// behave as if we had no sign from the beginning.
|
||
let mut formatted = formatted.clone();
|
||
let old_fill = self.fill;
|
||
let old_align = self.align;
|
||
let mut align = old_align;
|
||
if self.sign_aware_zero_pad() {
|
||
// a sign always goes first
|
||
let sign = unsafe { str::from_utf8_unchecked(formatted.sign) };
|
||
self.buf.write_str(sign)?;
|
||
|
||
// remove the sign from the formatted parts
|
||
formatted.sign = b"";
|
||
width = if width < sign.len() { 0 } else { width - sign.len() };
|
||
align = rt::v1::Alignment::Right;
|
||
self.fill = '0';
|
||
self.align = rt::v1::Alignment::Right;
|
||
}
|
||
|
||
// remaining parts go through the ordinary padding process.
|
||
let len = formatted.len();
|
||
let ret = if width <= len { // no padding
|
||
self.write_formatted_parts(&formatted)
|
||
} else {
|
||
self.with_padding(width - len, align, |f| {
|
||
f.write_formatted_parts(&formatted)
|
||
})
|
||
};
|
||
self.fill = old_fill;
|
||
self.align = old_align;
|
||
ret
|
||
} else {
|
||
// this is the common case and we take a shortcut
|
||
self.write_formatted_parts(formatted)
|
||
}
|
||
}
|
||
|
||
fn write_formatted_parts(&mut self, formatted: &flt2dec::Formatted) -> Result {
|
||
fn write_bytes(buf: &mut Write, s: &[u8]) -> Result {
|
||
buf.write_str(unsafe { str::from_utf8_unchecked(s) })
|
||
}
|
||
|
||
if !formatted.sign.is_empty() {
|
||
write_bytes(self.buf, formatted.sign)?;
|
||
}
|
||
for part in formatted.parts {
|
||
match *part {
|
||
flt2dec::Part::Zero(mut nzeroes) => {
|
||
const ZEROES: &'static str = // 64 zeroes
|
||
"0000000000000000000000000000000000000000000000000000000000000000";
|
||
while nzeroes > ZEROES.len() {
|
||
self.buf.write_str(ZEROES)?;
|
||
nzeroes -= ZEROES.len();
|
||
}
|
||
if nzeroes > 0 {
|
||
self.buf.write_str(&ZEROES[..nzeroes])?;
|
||
}
|
||
}
|
||
flt2dec::Part::Num(mut v) => {
|
||
let mut s = [0; 5];
|
||
let len = part.len();
|
||
for c in s[..len].iter_mut().rev() {
|
||
*c = b'0' + (v % 10) as u8;
|
||
v /= 10;
|
||
}
|
||
write_bytes(self.buf, &s[..len])?;
|
||
}
|
||
flt2dec::Part::Copy(buf) => {
|
||
write_bytes(self.buf, buf)?;
|
||
}
|
||
}
|
||
}
|
||
Ok(())
|
||
}
|
||
|
||
/// Writes some data to the underlying buffer contained within this
|
||
/// formatter.
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn write_str(&mut self, data: &str) -> Result {
|
||
self.buf.write_str(data)
|
||
}
|
||
|
||
/// Writes some formatted information into this instance
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn write_fmt(&mut self, fmt: Arguments) -> Result {
|
||
write(self.buf, fmt)
|
||
}
|
||
|
||
/// Flags for formatting
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[rustc_deprecated(since = "1.24.0",
|
||
reason = "use the `sign_plus`, `sign_minus`, `alternate`, \
|
||
or `sign_aware_zero_pad` methods instead")]
|
||
pub fn flags(&self) -> u32 { self.flags }
|
||
|
||
/// Character used as 'fill' whenever there is alignment
|
||
#[stable(feature = "fmt_flags", since = "1.5.0")]
|
||
pub fn fill(&self) -> char { self.fill }
|
||
|
||
/// Flag indicating what form of alignment was requested
|
||
#[unstable(feature = "fmt_flags_align", reason = "method was just created",
|
||
issue = "27726")]
|
||
pub fn align(&self) -> Alignment {
|
||
match self.align {
|
||
rt::v1::Alignment::Left => Alignment::Left,
|
||
rt::v1::Alignment::Right => Alignment::Right,
|
||
rt::v1::Alignment::Center => Alignment::Center,
|
||
rt::v1::Alignment::Unknown => Alignment::Unknown,
|
||
}
|
||
}
|
||
|
||
/// Optionally specified integer width that the output should be
|
||
#[stable(feature = "fmt_flags", since = "1.5.0")]
|
||
pub fn width(&self) -> Option<usize> { self.width }
|
||
|
||
/// Optionally specified precision for numeric types
|
||
#[stable(feature = "fmt_flags", since = "1.5.0")]
|
||
pub fn precision(&self) -> Option<usize> { self.precision }
|
||
|
||
/// Determines if the `+` flag was specified.
|
||
#[stable(feature = "fmt_flags", since = "1.5.0")]
|
||
pub fn sign_plus(&self) -> bool { self.flags & (1 << FlagV1::SignPlus as u32) != 0 }
|
||
|
||
/// Determines if the `-` flag was specified.
|
||
#[stable(feature = "fmt_flags", since = "1.5.0")]
|
||
pub fn sign_minus(&self) -> bool { self.flags & (1 << FlagV1::SignMinus as u32) != 0 }
|
||
|
||
/// Determines if the `#` flag was specified.
|
||
#[stable(feature = "fmt_flags", since = "1.5.0")]
|
||
pub fn alternate(&self) -> bool { self.flags & (1 << FlagV1::Alternate as u32) != 0 }
|
||
|
||
/// Determines if the `0` flag was specified.
|
||
#[stable(feature = "fmt_flags", since = "1.5.0")]
|
||
pub fn sign_aware_zero_pad(&self) -> bool {
|
||
self.flags & (1 << FlagV1::SignAwareZeroPad as u32) != 0
|
||
}
|
||
|
||
/// Creates a [`DebugStruct`] builder designed to assist with creation of
|
||
/// [`fmt::Debug`] implementations for structs.
|
||
///
|
||
/// [`DebugStruct`]: ../../std/fmt/struct.DebugStruct.html
|
||
/// [`fmt::Debug`]: ../../std/fmt/trait.Debug.html
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```rust
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Foo {
|
||
/// bar: i32,
|
||
/// baz: String,
|
||
/// }
|
||
///
|
||
/// impl fmt::Debug for Foo {
|
||
/// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
|
||
/// fmt.debug_struct("Foo")
|
||
/// .field("bar", &self.bar)
|
||
/// .field("baz", &self.baz)
|
||
/// .finish()
|
||
/// }
|
||
/// }
|
||
///
|
||
/// // prints "Foo { bar: 10, baz: "Hello World" }"
|
||
/// println!("{:?}", Foo { bar: 10, baz: "Hello World".to_string() });
|
||
/// ```
|
||
#[stable(feature = "debug_builders", since = "1.2.0")]
|
||
pub fn debug_struct<'b>(&'b mut self, name: &str) -> DebugStruct<'b, 'a> {
|
||
builders::debug_struct_new(self, name)
|
||
}
|
||
|
||
/// Creates a `DebugTuple` builder designed to assist with creation of
|
||
/// `fmt::Debug` implementations for tuple structs.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```rust
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Foo(i32, String);
|
||
///
|
||
/// impl fmt::Debug for Foo {
|
||
/// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
|
||
/// fmt.debug_tuple("Foo")
|
||
/// .field(&self.0)
|
||
/// .field(&self.1)
|
||
/// .finish()
|
||
/// }
|
||
/// }
|
||
///
|
||
/// // prints "Foo(10, "Hello World")"
|
||
/// println!("{:?}", Foo(10, "Hello World".to_string()));
|
||
/// ```
|
||
#[stable(feature = "debug_builders", since = "1.2.0")]
|
||
pub fn debug_tuple<'b>(&'b mut self, name: &str) -> DebugTuple<'b, 'a> {
|
||
builders::debug_tuple_new(self, name)
|
||
}
|
||
|
||
/// Creates a `DebugList` builder designed to assist with creation of
|
||
/// `fmt::Debug` implementations for list-like structures.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```rust
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Foo(Vec<i32>);
|
||
///
|
||
/// impl fmt::Debug for Foo {
|
||
/// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
|
||
/// fmt.debug_list().entries(self.0.iter()).finish()
|
||
/// }
|
||
/// }
|
||
///
|
||
/// // prints "[10, 11]"
|
||
/// println!("{:?}", Foo(vec![10, 11]));
|
||
/// ```
|
||
#[stable(feature = "debug_builders", since = "1.2.0")]
|
||
pub fn debug_list<'b>(&'b mut self) -> DebugList<'b, 'a> {
|
||
builders::debug_list_new(self)
|
||
}
|
||
|
||
/// Creates a `DebugSet` builder designed to assist with creation of
|
||
/// `fmt::Debug` implementations for set-like structures.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```rust
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Foo(Vec<i32>);
|
||
///
|
||
/// impl fmt::Debug for Foo {
|
||
/// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
|
||
/// fmt.debug_set().entries(self.0.iter()).finish()
|
||
/// }
|
||
/// }
|
||
///
|
||
/// // prints "{10, 11}"
|
||
/// println!("{:?}", Foo(vec![10, 11]));
|
||
/// ```
|
||
#[stable(feature = "debug_builders", since = "1.2.0")]
|
||
pub fn debug_set<'b>(&'b mut self) -> DebugSet<'b, 'a> {
|
||
builders::debug_set_new(self)
|
||
}
|
||
|
||
/// Creates a `DebugMap` builder designed to assist with creation of
|
||
/// `fmt::Debug` implementations for map-like structures.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```rust
|
||
/// use std::fmt;
|
||
///
|
||
/// struct Foo(Vec<(String, i32)>);
|
||
///
|
||
/// impl fmt::Debug for Foo {
|
||
/// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
|
||
/// fmt.debug_map().entries(self.0.iter().map(|&(ref k, ref v)| (k, v))).finish()
|
||
/// }
|
||
/// }
|
||
///
|
||
/// // prints "{"A": 10, "B": 11}"
|
||
/// println!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)]));
|
||
/// ```
|
||
#[stable(feature = "debug_builders", since = "1.2.0")]
|
||
pub fn debug_map<'b>(&'b mut self) -> DebugMap<'b, 'a> {
|
||
builders::debug_map_new(self)
|
||
}
|
||
}
|
||
|
||
#[stable(since = "1.2.0", feature = "formatter_write")]
|
||
impl<'a> Write for Formatter<'a> {
|
||
fn write_str(&mut self, s: &str) -> Result {
|
||
self.buf.write_str(s)
|
||
}
|
||
|
||
fn write_char(&mut self, c: char) -> Result {
|
||
self.buf.write_char(c)
|
||
}
|
||
|
||
fn write_fmt(&mut self, args: Arguments) -> Result {
|
||
write(self.buf, args)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Display for Error {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
Display::fmt("an error occurred when formatting an argument", f)
|
||
}
|
||
}
|
||
|
||
// Implementations of the core formatting traits
|
||
|
||
macro_rules! fmt_refs {
|
||
($($tr:ident),*) => {
|
||
$(
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a, T: ?Sized + $tr> $tr for &'a T {
|
||
fn fmt(&self, f: &mut Formatter) -> Result { $tr::fmt(&**self, f) }
|
||
}
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a, T: ?Sized + $tr> $tr for &'a mut T {
|
||
fn fmt(&self, f: &mut Formatter) -> Result { $tr::fmt(&**self, f) }
|
||
}
|
||
)*
|
||
}
|
||
}
|
||
|
||
fmt_refs! { Debug, Display, Octal, Binary, LowerHex, UpperHex, LowerExp, UpperExp }
|
||
|
||
#[stable(feature = "never_type", since = "1.26.0")]
|
||
impl Debug for ! {
|
||
fn fmt(&self, _: &mut Formatter) -> Result {
|
||
*self
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "never_type", since = "1.26.0")]
|
||
impl Display for ! {
|
||
fn fmt(&self, _: &mut Formatter) -> Result {
|
||
*self
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Debug for bool {
|
||
#[inline]
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
Display::fmt(self, f)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Display for bool {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
Display::fmt(if *self { "true" } else { "false" }, f)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Debug for str {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
f.write_char('"')?;
|
||
let mut from = 0;
|
||
for (i, c) in self.char_indices() {
|
||
let esc = c.escape_debug();
|
||
// If char needs escaping, flush backlog so far and write, else skip
|
||
if esc.len() != 1 {
|
||
f.write_str(&self[from..i])?;
|
||
for c in esc {
|
||
f.write_char(c)?;
|
||
}
|
||
from = i + c.len_utf8();
|
||
}
|
||
}
|
||
f.write_str(&self[from..])?;
|
||
f.write_char('"')
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Display for str {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
f.pad(self)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Debug for char {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
f.write_char('\'')?;
|
||
for c in self.escape_debug() {
|
||
f.write_char(c)?
|
||
}
|
||
f.write_char('\'')
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Display for char {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
if f.width.is_none() && f.precision.is_none() {
|
||
f.write_char(*self)
|
||
} else {
|
||
f.pad(self.encode_utf8(&mut [0; 4]))
|
||
}
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<T: ?Sized> Pointer for *const T {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
let old_width = f.width;
|
||
let old_flags = f.flags;
|
||
|
||
// The alternate flag is already treated by LowerHex as being special-
|
||
// it denotes whether to prefix with 0x. We use it to work out whether
|
||
// or not to zero extend, and then unconditionally set it to get the
|
||
// prefix.
|
||
if f.alternate() {
|
||
f.flags |= 1 << (FlagV1::SignAwareZeroPad as u32);
|
||
|
||
if let None = f.width {
|
||
f.width = Some(((mem::size_of::<usize>() * 8) / 4) + 2);
|
||
}
|
||
}
|
||
f.flags |= 1 << (FlagV1::Alternate as u32);
|
||
|
||
let ret = LowerHex::fmt(&(*self as *const () as usize), f);
|
||
|
||
f.width = old_width;
|
||
f.flags = old_flags;
|
||
|
||
ret
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<T: ?Sized> Pointer for *mut T {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
Pointer::fmt(&(*self as *const T), f)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a, T: ?Sized> Pointer for &'a T {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
Pointer::fmt(&(*self as *const T), f)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a, T: ?Sized> Pointer for &'a mut T {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
Pointer::fmt(&(&**self as *const T), f)
|
||
}
|
||
}
|
||
|
||
// Implementation of Display/Debug for various core types
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<T: ?Sized> Debug for *const T {
|
||
fn fmt(&self, f: &mut Formatter) -> Result { Pointer::fmt(self, f) }
|
||
}
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<T: ?Sized> Debug for *mut T {
|
||
fn fmt(&self, f: &mut Formatter) -> Result { Pointer::fmt(self, f) }
|
||
}
|
||
|
||
macro_rules! peel {
|
||
($name:ident, $($other:ident,)*) => (tuple! { $($other,)* })
|
||
}
|
||
|
||
macro_rules! tuple {
|
||
() => ();
|
||
( $($name:ident,)+ ) => (
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<$($name:Debug),*> Debug for ($($name,)*) where last_type!($($name,)+): ?Sized {
|
||
#[allow(non_snake_case, unused_assignments, deprecated)]
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
let mut builder = f.debug_tuple("");
|
||
let ($(ref $name,)*) = *self;
|
||
$(
|
||
builder.field(&$name);
|
||
)*
|
||
|
||
builder.finish()
|
||
}
|
||
}
|
||
peel! { $($name,)* }
|
||
)
|
||
}
|
||
|
||
macro_rules! last_type {
|
||
($a:ident,) => { $a };
|
||
($a:ident, $($rest_a:ident,)+) => { last_type!($($rest_a,)+) };
|
||
}
|
||
|
||
tuple! { T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, }
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<T: Debug> Debug for [T] {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
f.debug_list().entries(self.iter()).finish()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Debug for () {
|
||
#[inline]
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
f.pad("()")
|
||
}
|
||
}
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<T: ?Sized> Debug for PhantomData<T> {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
f.pad("PhantomData")
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<T: Copy + Debug> Debug for Cell<T> {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
f.debug_struct("Cell")
|
||
.field("value", &self.get())
|
||
.finish()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<T: ?Sized + Debug> Debug for RefCell<T> {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
match self.try_borrow() {
|
||
Ok(borrow) => {
|
||
f.debug_struct("RefCell")
|
||
.field("value", &borrow)
|
||
.finish()
|
||
}
|
||
Err(_) => {
|
||
// The RefCell is mutably borrowed so we can't look at its value
|
||
// here. Show a placeholder instead.
|
||
struct BorrowedPlaceholder;
|
||
|
||
impl Debug for BorrowedPlaceholder {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
f.write_str("<borrowed>")
|
||
}
|
||
}
|
||
|
||
f.debug_struct("RefCell")
|
||
.field("value", &BorrowedPlaceholder)
|
||
.finish()
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'b, T: ?Sized + Debug> Debug for Ref<'b, T> {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
Debug::fmt(&**self, f)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'b, T: ?Sized + Debug> Debug for RefMut<'b, T> {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
Debug::fmt(&*(self.deref()), f)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "core_impl_debug", since = "1.9.0")]
|
||
impl<T: ?Sized + Debug> Debug for UnsafeCell<T> {
|
||
fn fmt(&self, f: &mut Formatter) -> Result {
|
||
f.pad("UnsafeCell")
|
||
}
|
||
}
|
||
|
||
// If you expected tests to be here, look instead at the run-pass/ifmt.rs test,
|
||
// it's a lot easier than creating all of the rt::Piece structures here.
|