pub trait Debug {
// Required method
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>;
}
Expand description
?
格式。
Debug
应该在面向程序员的调试上下文中格式化输出。
一般来说,您应该只将 derive
和 Debug
实现。
当与备用格式说明符 #?
一起使用时,输出将被漂亮地打印。
有关格式化程序的更多信息,请参见 模块级文档。
如果所有字段都实现 Debug
,则此 trait 可以与 #[derive]
一起使用。当为结构体 derived' 时,它将使用
struct的名称,然后是
{,然后是每个字段名称和
Debug值的逗号分隔列表,然后是
}。 对于
enum,它将使用变体的名称,如果适用,将使用
(,然后是字段的
Debug值,然后是
)`。
Stability
派生的 Debug
格式不稳定,因此 future Rust 版本可能会更改。此外,标准库 (std
、core
、alloc
等) 提供的类型的 Debug
实现并不稳定,并且也可能随着 future Rust 版本而改变。
Examples
派生实现:
#[derive(Debug)]
struct Point {
x: i32,
y: i32,
}
let origin = Point { x: 0, y: 0 };
assert_eq!(format!("The origin is: {origin:?}"), "The origin is: Point { x: 0, y: 0 }");
Run手动实现:
use std::fmt;
struct Point {
x: i32,
y: i32,
}
impl fmt::Debug for Point {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Point")
.field("x", &self.x)
.field("y", &self.y)
.finish()
}
}
let origin = Point { x: 0, y: 0 };
assert_eq!(format!("The origin is: {origin:?}"), "The origin is: Point { x: 0, y: 0 }");
RunFormatter
结构体上有许多辅助方法可以帮助您实现手动实现,例如 debug_struct
。
不希望使用 Formatter
trait 提供的标准调试表示套件 (debug_struct
、debug_tuple
、debug_list
、debug_set
、debug_map
) 的类型可以通过手动向 Formatter
写入任意表示来完成完全自定义的操作。
impl fmt::Debug for Point {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "Point [{} {}]", self.x, self.y)
}
}
Run使用 derive
或 Formatter
上的调试构建器 API 的 Debug
实现支持使用备用标志 {:#?}
的漂亮打印。
使用 #?
进行漂亮的打印:
#[derive(Debug)]
struct Point {
x: i32,
y: i32,
}
let origin = Point { x: 0, y: 0 };
assert_eq!(format!("The origin is: {origin:#?}"),
"The origin is: Point {
x: 0,
y: 0,
}");
RunRequired Methods§
sourcefn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
使用给定的格式化程序格式化该值。
Examples
use std::fmt;
struct Position {
longitude: f32,
latitude: f32,
}
impl fmt::Debug for Position {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_tuple("")
.field(&self.longitude)
.field(&self.latitude)
.finish()
}
}
let position = Position { longitude: 1.987, latitude: 2.983 };
assert_eq!(format!("{position:?}"), "(1.987, 2.983)");
assert_eq!(format!("{position:#?}"), "(
1.987,
2.983,
)");
RunImplementors§
impl Debug for AsciiChar
impl Debug for core::cmp::Ordering
impl Debug for Infallible
impl Debug for Which
impl Debug for c_void
impl Debug for IpAddr
impl Debug for Ipv6MulticastScope
impl Debug for SocketAddr
impl Debug for FpCategory
impl Debug for IntErrorKind
impl Debug for core::sync::atomic::Ordering
impl Debug for TryReserveErrorKind
impl Debug for SearchStep
impl Debug for alloc::fmt::Alignment
impl Debug for bool
impl Debug for char
impl Debug for f32
impl Debug for f64
impl Debug for i8
impl Debug for i16
impl Debug for i32
impl Debug for i64
impl Debug for i128
impl Debug for isize
impl Debug for !
impl Debug for str
impl Debug for u8
impl Debug for u16
impl Debug for u32
impl Debug for u64
impl Debug for u128
impl Debug for ()
impl Debug for usize
impl Debug for TypeId
impl Debug for TryFromSliceError
impl Debug for core::ascii::EscapeDefault
impl Debug for BorrowError
impl Debug for BorrowMutError
impl Debug for CharTryFromError
impl Debug for ParseCharError
impl Debug for DecodeUtf16Error
impl Debug for core::char::EscapeDebug
impl Debug for core::char::EscapeDefault
impl Debug for core::char::EscapeUnicode
impl Debug for ToLowercase
impl Debug for ToUppercase
impl Debug for TryFromCharError
impl Debug for CpuidResult
impl Debug for __m128
impl Debug for __m128bh
impl Debug for __m128d
impl Debug for __m128i
impl Debug for __m256
impl Debug for __m256bh
impl Debug for __m256d
impl Debug for __m256i
impl Debug for __m512
impl Debug for __m512bh
impl Debug for __m512d
impl Debug for __m512i
impl Debug for CStr
impl Debug for FromBytesUntilNulError
impl Debug for FromBytesWithNulError
impl Debug for SipHasher
impl Debug for PhantomPinned
impl Debug for Assume
impl Debug for Ipv4Addr
impl Debug for Ipv6Addr
impl Debug for AddrParseError
impl Debug for SocketAddrV4
impl Debug for SocketAddrV6
impl Debug for ParseFloatError
impl Debug for ParseIntError
impl Debug for TryFromIntError
impl Debug for NonZeroI8
impl Debug for NonZeroI16
impl Debug for NonZeroI32
impl Debug for NonZeroI64
impl Debug for NonZeroI128
impl Debug for NonZeroIsize
impl Debug for NonZeroU8
impl Debug for NonZeroU16
impl Debug for NonZeroU32
impl Debug for NonZeroU64
impl Debug for NonZeroU128
impl Debug for NonZeroUsize
impl Debug for RangeFull
impl Debug for core::ptr::alignment::Alignment
impl Debug for TimSortRun
impl Debug for AtomicBool
impl Debug for AtomicI8
impl Debug for AtomicI16
impl Debug for AtomicI32
impl Debug for AtomicI64
impl Debug for AtomicIsize
impl Debug for AtomicU8
impl Debug for AtomicU16
impl Debug for AtomicU32
impl Debug for AtomicU64
impl Debug for AtomicUsize
impl Debug for Context<'_>
impl Debug for RawWaker
impl Debug for RawWakerVTable
impl Debug for Waker
impl Debug for Duration
impl Debug for TryFromFloatSecsError
impl Debug for AllocError
impl Debug for Global
impl Debug for Layout
impl Debug for LayoutError
impl Debug for TryReserveError
impl Debug for CString
impl Debug for FromVecWithNulError
impl Debug for IntoStringError
impl Debug for NulError
impl Debug for Chars<'_>
impl Debug for EncodeUtf16<'_>
impl Debug for ParseBoolError
impl Debug for Utf8Chunks<'_>
impl Debug for Utf8Error
impl Debug for alloc::string::Drain<'_>
impl Debug for FromUtf8Error
impl Debug for FromUtf16Error
impl Debug for String
impl Debug for Arguments<'_>
impl Debug for Error
impl Debug for dyn Any + 'static
impl Debug for dyn Any + Send + 'static
impl Debug for dyn Any + Send + Sync + 'static
impl<'a> Debug for Demand<'a>
impl<'a> Debug for Source<'a>
impl<'a> Debug for Location<'a>
impl<'a> Debug for PanicInfo<'a>
impl<'a> Debug for EscapeAscii<'a>
impl<'a> Debug for CharSearcher<'a>
impl<'a> Debug for Bytes<'a>
impl<'a> Debug for CharIndices<'a>
impl<'a> Debug for alloc::str::EscapeDebug<'a>
impl<'a> Debug for alloc::str::EscapeDefault<'a>
impl<'a> Debug for alloc::str::EscapeUnicode<'a>
impl<'a> Debug for Lines<'a>
impl<'a> Debug for LinesAny<'a>
impl<'a> Debug for SplitAsciiWhitespace<'a>
impl<'a> Debug for SplitWhitespace<'a>
impl<'a> Debug for Utf8Chunk<'a>
impl<'a, 'b> Debug for CharSliceSearcher<'a, 'b>
impl<'a, 'b> Debug for StrSearcher<'a, 'b>
impl<'a, 'b, const N: usize> Debug for CharArrayRefSearcher<'a, 'b, N>
impl<'a, 'f> Debug for VaList<'a, 'f>where 'f: 'a,
impl<'a, A> Debug for core::option::Iter<'a, A>where A: Debug + 'a,
impl<'a, A> Debug for core::option::IterMut<'a, A>where A: Debug + 'a,
impl<'a, I> Debug for ByRefSized<'a, I>where I: Debug,
impl<'a, I: Debug + Iterator + 'a, A: Debug + Allocator + 'a> Debug for Splice<'a, I, A>where I::Item: Debug,
impl<'a, P> Debug for MatchIndices<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: Debug,
impl<'a, P> Debug for Matches<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: Debug,
impl<'a, P> Debug for RMatchIndices<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: Debug,
impl<'a, P> Debug for RMatches<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: Debug,
impl<'a, P> Debug for alloc::str::RSplit<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: Debug,
impl<'a, P> Debug for alloc::str::RSplitN<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: Debug,
impl<'a, P> Debug for RSplitTerminator<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: Debug,
impl<'a, P> Debug for alloc::str::Split<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: Debug,
impl<'a, P> Debug for alloc::str::SplitInclusive<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: Debug,
impl<'a, P> Debug for alloc::str::SplitN<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: Debug,
impl<'a, P> Debug for SplitTerminator<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: Debug,
impl<'a, T> Debug for core::result::Iter<'a, T>where T: Debug + 'a,
impl<'a, T> Debug for core::result::IterMut<'a, T>where T: Debug + 'a,
impl<'a, T> Debug for Chunks<'a, T>where T: Debug + 'a,
impl<'a, T> Debug for ChunksExact<'a, T>where T: Debug + 'a,
impl<'a, T> Debug for ChunksExactMut<'a, T>where T: Debug + 'a,
impl<'a, T> Debug for ChunksMut<'a, T>where T: Debug + 'a,
impl<'a, T> Debug for RChunks<'a, T>where T: Debug + 'a,
impl<'a, T> Debug for RChunksExact<'a, T>where T: Debug + 'a,
impl<'a, T> Debug for RChunksExactMut<'a, T>where T: Debug + 'a,
impl<'a, T> Debug for RChunksMut<'a, T>where T: Debug + 'a,
impl<'a, T> Debug for Windows<'a, T>where T: Debug + 'a,
impl<'a, T, P> Debug for GroupBy<'a, T, P>where T: 'a + Debug,
impl<'a, T, P> Debug for GroupByMut<'a, T, P>where T: 'a + Debug,
impl<'a, T, const N: usize> Debug for alloc::slice::ArrayChunks<'a, T, N>where T: Debug + 'a,
impl<'a, T, const N: usize> Debug for ArrayChunksMut<'a, T, N>where T: Debug + 'a,
impl<'a, T, const N: usize> Debug for ArrayWindows<'a, T, N>where T: Debug + 'a,
impl<'a, T: Debug + 'a> Debug for alloc::collections::binary_heap::Drain<'a, T>
impl<'a, T: Debug + 'a> Debug for alloc::collections::btree_set::Range<'a, T>
impl<'a, T: Debug + Ord> Debug for DrainSorted<'a, T>
impl<'a, T: Debug, F, A: Debug + Allocator> Debug for alloc::vec::DrainFilter<'a, T, F, A>where F: FnMut(&mut T) -> bool + Debug,
impl<'a, const N: usize> Debug for CharArraySearcher<'a, N>
impl<'f> Debug for VaListImpl<'f>
impl<A> Debug for Repeat<A>where A: Debug,
impl<A> Debug for core::option::IntoIter<A>where A: Debug,
impl<A, B> Debug for Chain<A, B>where A: Debug, B: Debug,
impl<A, B> Debug for Zip<A, B>where A: Debug, B: Debug,
impl<B> Debug for Cow<'_, B>where B: Debug + ToOwned<Owned: Debug> + ?Sized,
impl<B, C> Debug for ControlFlow<B, C>where B: Debug, C: Debug,
impl<Dyn> Debug for DynMetadata<Dyn>where Dyn: ?Sized,
impl<F> Debug for PollFn<F>
impl<F> Debug for FromFn<F>
impl<F> Debug for OnceWith<F>
impl<F> Debug for RepeatWith<F>
impl<F> Debug for CharPredicateSearcher<'_, F>where F: FnMut(char) -> bool,
impl<F> Debug for Fwhere F: FnPtr,
impl<H> Debug for BuildHasherDefault<H>
impl<I> Debug for FromIter<I>where I: Debug,
impl<I> Debug for DecodeUtf16<I>where I: Debug + Iterator<Item = u16>,
impl<I> Debug for Cloned<I>where I: Debug,
impl<I> Debug for Copied<I>where I: Debug,
impl<I> Debug for Cycle<I>where I: Debug,
impl<I> Debug for Enumerate<I>where I: Debug,
impl<I> Debug for Fuse<I>where I: Debug,
impl<I> Debug for Intersperse<I>where I: Debug + Iterator, <I as Iterator>::Item: Clone + Debug,
impl<I> Debug for Peekable<I>where I: Debug + Iterator, <I as Iterator>::Item: Debug,
impl<I> Debug for Skip<I>where I: Debug,
impl<I> Debug for StepBy<I>where I: Debug,
impl<I> Debug for Take<I>where I: Debug,
impl<I, F> Debug for FilterMap<I, F>where I: Debug,
impl<I, F> Debug for Inspect<I, F>where I: Debug,
impl<I, F> Debug for Map<I, F>where I: Debug,
impl<I, G> Debug for IntersperseWith<I, G>where I: Iterator + Debug, <I as Iterator>::Item: Debug, G: Debug,
impl<I, P> Debug for Filter<I, P>where I: Debug,
impl<I, P> Debug for MapWhile<I, P>where I: Debug,
impl<I, P> Debug for SkipWhile<I, P>where I: Debug,
impl<I, P> Debug for TakeWhile<I, P>where I: Debug,
impl<I, St, F> Debug for Scan<I, St, F>where I: Debug, St: Debug,
impl<I, U> Debug for Flatten<I>where I: Debug + Iterator, <I as Iterator>::Item: IntoIterator<IntoIter = U, Item = <U as Iterator>::Item>, U: Debug + Iterator,
impl<I, U, F> Debug for FlatMap<I, U, F>where I: Debug, U: IntoIterator, <U as IntoIterator>::IntoIter: Debug,
impl<I, const N: usize> Debug for core::iter::adapters::array_chunks::ArrayChunks<I, N>where I: Debug + Iterator, <I as Iterator>::Item: Debug,
impl<Idx> Debug for core::ops::range::Range<Idx>where Idx: Debug,
impl<Idx> Debug for RangeFrom<Idx>where Idx: Debug,
impl<Idx> Debug for RangeInclusive<Idx>where Idx: Debug,
impl<Idx> Debug for RangeTo<Idx>where Idx: Debug,
impl<Idx> Debug for RangeToInclusive<Idx>where Idx: Debug,
impl<K, V, F> Debug for alloc::collections::btree_map::DrainFilter<'_, K, V, F>where K: Debug, V: Debug, F: FnMut(&K, &mut V) -> bool,
impl<K, V: Debug> Debug for Values<'_, K, V>
impl<K, V: Debug> Debug for ValuesMut<'_, K, V>
impl<K, V: Debug, A: Allocator + Clone> Debug for IntoValues<K, V, A>
impl<K: Debug + Ord, V, A: Allocator + Clone> Debug for VacantEntry<'_, K, V, A>
impl<K: Debug + Ord, V: Debug, A: Allocator + Clone> Debug for Entry<'_, K, V, A>
impl<K: Debug + Ord, V: Debug, A: Allocator + Clone> Debug for OccupiedEntry<'_, K, V, A>
impl<K: Debug + Ord, V: Debug, A: Allocator + Clone> Debug for OccupiedError<'_, K, V, A>
impl<K: Debug, V> Debug for Keys<'_, K, V>
impl<K: Debug, V, A: Allocator + Clone> Debug for IntoKeys<K, V, A>
impl<K: Debug, V: Debug> Debug for alloc::collections::btree_map::Cursor<'_, K, V>
impl<K: Debug, V: Debug> Debug for alloc::collections::btree_map::Iter<'_, K, V>
impl<K: Debug, V: Debug> Debug for alloc::collections::btree_map::IterMut<'_, K, V>
impl<K: Debug, V: Debug> Debug for alloc::collections::btree_map::Range<'_, K, V>
impl<K: Debug, V: Debug> Debug for RangeMut<'_, K, V>
impl<K: Debug, V: Debug, A> Debug for alloc::collections::btree_map::CursorMut<'_, K, V, A>
impl<K: Debug, V: Debug, A: Allocator + Clone> Debug for BTreeMap<K, V, A>
impl<K: Debug, V: Debug, A: Allocator + Clone> Debug for alloc::collections::btree_map::IntoIter<K, V, A>
impl<P> Debug for Pin<P>where P: Debug,
impl<T> Debug for Bound<T>where T: Debug,
impl<T> Debug for Option<T>where T: Debug,
impl<T> Debug for Poll<T>where T: Debug,
impl<T> Debug for *const Twhere T: ?Sized,
impl<T> Debug for *mut Twhere T: ?Sized,
impl<T> Debug for &Twhere T: Debug + ?Sized,
impl<T> Debug for &mut Twhere T: Debug + ?Sized,
impl<T> Debug for [T]where T: Debug,
impl<T> Debug for (T₁, T₂, …, Tₙ)where T: Debug + ?Sized,
This trait is implemented for tuples up to twelve items long.