Trait collections::fmt::Debug
[−]
[src]
pub trait Debug {
fn fmt(&self, &mut Formatter) -> Result<(), Error>;
}Format trait for the ? character.
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.
This trait can be used with #[derive].
Examples
Deriving an implementation:
fn main() { #[derive(Debug)] struct Point { x: i32, y: i32, } let origin = Point { x: 0, y: 0 }; println!("The origin is: {:?}", origin); }#[derive(Debug)] struct Point { x: i32, y: i32, } let origin = Point { x: 0, y: 0 }; println!("The origin is: {:?}", origin);
Manually implementing:
fn main() { 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); }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:
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 implementations using either derive or the debug builder API
on Formatter support pretty printing using the alternate flag: {:#?}.
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:
The origin is: Point {
x: 0,
y: 0
}
Required Methods
Implementors
impl<T> Debug for Box<T> where T: Debug + ?Sizedimpl<T: Debug + Ord> Debug for BinaryHeap<T>impl<K: Debug, V: Debug> Debug for BTreeMap<K, V>impl<T: Debug> Debug for BTreeSet<T>impl<'a, B: ?Sized> Debug for Cow<'a, B> where B: Debug + ToOwned, B::Owned: Debugimpl<E: CLike + Debug> Debug for EnumSet<E>impl Debug for ()impl<T> Debug for [T] where T: Debugimpl<T11> Debug for (T11,) where T11: Debugimpl<T10, T11> Debug for (T10, T11) where T11: Debug, T10: Debugimpl<T9, T10, T11> Debug for (T9, T10, T11) where T11: Debug, T9: Debug, T10: Debugimpl<T8, T9, T10, T11> Debug for (T8, T9, T10, T11) where T8: Debug, T9: Debug, T11: Debug, T10: Debugimpl<T7, T8, T9, T10, T11> Debug for (T7, T8, T9, T10, T11) where T9: Debug, T10: Debug, T8: Debug, T7: Debug, T11: Debugimpl<T6, T7, T8, T9, T10, T11> Debug for (T6, T7, T8, T9, T10, T11) where T7: Debug, T8: Debug, T9: Debug, T6: Debug, T11: Debug, T10: Debugimpl<T5, T6, T7, T8, T9, T10, T11> Debug for (T5, T6, T7, T8, T9, T10, T11) where T10: Debug, T9: Debug, T7: Debug, T8: Debug, T6: Debug, T5: Debug, T11: Debugimpl<T4, T5, T6, T7, T8, T9, T10, T11> Debug for (T4, T5, T6, T7, T8, T9, T10, T11) where T10: Debug, T5: Debug, T8: Debug, T4: Debug, T7: Debug, T9: Debug, T11: Debug, T6: Debugimpl<T3, T4, T5, T6, T7, T8, T9, T10, T11> Debug for (T3, T4, T5, T6, T7, T8, T9, T10, T11) where T11: Debug, T6: Debug, T8: Debug, T3: Debug, T5: Debug, T9: Debug, T10: Debug, T7: Debug, T4: Debugimpl<T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> Debug for (T2, T3, T4, T5, T6, T7, T8, T9, T10, T11) where T8: Debug, T11: Debug, T9: Debug, T3: Debug, T10: Debug, T5: Debug, T4: Debug, T7: Debug, T6: Debug, T2: Debugimpl<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> Debug for (T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11) where T11: Debug, T7: Debug, T2: Debug, T9: Debug, T8: Debug, T1: Debug, T3: Debug, T5: Debug, T10: Debug, T4: Debug, T6: Debugimpl<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> Debug for (T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11) where T5: Debug, T10: Debug, T11: Debug, T0: Debug, T8: Debug, T1: Debug, T7: Debug, T6: Debug, T2: Debug, T3: Debug, T9: Debug, T4: Debugimpl<T> Debug for *mut Timpl<T> Debug for *const Timpl Debug for f64impl Debug for f32impl Debug for charimpl Debug for strimpl Debug for boolimpl Debug for u64impl Debug for i64impl Debug for u32impl Debug for i32impl Debug for u16impl Debug for i16impl Debug for u8impl Debug for i8impl Debug for usizeimpl Debug for isizeimpl<T> Debug for [T; 32] where T: Debugimpl<T> Debug for [T; 31] where T: Debugimpl<T> Debug for [T; 30] where T: Debugimpl<T> Debug for [T; 29] where T: Debugimpl<T> Debug for [T; 28] where T: Debugimpl<T> Debug for [T; 27] where T: Debugimpl<T> Debug for [T; 26] where T: Debugimpl<T> Debug for [T; 25] where T: Debugimpl<T> Debug for [T; 24] where T: Debugimpl<T> Debug for [T; 23] where T: Debugimpl<T> Debug for [T; 22] where T: Debugimpl<T> Debug for [T; 21] where T: Debugimpl<T> Debug for [T; 20] where T: Debugimpl<T> Debug for [T; 19] where T: Debugimpl<T> Debug for [T; 18] where T: Debugimpl<T> Debug for [T; 17] where T: Debugimpl<T> Debug for [T; 16] where T: Debugimpl<T> Debug for [T; 15] where T: Debugimpl<T> Debug for [T; 14] where T: Debugimpl<T> Debug for [T; 13] where T: Debugimpl<T> Debug for [T; 12] where T: Debugimpl<T> Debug for [T; 11] where T: Debugimpl<T> Debug for [T; 10] where T: Debugimpl<T> Debug for [T; 9] where T: Debugimpl<T> Debug for [T; 8] where T: Debugimpl<T> Debug for [T; 7] where T: Debugimpl<T> Debug for [T; 6] where T: Debugimpl<T> Debug for [T; 5] where T: Debugimpl<T> Debug for [T; 4] where T: Debugimpl<T> Debug for [T; 3] where T: Debugimpl<T> Debug for [T; 2] where T: Debugimpl<T> Debug for [T; 1] where T: Debugimpl<T> Debug for [T; 0] where T: Debugimpl Debug for Errorimpl<'a> Debug for Arguments<'a>impl<A: Debug> Debug for LinkedList<A>impl<'a, T> Debug for Chunks<'a, T> where T: 'a + Debugimpl<'a, T> Debug for Windows<'a, T> where T: 'a + Debugimpl<'a, T> Debug for Iter<'a, T> where T: 'a + Debugimpl<'a, T> Debug for IterMut<'a, T> where T: 'a + Debugimpl<'a, T, P> Debug for SplitMut<'a, T, P> where T: 'a + Debug, P: FnMut(&T) -> boolimpl<'a, T> Debug for ChunksMut<'a, T> where T: 'a + Debugimpl<'a, T, P> Debug for Split<'a, T, P> where T: 'a + Debug, P: FnMut(&T) -> boolimpl<'a, T, P> Debug for SplitN<'a, T, P> where T: 'a + Debug, P: FnMut(&T) -> boolimpl<'a, T, P> Debug for RSplitN<'a, T, P> where P: FnMut(&T) -> bool, T: 'a + Debugimpl<'a, T, P> Debug for SplitNMut<'a, T, P> where P: FnMut(&T) -> bool, T: 'a + Debugimpl<'a, T, P> Debug for RSplitNMut<'a, T, P> where P: FnMut(&T) -> bool, T: 'a + Debugimpl Debug for Utf8Errorimpl<'a> Debug for Lines<'a>impl<'a> Debug for LinesAny<'a>impl Debug for CharRangeimpl<'a, P> Debug for Split<'a, P> where P: Pattern<'a>, P::Searcher: Debugimpl<'a, P> Debug for RSplit<'a, P> where P: Pattern<'a>, P::Searcher: Debugimpl<'a, P> Debug for SplitN<'a, P> where P: Pattern<'a>, P::Searcher: Debugimpl<'a, P> Debug for RSplitN<'a, P> where P: Pattern<'a>, P::Searcher: Debugimpl<'a, P> Debug for SplitTerminator<'a, P> where P: Pattern<'a>, P::Searcher: Debugimpl<'a, P> Debug for RSplitTerminator<'a, P> where P: Pattern<'a>, P::Searcher: Debugimpl<'a, P> Debug for Matches<'a, P> where P: Pattern<'a>, P::Searcher: Debugimpl<'a, P> Debug for RMatches<'a, P> where P: Pattern<'a>, P::Searcher: Debugimpl<'a, P> Debug for MatchIndices<'a, P> where P: Pattern<'a>, P::Searcher: Debugimpl<'a, P> Debug for RMatchIndices<'a, P> where P: Pattern<'a>, P::Searcher: Debugimpl<'a> Debug for Chars<'a>impl<'a> Debug for CharIndices<'a>impl<'a> Debug for Bytes<'a>impl Debug for ParseBoolErrorimpl Debug for SearchStepimpl<'a> Debug for CharSearcher<'a>impl<'a, 'b> Debug for CharSliceSearcher<'a, 'b>impl<'a, F> Debug for CharPredicateSearcher<'a, F> where F: FnMut(char) -> boolimpl<'a, 'b> Debug for StrSearcher<'a, 'b>impl Debug for FromUtf8Errorimpl Debug for FromUtf16Errorimpl Debug for Stringimpl Debug for ParseErrorimpl<T: Debug> Debug for Vec<T>impl<T: Debug> Debug for VecDeque<T>impl Debug for RangeFullimpl<Idx> Debug for Range<Idx> where Idx: Debugimpl<Idx> Debug for RangeFrom<Idx> where Idx: Debugimpl<Idx> Debug for RangeTo<Idx> where Idx: Debugimpl<Idx> Debug for RangeInclusive<Idx> where Idx: Debugimpl<Idx> Debug for RangeToInclusive<Idx> where Idx: Debugimpl<T: Debug> Debug for Bound<T>