pub struct DebugList<'a, 'b: 'a> { /* private fields */ }
Expand description
A struct to help with fmt::Debug
implementations.
This is useful when you wish to output a formatted list of items as a part
of your Debug::fmt
implementation.
This can be constructed by the Formatter::debug_list
method.
§Examples
Implementations§
source§impl<'a, 'b: 'a> DebugList<'a, 'b>
impl<'a, 'b: 'a> DebugList<'a, 'b>
1.2.0 · sourcepub fn entry(&mut self, entry: &dyn Debug) -> &mut Self
pub fn entry(&mut self, entry: &dyn Debug) -> &mut Self
Adds a new entry to the list output.
§Examples
use std::fmt;
struct Foo(Vec<i32>, Vec<u32>);
impl fmt::Debug for Foo {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.debug_list()
.entry(&self.0) // We add the first "entry".
.entry(&self.1) // We add the second "entry".
.finish()
}
}
assert_eq!(
format!("{:?}", Foo(vec![10, 11], vec![12, 13])),
"[[10, 11], [12, 13]]",
);
sourcepub fn entry_with<F>(&mut self, entry_fmt: F) -> &mut Self
🔬This is a nightly-only experimental API. (debug_closure_helpers
#117729)
pub fn entry_with<F>(&mut self, entry_fmt: F) -> &mut Self
debug_closure_helpers
#117729)Adds a new entry to the list output.
This method is equivalent to DebugList::entry
, but formats the
entry using a provided closure rather than by calling Debug::fmt
.
1.2.0 · sourcepub fn entries<D, I>(&mut self, entries: I) -> &mut Selfwhere
D: Debug,
I: IntoIterator<Item = D>,
pub fn entries<D, I>(&mut self, entries: I) -> &mut Selfwhere
D: Debug,
I: IntoIterator<Item = D>,
Adds the contents of an iterator of entries to the list output.
§Examples
1.84.0 · sourcepub fn finish_non_exhaustive(&mut self) -> Result
pub fn finish_non_exhaustive(&mut self) -> Result
Marks the list as non-exhaustive, indicating to the reader that there are some other elements that are not shown in the debug representation.
§Examples
use std::fmt;
struct Foo(Vec<i32>);
impl fmt::Debug for Foo {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
// Print at most two elements, abbreviate the rest
let mut f = fmt.debug_list();
let mut f = f.entries(self.0.iter().take(2));
if self.0.len() > 2 {
f.finish_non_exhaustive()
} else {
f.finish()
}
}
}
assert_eq!(
format!("{:?}", Foo(vec![1, 2, 3, 4])),
"[1, 2, ..]",
);
Auto Trait Implementations§
impl<'a, 'b> Freeze for DebugList<'a, 'b>
impl<'a, 'b> !RefUnwindSafe for DebugList<'a, 'b>
impl<'a, 'b> !Send for DebugList<'a, 'b>
impl<'a, 'b> !Sync for DebugList<'a, 'b>
impl<'a, 'b> Unpin for DebugList<'a, 'b>
impl<'a, 'b> !UnwindSafe for DebugList<'a, 'b>
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more