pub struct DebugStruct<'a, 'b> where
'b: 'a, { /* private fields */ }
Expand description
A struct to help with fmt::Debug
implementations.
This is useful when you wish to output a formatted struct as a part of your
Debug::fmt
implementation.
This can be constructed by the Formatter::debug_struct
method.
Examples
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()
}
}
assert_eq!(
format!("{:?}", Foo { bar: 10, baz: "Hello World".to_string() }),
"Foo { bar: 10, baz: \"Hello World\" }",
);
Implementations
sourceimpl<'a, 'b> DebugStruct<'a, 'b> where
'b: 'a,
impl<'a, 'b> DebugStruct<'a, 'b> where
'b: 'a,
sourcepub fn field(
&mut self,
name: &str,
value: &dyn Debug
) -> &mut DebugStruct<'a, 'b>
pub fn field(
&mut self,
name: &str,
value: &dyn Debug
) -> &mut DebugStruct<'a, 'b>
Adds a new field to the generated struct output.
Examples
use std::fmt;
struct Bar {
bar: i32,
another: String,
}
impl fmt::Debug for Bar {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.debug_struct("Bar")
.field("bar", &self.bar) // We add `bar` field.
.field("another", &self.another) // We add `another` field.
// We even add a field which doesn't exist (because why not?).
.field("not_existing_field", &1)
.finish() // We're good to go!
}
}
assert_eq!(
format!("{:?}", Bar { bar: 10, another: "Hello World".to_string() }),
"Bar { bar: 10, another: \"Hello World\", not_existing_field: 1 }",
);
1.53.0 · sourcepub fn finish_non_exhaustive(&mut self) -> Result<(), Error>
pub fn finish_non_exhaustive(&mut self) -> Result<(), Error>
Marks the struct as non-exhaustive, indicating to the reader that there are some other fields that are not shown in the debug representation.
Examples
use std::fmt;
struct Bar {
bar: i32,
hidden: f32,
}
impl fmt::Debug for Bar {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.debug_struct("Bar")
.field("bar", &self.bar)
.finish_non_exhaustive() // Show that some other field(s) exist.
}
}
assert_eq!(
format!("{:?}", Bar { bar: 10, hidden: 1.0 }),
"Bar { bar: 10, .. }",
);
sourcepub fn finish(&mut self) -> Result<(), Error>
pub fn finish(&mut self) -> Result<(), Error>
Finishes output and returns any error encountered.
Examples
use std::fmt;
struct Bar {
bar: i32,
baz: String,
}
impl fmt::Debug for Bar {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.debug_struct("Bar")
.field("bar", &self.bar)
.field("baz", &self.baz)
.finish() // You need to call it to "finish" the
// struct formatting.
}
}
assert_eq!(
format!("{:?}", Bar { bar: 10, baz: "Hello World".to_string() }),
"Bar { bar: 10, baz: \"Hello World\" }",
);
Trait Implementations
sourceimpl<'a, 'b> Visit for DebugStruct<'a, 'b>
impl<'a, 'b> Visit for DebugStruct<'a, 'b>
sourcefn record_debug(&mut self, field: &Field, value: &dyn Debug)
fn record_debug(&mut self, field: &Field, value: &dyn Debug)
Visit a value implementing fmt::Debug
.
sourcefn record_f64(&mut self, field: &Field, value: f64)
fn record_f64(&mut self, field: &Field, value: f64)
Visit a double-precision floating point value.
sourcefn record_i64(&mut self, field: &Field, value: i64)
fn record_i64(&mut self, field: &Field, value: i64)
Visit a signed 64-bit integer value.
sourcefn record_u64(&mut self, field: &Field, value: u64)
fn record_u64(&mut self, field: &Field, value: u64)
Visit an unsigned 64-bit integer value.
sourcefn record_bool(&mut self, field: &Field, value: bool)
fn record_bool(&mut self, field: &Field, value: bool)
Visit a boolean value.
sourcefn record_str(&mut self, field: &Field, value: &str)
fn record_str(&mut self, field: &Field, value: &str)
Visit a string value.
sourcefn record_error(&mut self, field: &Field, value: &(dyn Error + 'static))
fn record_error(&mut self, field: &Field, value: &(dyn Error + 'static))
Records a type implementing Error
. Read more
Auto Trait Implementations
impl<'a, 'b> !RefUnwindSafe for DebugStruct<'a, 'b>
impl<'a, 'b> !Send for DebugStruct<'a, 'b>
impl<'a, 'b> !Sync for DebugStruct<'a, 'b>
impl<'a, 'b> Unpin for DebugStruct<'a, 'b> where
'b: 'a,
impl<'a, 'b> !UnwindSafe for DebugStruct<'a, 'b>
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<T> Instrument for T
impl<T> Instrument for T
sourcefn instrument(self, span: Span) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
fn instrument(self, span: Span) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
T: Future, type Output = <T as Future>::Output;
sourcefn in_current_span(self) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
fn in_current_span(self) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
T: Future, type Output = <T as Future>::Output;
impl<V, T> VZip<V> for T where
V: MultiLane<T>,
impl<V, T> VZip<V> for T where
V: MultiLane<T>,
fn vzip(self) -> V
sourceimpl<T> WithSubscriber for T
impl<T> WithSubscriber for T
sourcefn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
where
S: Into<Dispatch>,
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
where
S: Into<Dispatch>,
T: Future, type Output = <T as Future>::Output;
Attaches the provided Subscriber
to this type, returning a
WithDispatch
wrapper. Read more
sourcefn with_current_subscriber(self) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
fn with_current_subscriber(self) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
T: Future, type Output = <T as Future>::Output;
Attaches the current default Subscriber
to this type, returning a
WithDispatch
wrapper. Read more