Struct debug2::DebugStruct
source · [−]pub struct DebugStruct<'a, 'b: 'a> { /* private fields */ }
Expand description
A struct to help with 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 debug2::{pprint, Debug, Formatter};
use std::fmt;
struct Foo {
bar: i32,
baz: String,
}
impl Debug for Foo {
fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
fmt.debug_struct("Foo")
.field("bar", &self.bar)
.field("baz", &self.baz)
.finish()
}
}
assert_eq!(
pprint(Foo {
bar: 10,
baz: "Hello World".to_string()
}),
"Foo { bar: 10, baz: \"Hello World\" }",
);
Implementations
sourceimpl<'a, 'b: 'a> DebugStruct<'a, 'b>
impl<'a, 'b: 'a> DebugStruct<'a, 'b>
sourcepub fn field(&mut self, name: &str, value: &dyn Debug) -> &mut Self
pub fn field(&mut self, name: &str, value: &dyn Debug) -> &mut Self
Adds a new field to the generated struct output.
Examples
use debug2::{pprint, Debug, Formatter};
use std::fmt;
struct Bar {
bar: i32,
another: String,
}
impl Debug for Bar {
fn fmt(&self, fmt: &mut 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!(
pprint(Bar {
bar: 10,
another: "Hello World".to_string()
}),
"Bar { bar: 10, another: \"Hello World\", not_existing_field: 1 }",
);
sourcepub fn finish_non_exhaustive(&mut self) -> Result
pub fn finish_non_exhaustive(&mut self) -> Result
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 debug2::{pprint, Debug, Formatter};
use std::fmt;
struct Bar {
bar: i32,
hidden: f32,
}
impl Debug for Bar {
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
fmt.debug_struct("Bar")
.field("bar", &self.bar)
.finish_non_exhaustive() // Show that some other field(s) exist.
}
}
assert_eq!(
pprint(Bar {
bar: 10,
hidden: 1.0
}),
"Bar { bar: 10, .. }",
);
sourcepub fn finish(&mut self) -> Result
pub fn finish(&mut self) -> Result
Finishes output and returns any error encountered.
Examples
use debug2::{pprint, Debug, Formatter};
use std::fmt;
struct Bar {
bar: i32,
baz: String,
}
impl Debug for Bar {
fn fmt(&self, fmt: &mut 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!(
pprint(Bar {
bar: 10,
baz: "Hello World".to_string()
}),
"Bar { bar: 10, baz: \"Hello World\" }",
);
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 · sourcepub fn borrow_mut(&mut self) -> &mut T
pub fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more