Struct std::fmt::DebugTuple
1.2.0 · source · pub struct DebugTuple<'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 tuple as a part of your
Debug::fmt
implementation.
This can be constructed by the Formatter::debug_tuple
method.
§Examples
use std::fmt;
struct Foo(i32, String);
impl fmt::Debug for Foo {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.debug_tuple("Foo")
.field(&self.0)
.field(&self.1)
.finish()
}
}
assert_eq!(
format!("{:?}", Foo(10, "Hello World".to_string())),
"Foo(10, \"Hello World\")",
);
RunImplementations§
source§impl<'a, 'b> DebugTuple<'a, 'b>where
'b: 'a,
impl<'a, 'b> DebugTuple<'a, 'b>where
'b: 'a,
sourcepub fn field(&mut self, value: &dyn Debug) -> &mut DebugTuple<'a, 'b>
pub fn field(&mut self, value: &dyn Debug) -> &mut DebugTuple<'a, 'b>
Adds a new field to the generated tuple struct output.
§Examples
use std::fmt;
struct Foo(i32, String);
impl fmt::Debug for Foo {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.debug_tuple("Foo")
.field(&self.0) // We add the first field.
.field(&self.1) // We add the second field.
.finish() // We're good to go!
}
}
assert_eq!(
format!("{:?}", Foo(10, "Hello World".to_string())),
"Foo(10, \"Hello World\")",
);
Runsourcepub fn field_with<F>(&mut self, value_fmt: F) -> &mut DebugTuple<'a, 'b>
🔬This is a nightly-only experimental API. (debug_closure_helpers
#117729)
pub fn field_with<F>(&mut self, value_fmt: F) -> &mut DebugTuple<'a, 'b>
debug_closure_helpers
#117729)Adds a new field to the generated tuple struct output.
This method is equivalent to DebugTuple::field
, but formats the
value using a provided closure rather than by calling Debug::fmt
.
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 Foo(i32, String);
impl fmt::Debug for Foo {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.debug_tuple("Foo")
.field(&self.0)
.field(&self.1)
.finish() // You need to call it to "finish" the
// tuple formatting.
}
}
assert_eq!(
format!("{:?}", Foo(10, "Hello World".to_string())),
"Foo(10, \"Hello World\")",
);
RunAuto Trait Implementations§
impl<'a, 'b> !RefUnwindSafe for DebugTuple<'a, 'b>
impl<'a, 'b> !Send for DebugTuple<'a, 'b>
impl<'a, 'b> !Sync for DebugTuple<'a, 'b>
impl<'a, 'b> Unpin for DebugTuple<'a, 'b>
impl<'a, 'b> !UnwindSafe for DebugTuple<'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