Struct core::fmt::DebugSet

1.2.0 · source ·
pub struct DebugSet<'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 set of items as a part of your Debug::fmt implementation.

This can be constructed by the Formatter::debug_set method.

Examples

use std::fmt;

struct Foo(Vec<i32>);

impl fmt::Debug for Foo {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        fmt.debug_set().entries(self.0.iter()).finish()
    }
}

assert_eq!(
    format!("{:?}", Foo(vec![10, 11])),
    "{10, 11}",
);
Run

Implementations§

Adds a new entry to the set 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_set()
           .entry(&self.0) // Adds the first "entry".
           .entry(&self.1) // Adds the second "entry".
           .finish()
    }
}

assert_eq!(
    format!("{:?}", Foo(vec![10, 11], vec![12, 13])),
    "{[10, 11], [12, 13]}",
);
Run

Adds the contents of an iterator of entries to the set 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_set()
           .entries(self.0.iter()) // Adds the first "entry".
           .entries(self.1.iter()) // Adds the second "entry".
           .finish()
    }
}

assert_eq!(
    format!("{:?}", Foo(vec![10, 11], vec![12, 13])),
    "{10, 11, 12, 13}",
);
Run

Finishes output and returns any error encountered.

Examples
use std::fmt;

struct Foo(Vec<i32>);

impl fmt::Debug for Foo {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.debug_set()
           .entries(self.0.iter())
           .finish() // Ends the struct formatting.
    }
}

assert_eq!(
    format!("{:?}", Foo(vec![10, 11])),
    "{10, 11}",
);
Run

Auto Trait Implementations§

Blanket Implementations§

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.