Struct core::fmt::DebugSet1.2.0[][src]

#[must_use = "must eventually call `finish()` on Debug builders"]
pub struct DebugSet<'a, 'b: 'a> { /* fields omitted */ }
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

Performs the conversion.

Performs the conversion.

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.