Struct const_format::fmt::DebugList

pub struct DebugList<'f, 'w> { /* private fields */ }

Available on crate feature fmt only.

For debug formatting a list/array.

Example

This example demonstrates how you can debug format a custom type as a list.

#![feature(const_mut_refs)]

use const_format::{Error, Formatter};
use const_format::{formatc, impl_fmt, try_};

use std::ops::Range;

fn main() {
    const LIST: &str = formatc!("{:?}", RangeList(0..5));
     
    assert_eq!(LIST, "[0, 1, 2, 3, 4]");
}

struct RangeList(Range<usize>);

impl_fmt!{
    impl RangeList;
     
    const fn const_debug_fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
        let mut f = f.debug_list();
        let mut i = self.0.start;
        while i < self.0.end {
            try_!(f.entry().write_usize_display(i));
            i+=1;
        }
        f.finish()
    }
}

Implementations

impl<'f, 'w> DebugList<'f, 'w>

pub const fn entry(&mut self) -> &mut Formatter<'w>

Adds a list entry to the formatted output

pub const fn finish(self) -> Result<(), Error>

Finishes writing the list, and if anything went wrong in the entry method,returns an error.