Struct const_format::fmt::DebugStruct [−][src]
pub struct DebugStruct<'f, 'w> { /* fields omitted */ }
This is supported on crate feature
fmt
only.Expand description
A helper struct for debug formatting a braced struct, or braced variant.
Example
This example demonstrates how you can debug format a struct, and a braced variant.
#![feature(const_mut_refs)]
use const_format::{Error, Formatter};
use const_format::{call_debug_fmt, coerce_to_fmt, formatc, impl_fmt, try_};
fn main() {
const STRUC: &str = formatc!("{:?}", Foo { a: 5, b: [8, 13, 21], c: "34" });
const ENUM_: &str = formatc!("{:?}", Bar::Baz { d: false, e: None });
assert_eq!(STRUC, "Foo { a: 5, b: [8, 13, 21], c: \"34\" }");
assert_eq!(ENUM_, "Baz { d: false, e: None }");
}
struct Foo{
a: u32,
b: [u32; 3],
c: &'static str,
}
enum Bar {
Baz{
d: bool,
e: Option<bool>,
}
}
impl_fmt!{
impl Foo;
const fn const_debug_fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
let mut f = f.debug_struct("Foo");
try_!(coerce_to_fmt!(&self.a).const_debug_fmt(f.field("a")));
try_!(coerce_to_fmt!(&self.b).const_debug_fmt(f.field("b")));
try_!(coerce_to_fmt!(&self.c).const_debug_fmt(f.field("c")));
f.finish()
}
}
impl_fmt!{
impl Bar;
const fn const_debug_fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
match self {
Bar::Baz{d, e} => {
let mut f = f.debug_struct("Baz");
// This macro allows debug formatting some generic types that
// don't have a const_debug_fmt fn, like Options which wrap non-std types.
call_debug_fmt!(std, d, f.field("d"));
call_debug_fmt!(Option, e, f.field("e"));
f.finish()
}
}
}
}