8 releases (4 breaking)
0.5.1 | Jan 26, 2023 |
---|---|
0.5.0 | Sep 27, 2022 |
0.4.1 | Aug 4, 2022 |
0.4.0 | May 10, 2022 |
0.1.0 | Nov 12, 2020 |
#13 in #cldr
45,617 downloads per month
Used in 49 crates
(17 directly)
34KB
584 lines
writeable 
writeable
is a utility crate of the ICU4X
project.
It includes [Writeable
], a core trait representing an object that can be written to a
sink implementing std::fmt::Write
. It is an alternative to std::fmt::Display
with the
addition of a function indicating the number of bytes to be written.
Writeable
improves upon std::fmt::Display
in two ways:
- More efficient, since the sink can pre-allocate bytes.
- Smaller code, since the format machinery can be short-circuited.
Examples
use std::fmt;
use writeable::assert_writeable_eq;
use writeable::LengthHint;
use writeable::Writeable;
struct WelcomeMessage<'s> {
pub name: &'s str,
}
impl<'s> Writeable for WelcomeMessage<'s> {
fn write_to<W: fmt::Write + ?Sized>(&self, sink: &mut W) -> fmt::Result {
sink.write_str("Hello, ")?;
sink.write_str(self.name)?;
sink.write_char('!')?;
Ok(())
}
fn writeable_length_hint(&self) -> LengthHint {
// "Hello, " + '!' + length of name
LengthHint::exact(8 + self.name.len())
}
}
let message = WelcomeMessage { name: "Alice" };
assert_writeable_eq!(&message, "Hello, Alice!");
// Types implementing `Writeable` are recommended to also implement `fmt::Display`.
// This can be simply done by redirecting to the `Writeable` implementation:
writeable::impl_display_with_writeable!(WelcomeMessage<'_>);
More Information
For more information on development, authorship, contributing etc. please visit ICU4X home page
.