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// This file is part of ICU4X. For terms of use, please see the file
// called LICENSE at the top level of the ICU4X source tree
// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
// This example illustrates a very simple type implementing Writeable.
#![no_main] // https://github.com/unicode-org/icu4x/issues/395
icu_benchmark_macros::instrument!();
use std::fmt;
use writeable::*;
struct WriteableMessage<W: Writeable>(W);
const GREETING: Part = Part {
category: "meaning",
value: "greeting",
};
const EMOJI: Part = Part {
category: "meaning",
value: "emoji",
};
impl<V: Writeable> Writeable for WriteableMessage<V> {
fn write_to_parts<W: PartsWrite + ?Sized>(&self, sink: &mut W) -> fmt::Result {
use fmt::Write;
sink.with_part(GREETING, |g| {
g.write_str("Hello")?;
g.write_str(" ")?;
self.0.write_to(g)
})?;
sink.write_char(' ')?;
sink.with_part(EMOJI, |e| e.write_char('😅'))
}
fn writeable_length_hint(&self) -> LengthHint {
LengthHint::exact(11) + self.0.writeable_length_hint()
}
}
impl<V: Writeable> fmt::Display for WriteableMessage<V> {
#[inline]
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.write_to(f)
}
}
fn main() {
let (string, parts) =
writeable::_internal::writeable_to_parts_for_test(&WriteableMessage("world"));
assert_eq!(string, "Hello world 😅");
// Print the greeting only
let (start, end, _) = parts
.into_iter()
.find(|(_, _, part)| part == &GREETING)
.unwrap();
println!("{}", &string[start..end]);
}
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