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#[derive(Debug, Clone)]
pub struct Truncatable {
value: String,
truncator: String,
rtl: bool,
}
impl From<&str> for Truncatable {
fn from(value: &str) -> Self {
Truncatable::new(String::from(value))
}
}
impl From<String> for Truncatable {
fn from(value: String) -> Self {
Truncatable::new(value)
}
}
impl Truncatable {
pub fn new(value: String) -> Self {
Self {
value,
rtl: false,
truncator: String::from("..."),
}
}
pub fn truncator(mut self, truncator: String) -> Self {
self.truncator = truncator;
self
}
pub fn ltr(mut self) -> Self {
self.rtl = false;
self
}
pub fn rtl(mut self) -> Self {
self.rtl = true;
self
}
pub fn truncate(&self, length: usize) -> String {
return format!("{1:.*}", length, self);
}
}
impl std::fmt::Display for Truncatable {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
if let Some(precision) = f.precision() {
if precision < self.value.len() {
if !self.rtl {
f.pad(self.value.as_str())?;
write!(f, "{truncator}", truncator = self.truncator)?;
return Ok(());
} else {
write!(f, "{truncator}", truncator = self.truncator)?;
f.pad(self.value.as_str())?;
return Ok(());
}
}
}
return f.pad(self.value.as_str());
}
}
#[cfg(test)]
mod tests {
use crate::Truncatable;
#[test]
fn build_from_str() {
let trunc = Truncatable::from("Test_Truncatable");
assert_eq!(format!("{}", trunc), String::from("Test_Truncatable"));
}
#[test]
fn default_truncator() {
let trunc = Truncatable::from("Test_Truncatable");
assert_eq!(trunc.truncate(4), String::from("Test..."));
}
#[test]
fn custom_truncator() {
let trunc = Truncatable::from("Test_Truncatable").truncator("-".into());
assert_eq!(trunc.truncate(4), String::from("Test-"));
}
#[test]
fn right_to_left() {
let trunc = Truncatable::from("Test_Truncatable").rtl();
assert_eq!(trunc.truncate(4), "...Test");
let trunc = trunc.ltr();
assert_eq!(trunc.truncate(4), "Test...");
}
#[test]
fn too_long_to_truncate() {
let trunc = Truncatable::from("Test_Truncatable");
assert_eq!(trunc.truncate(20), trunc.value);
assert_eq!(format!("{:.20}", trunc), "Test_Truncatable");
}
#[test]
fn works_with_other_formatting_flags() {
let trunc = Truncatable::from("Test_Truncatable");
let control = String::from("Test_Truncatable");
let f_trunc = format!("{:]<50}", trunc);
let f_control = format!("{:]<50}", control);
assert_eq!(f_trunc, f_control);
}
}