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#[cfg(feature = "future")]
pub use self::future::TapFutureOps;
#[cfg(feature = "future")]
mod future;
#[cfg(test)]
#[cfg_attr(test, macro_use)]
extern crate matches;
pub trait TapResultOps<T, E> {
fn tap_ok<R, F: FnOnce(&mut T) -> R>(self, f: F) -> Self;
fn tap_err<R, F: FnOnce(&mut E) -> R>(self, f: F) -> Self;
}
impl<T, E> TapResultOps<T, E> for Result<T, E> {
fn tap_ok<R, F: FnOnce(&mut T) -> R>(mut self, f: F) -> Self {
if let Ok(mut val) = self.as_mut() {
let _ = f(&mut val);
}
self
}
fn tap_err<R, F: FnOnce(&mut E) -> R>(mut self, f: F) -> Self {
if let Err(mut val) = self.as_mut() {
let _ = f(&mut val);
}
self
}
}
pub trait TapOptionOps<T> {
fn tap_some<R, F: FnOnce(&mut T) -> R>(self, f: F) -> Self;
fn tap_none<R, F: FnOnce() -> R>(self, f: F) -> Self;
}
impl<T> TapOptionOps<T> for Option<T> {
fn tap_some<R, F: FnOnce(&mut T) -> R>(mut self, f: F) -> Self {
if let Some(mut val) = self.as_mut() {
let _ = f(val);
}
self
}
fn tap_none<R, F: FnOnce() -> R>(self, f: F) -> Self {
if self.is_none() {
let _ = f();
}
self
}
}
pub trait TapOps : Sized {
fn tap<R, F: FnOnce(&mut Self) -> R>(mut self, f: F) -> Self {
let _ = f(&mut self);
self
}
}
impl<T> TapOps for T where T: Sized {}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn option() {
let mut foo = 0;
let option = Some(5);
assert_eq!(option.tap_some(|x| foo += *x), Some(5));
assert_eq!(foo, 5);
}
#[test]
fn result() {
let mut foo = 0;
let option: Result<i32, i32> = Ok(5);
assert_eq!(option.tap_ok(|x| foo += *x), Ok(5));
assert_eq!(foo, 5);
}
#[test]
fn tap() {
let mut foo = 0;
assert_eq!(5.tap(|x| foo += *x), 5);
assert_eq!(foo, 5);
}
#[test]
fn mutable() {
let base = [1, 2, 3];
let mutated = base.tap(|mut arr| for elt in arr.iter_mut() {
*elt *= 2;
});
assert_eq!(mutated, [2, 4, 6]);
}
}