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2 releases
0.1.2 | Mar 17, 2021 |
---|---|
0.1.0 | Mar 17, 2021 |
#25 in #chaining
28KB
287 lines
ea trait library
This trait provide helper function and macro called chain
to ease chaining of function where output of first function piped directly as input to another function and so forth.
Use case 1 - Macro chain
use ea::chain;
fn simple_add(a : i32, b : i32, c : i32) -> i32 {
a + b + c
}
fn pass_through(v : f64) -> f64 {
v
}
assert_eq!(
6f64,
chain!(
simple_add(1, 2, 3),
|result: i32| {(result as f64).powi(2)},
|sqr: f64| {sqr.powf(0.5)},
pass_through,
pass_through
)
);
Use case 2 - function chain
use ea::chain;
fn simple_add(a : i32, b : i32, c : i32) -> i32 {
a + b + c
}
fn pass_through(v : f64) -> f64 {
v
}
assert_eq!(6f64, *chain(simple_add(1, 2, 3))
.chain(|result| {(result as f64).powi(2)})
.chain(|sqr| sqr.powf(0.5))
.chain(pass_through)
.chain(pass_through));
lib.rs
:
Utilities macro/function to ease function chain to be less verbose.
This crate provide two usage style, a macro chain
and a function chain
.
Sample showcase
Case 1 chain by using a helper macro
use ea::chain;
fn simple_add(a : i32, b : i32, c : i32) -> i32 {
a + b + c
}
fn pass_through(v : f64) -> f64 {
v
}
assert_eq!(
6f64,
chain!(
simple_add(1, 2, 3),
|result: i32| {(result as f64).powi(2)},
|sqr: f64| {sqr.powf(0.5)},
pass_through,
pass_through
)
);
// This macro will expand to:
assert_eq!(
6f64,
pass_through(
pass_through(
(|sqr: f64| {sqr.powf(0.5)})(
(|result: i32| {(result as f64).powi(2)})(
simple_add(1, 2, 3)
)
)
)
)
);
Case 2 chain by using helper function
use ea::chain;
fn simple_add(a : i32, b : i32, c : i32) -> i32 {
a + b + c
}
fn pass_through(v : f64) -> f64 {
v
}
assert_eq!(6f64, *chain(simple_add(1, 2, 3))
.chain(|result| {(result as f64).powi(2)})
.chain(|sqr| sqr.powf(0.5))
.chain(pass_through)
.chain(pass_through));