https://github.com/spenserblack/truthy-rs
Check if a value is "truthy"
https://github.com/spenserblack/truthy-rs
crates rust truthy
Last synced: about 1 month ago
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Check if a value is "truthy"
- Host: GitHub
- URL: https://github.com/spenserblack/truthy-rs
- Owner: spenserblack
- License: apache-2.0
- Created: 2020-08-05T19:33:12.000Z (about 5 years ago)
- Default Branch: master
- Last Pushed: 2020-08-10T18:58:54.000Z (about 5 years ago)
- Last Synced: 2025-08-23T09:25:24.883Z (about 1 month ago)
- Topics: crates, rust, truthy
- Language: Rust
- Homepage:
- Size: 78.1 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE-APACHE
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README
# truthy
[](https://crates.io/crates/truthy)
[](https://docs.rs/truthy)
[](https://travis-ci.com/spenserblack/truthy)
Check if a value is "truthy"
## Behavior
```rust
// non-zero numbers are truthy
0u32.truthy() // false
0f32.truthy() // false
1u32.truthy() // true
1f32.truthy() // true
// empty strings are not truthy
"".truthy() // false
" ".truthy() // true
// Options are truthy if not None and their value is truthy
let none: Option<()> = None;
let falsy_inner = Some(false);
let truthy_inner = Some(true);
none.truthy() // false
falsy_inner.truthy() // false
truthy_inner.truthy() // true
// Results are truthy if Ok and value is truthy
let falsy_err: Result<(), _> = Err(false);
let truthy_err: Result<(), _> = Err(true);
let falsy_ok: Result<_, ()> = Ok(false);
let truthy_ok: Result<_, ()> = Ok(true);
falsy_err.truthy() // false
truthy_err.truthy() // false
falsy_ok.truthy() // false
truthy_ok.truthy() // true
// Empty vecs and arrays are falsy
let empty_array: [();0] = [];
let empty_vec: Vec<()> = Vec::new();
empty_array.truthy() // false
empty_vec.truthy() // false
// The truthy behavior of arrays and vecs also applies to tuples from size 0 to 12
let empty_tuple = ();
let not_empty_tuple = (1, "2", '3');
empty_tuple.truthy() // false
not_empty_tuple.truthy() // true
```
## `truthy!` macro
```rust
let my_bool = x.truthy() && y.truthy() || !z.truthy();
```
The above code can be a bit annoying, having to repeat `.truthy()` multiple times. The `truthy!`
macro appends `.truthy()` to save you time.
```rust
let my_bool = truthy!(x && y || !z);
```
You can run the [example][truthy! example] with `cargo run --example truthy_macro`.
### Limitations
The `truthy!` macro cannot take non-boolean expressions. The only valid tokens in `truthy!` are
`(`, `)`, `!`, `&&`, `||`, and identities. For example, the following would fail to compile.
```rust
truthy!(Some(1).unwrap() && 0 + 1);
```
To get around this, you would need to assign the expressions before using `truthy!`.
```rust
let x = Some(1).unwrap();
let y = 0 + 1;
truthy!(x && y);
```
## Features
### `and-or`
This crate has an `and-or` feature, which will provide the functions `truthy_and` and `truthy_or` to
any type that implements `Truthy` and `Sized`.
For example, `true.truthy_and("It was truthy!")` returns `Some("It was truthy!")`.
You can run the [example][and-or example] with `cargo run --features and-or --example and_or`.
[truthy! example]: https://github.com/spenserblack/truthy-rs/blob/master/examples/truthy_macro.rs
[and-or example]: https://github.com/spenserblack/truthy-rs/blob/master/examples/and_or.rs