Crate fluent_comparisons

This crate is for you if you have ever been annoyed at writing repetitive conditions like this

if x < a && y < a && z < a {
// ... do something
}

and wished you could replace that code by something more expressive and less repetitive. Now you can rewrite the code as

use fluent_comparisons::all_of;

if all_of!({x,y,z} < a) {
// ... do something
}

Examples

The crate provides the macros any_of, all_of and none_of to facilitate writing expressive multicomparisons. The arguments don’t need to be numeric, but can be expressions of any type. Furthermore, a syntax for applying transformations to the set on the left hand side is provided.

// the following assertions hold
assert!(none_of!({1,2,3}>4));
assert!(any_of!({1,2,3}.map(|x|x%2)==0));

Brief Description and Key Advantages

In addition to providing an intuitive syntax, the macros compile to the same assembly as the handwritten code (check it on godbolt.org).

A further benefit is lazy evaluation from left to right as seen in the next snippet:

use fluent_comparisons::any_of;

// if cheap_calc(arg1) <=5, then the expensive calculation
// is never performed
let b = any_of!({cheap_calc(arg1), expensive_calc(arg2)}<=5);
// whereas if we did this, the expensive calculation would be
// performed regardless of the result of cheap_calc(arg1)
let b = [cheap_calc(arg1), expensive_calc(arg2)].iter().any(|val|val<=&5);

And finally, you can rest assured in the warm and fuzzy feeling that this crate is excessively tested.

Usage

Refer to the items in the documentation below to learn more about the usage of the macros.

Macros

• all_of
  Compare all values in a set to a common right hand side and decide whether the comparison returns true for all of the values in the set.
• any_of
  Compare all values in a set to a common right hand side and decide whether the comparison returns true for any of the values in the set.
• none_of
  Compare all values in a set to a common right hand side and decide whether the comparison returns true for none of the values in the set.