https://github.com/vonr/set_builder

A procedural macro to create Iterators over a set defined by Haskell-inspired set-builder notation.
https://github.com/vonr/set_builder

Last synced: about 1 month ago
JSON representation

A procedural macro to create Iterators over a set defined by Haskell-inspired set-builder notation.

• Host: GitHub
• URL: https://github.com/vonr/set_builder
• Owner: Vonr
• Created: 2023-09-04T16:12:08.000Z (over 1 year ago)
• Default Branch: master
• Last Pushed: 2023-11-29T03:12:44.000Z (about 1 year ago)
• Last Synced: 2024-11-13T14:56:21.470Z (about 2 months ago)
• Language: Rust
• Size: 21.5 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

README

        
# set_builder

A procedural macro to create Iterators over a set defined by Haskell-inspired [set-builder notation](https://wikipedia.org/wiki/Set-builder_notation).

It should be noted that these "sets" are not true sets in the sense that there is no guarantee that the members (elements) of the set are unique.

# Syntax

## Complex Set

```rust,ignore

//   The pattern of the binding(s)

//               │

//   Mapping     │      ┌── Expression that evaluate into types implementing `IntoIterator`.

//  expression   │      │

//      │        │      │            ┌─ Predicate that evaluates to `bool`

//      ▼        ▼      ▼            ▼

set![ expr : $($(pat <- expr) | $(expr)),* ]

```

## Simple Enumeration Set

This is only provided for mathematical parity and returns arrays rather than Iterators,

array syntax `[...]` should always be preferred to this.

```rust,ignore

//        ┌─ Values to put in the set

//        ▼

set![ $(expr),* ]

```

# Examples

```rust

use set_builder::set;

// Single-binding set with a predicate

let set = set![ x * 2 : x <- [1, 2, 3], *x > 1 ];

assert_eq!(set.collect::>(), [4, 6]);

// Cartesian product without a predicate

let set = set![ (x, y) : x <- [1, 2], y <- [3, 4] ];

assert_eq!(set.collect::>(), [(1, 3), (1, 4), (2, 3), (2, 4)]);

// Simple enumeration

let set = set![ 1, 2, 3, 4, 5 ];

assert_eq!(set, [1, 2, 3, 4, 5]);

```