[Cucumber Expressions] for Rust

• Changelog

Rust implementation of [Cucumber Expressions].

This crate provides [AST] parser, and [Regex] expansion of [Cucumber Expressions].

```rust

// Regex expansion requires into-regex feature.

#[cfg(feature = "into-regex")] {

use cucumber_expressions::Expression;

let re = Expression::regex("I have {int} cucumbers in my belly").unwrap(); let caps = re.captures("I have 42 cucumbers in my belly").unwrap();

asserteq!(&caps[0], "I have 42 cucumbers in my belly"); asserteq!(&caps[1], "42");

}

```

Cargo features

• into-regex: Enables expansion into [Regex].

Grammar

This implementation follows a context-free grammar, which isn't yet merged. Original grammar is impossible to follow while creating a performant parser, as it consists errors and describes not an exact [Cucumber Expressions] language, but rather some superset language, while being also context-sensitive. In case you've found some inconsistencies between this implementation and the ones in other languages, please file an issue!

[EBNF] spec of the current context-free grammar implemented by this crate: ```ebnf expression = single-expression*

single-expression = alternation | optional | parameter | text-without-whitespace+ | whitespace+ text-without-whitespace = (- (text-to-escape | whitespace)) | ('\', text-to-escape) text-to-escape = '(' | '{' | '/' | '\'

alternation = single-alternation, (/, single-alternation)+ single-alternation = ((text-in-alternative+, optional*) | (optional+, text-in-alternative+))+ text-in-alternative = (- alternative-to-escape) | ('\', alternative-to-escape) alternative-to-escape = whitespace | '(' | '{' | '/' | '\' whitespace = ' '

optional = '(' text-in-optional+ ')' text-in-optional = (- optional-to-escape) | ('\', optional-to-escape) optional-to-escape = '(' | ')' | '{' | '/' | '\'

parameter = '{', name*, '}' name = (- name-to-escape) | ('\', name-to-escape) name-to-escape = '{' | '}' | '(' | '/' | '\' ```

[Regex] Production Rules

Follows original production rules.

License

This project is licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.