cucumber::When!

macro_rules! When {
    ($cuke:expr, $regex:expr, $body:expr) => { ... };
}

Add a When step to a CucumberRegistrar

Example

#[macro_use]
extern crate cucumber;

use cucumber::{
  CucumberRegistrar,
  Cucumber
};

pub fn main () {
  let mut cucumber: Cucumber<u32> = Cucumber::new();

When!(cucumber, "^I spend (\\d+) coins$", |_, world: &mut u32,
(coin_count,): (u32,)| {
    if *world - coin_count < 0 {
      panic!("Tried to spend more coins than were owned")
    } else {
      *world = *world - coin_count;
    }
  });
}